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rfc:rfc2297

Network Working Group P. Newman, Nokia Request for Comments: 2297 W. Edwards, Sprint Updates: 1987 R. Hinden, Nokia Category: Informational E. Hoffman, Nokia

                                                          F. Ching Liaw
                                                         T. Lyon, Nokia
                                                 G. Minshall, Fiberlane
                                                             March 1998
     Ipsilon's General Switch Management Protocol Specification
                            Version 2.0

Status of this Memo

 This memo provides information for the Internet community.  It does
 not specify an Internet standard of any kind.  Distribution of this
 memo is unlimited.

Copyright Notice

 Copyright (C) The Internet Society (1998).  All Rights Reserved.

Abstract

 This memo specifies enhancements to the  General Switch Management
 Protocol (GSMP) [RFC1987]. The major enhancement is the addition of
 Quality of Service (QoS) messages. Other improvements have been made
 to the protocol resulting from operational experience. GSMP is a
 general purpose protocol to control an ATM switch. It allows a
 controller to establish and release connections across the switch;
 add and delete leaves on a multicast connection; manage switch ports;
 request configuration information; and request statistics.

Newman, et. al. Informational [Page 1] RFC 2297 Ipsilon's General Switch Management March 1998

Table of Contents

 1. Introduction....................................................3
 2. GSMP Packet Encapsulation.......................................4
    2.1 ATM Encapsulation...........................................4
    2.2 Ethernet Encapsulation......................................6
 3. Common Definitions and Procedures...............................7
    3.1 GSMP Packet Format..........................................8
    3.2 Failure Response Messages..................................11
 4. Connection Management Messages.................................16
    4.1 Add Branch Message.........................................21
    4.2 Delete Tree Message........................................23
    4.3 Verify Tree Message........................................24
    4.4 Delete All Message.........................................24
    4.5 Delete Branches Message....................................25
    4.6 Move Branch Message........................................27
 5. Port Management Messages.......................................29
    5.1 Port Management Message....................................29
    5.2 Label Range Message........................................34
 6. State and Statistics Messages..................................37
    6.1 Connection Activity Message................................38
    6.2 Statistics Messages........................................40
        6.2.1 Port Statistics Message..............................44
        6.2.2 Connection Statistics Message........................44
        6.2.3 QoS Class Statistics Message.........................44
    6.3 Report Connection State Message............................45
 7. Configuration Messages.........................................49
    7.1 Switch Configuration Message...............................50
    7.2 Port Configuration Message.................................51
    7.3 All Ports Configuration Message............................57
 8. Event Messages.................................................59
    8.1 Port Up Message............................................60
    8.2 Port Down Message..........................................60
    8.3 Invalid VPI/VCI Message....................................61
    8.4 New Port Message...........................................61
    8.5 Dead Port Message..........................................61
 9. Quality of Service Messages....................................61
    9.1 Abstract Switch Model......................................62
    9.2 QoS Configuration Message..................................66
    9.3 Scheduler Establishment Message............................74

Newman, et. al. Informational [Page 2] RFC 2297 Ipsilon's General Switch Management March 1998

    9.4 QoS Class Establishment Message............................78
    9.5 QoS Release Message........................................85
    9.6 QoS Connection Management Message..........................86
    9.7 QoS Failure Response Codes.................................97
 10. Adjacency Protocol............................................97
    10.1 Packet Format.............................................98
    10.2 Procedure.................................................101
    10.3 Loss of Synchronization...................................103
 11. Summary of Failure Response Codes.............................104
 12. Summary of Message Set........................................105
 References........................................................107
 Security Considerations...........................................107
 Authors' Addresses................................................107
 Full Copyright Statement..........................................109

1. Introduction

 The General Switch Management Protocol (GSMP), is a general purpose
 protocol to control an ATM switch. GSMP allows a controller to
 establish and release connections across the switch; add and delete
 leaves on a multicast connection; manage switch ports; request
 configuration information; and request statistics. It also allows the
 switch to inform the controller of asynchronous events such as a link
 going down. GSMP runs across an ATM link connecting the controller to
 the switch, on a control connection (virtual channel) established at
 initialization. GSMP operation across an Ethernet link is also
 specified. The GSMP protocol is asymmetric, the controller being the
 master and the switch being the slave. Multiple switches may be
 controlled by a single controller using multiple instantiations of
 the protocol over separate control connections.
 A switch is assumed to contain multiple "ports". Each port is a
 combination of one "input port" and one "output port". Some GSMP
 requests refer to the port as a whole whereas other requests are
 specific to the input port or the output port.  ATM cells arrive at
 the switch from an external communication link on incoming virtual
 paths or virtual channels at an input port. ATM cells depart from the
 switch to an external communication link on outgoing virtual paths or
 virtual channels from an output port. Virtual paths on a port or link
 are referenced by their virtual path identifier (VPI). Virtual
 channels on a port or link are referenced by their virtual path and
 virtual channel identifiers (VPI/VCI).

Newman, et. al. Informational [Page 3] RFC 2297 Ipsilon's General Switch Management March 1998

 A virtual channel connection across a switch is formed by connecting
 an incoming virtual channel to one or more outgoing virtual channels.
 Virtual channel connections are referenced by the input port on which
 they arrive and the virtual path and virtual channel identifiers
 (VPI/VCI) of their incoming virtual channel. A virtual path
 connection across a switch is formed by connecting an incoming
 virtual path to one or more outgoing virtual paths. Virtual path
 connections are referenced by the input port on which they arrive and
 their virtual path identifier (VPI).  In a virtual path connection
 the value of the VCI in each cell on that, connection is not used by
 the switch and remains unchanged by the switch.
 GSMP supports point-to-point and point-to-multipoint connections. A
 multipoint-to-point connection is specified by establishing multiple
 point-to-point connections each of them specifying the same output
 branch. A multipoint-to-multipoint connection is specified by
 establishing multiple point-to-multipoint trees each of them
 specifying the same output branches.
 In general a virtual channel is established with a certain quality of
 service (QoS). A rich set of QoS messages is introduced in this
 version of the protocol. However, implementation or operation of GSMP
 without any of the messages defined in Section 9, "Quality of service
 messages," is permitted.  In this case each virtual channel
 connection or virtual path connection may be assigned a priority when
 it is established. It may be assumed that for virtual connections
 that share the same output port, an ATM cell on a connection with a
 higher priority is much more likely to exit the switch before an ATM
 cell on a connection with a lower priority if they are both in the
 switch at the same time. The number of priorities that each port of
 the switch supports may be obtained from the port configuration
 message.
 GSMP contains an adjacency protocol. The adjacency protocol is used
 to synchronize state across the link, to negotiate which version of
 the GSMP protocol to use, to discover the identity of the entity at
 the other end of a link, and to detect when it changes.

2. GSMP Packet Encapsulation

2.1 ATM Encapsulation

 GSMP packets are variable length and for an ATM data link layer they
 are encapsulated directly in an AAL-5 CPCS-PDU [I.363] with an
 LLC/SNAP header as illustrated:

Newman, et. al. Informational [Page 4] RFC 2297 Ipsilon's General Switch Management March 1998

  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |               LLC (0xAA-AA-03)                |               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+               +
 |                   SNAP (0x00-00-00-88-0C)                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 ~                         GSMP Message                          ~
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                     Pad (0 - 47 octets)                       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 +               AAL-5 CPCS-PDU Trailer (8 octets)               +
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 (The convention in the documentation of Internet Protocols [RFC1700]
 is to express numbers in decimal. Numbers in hexadecimal format are
 specified by prefacing them with the characters "0x".  Data is
 pictured in "big-endian" order. That is, fields are described left to
 right, with the most significant octet on the left and the least
 significant octet on the right. Whenever a diagram shows a group of
 octets, the order of transmission of those octets is the normal order
 in which they are read in English. Whenever an octet represents a
 numeric quantity the left most bit in the diagram is the high order
 or most significant bit. That is, the bit labeled 0 is the most
 significant bit. Similarly, whenever a multi-octet field represents a
 numeric quantity the left most bit of the whole field is the most
 significant bit. When a multi-octet quantity is transmitted, the most
 significant octet is transmitted first. This is the same coding
 convention as is used in the ATM layer [I.361] and AAL-5 [I.363].)
 The LLC/SNAP header contains the octets: 0xAA 0xAA 0x03 0x00 0x00
 0x00 0x88 0x0C. (0x880C is the assigned Ethertype for GSMP.)
 The maximum transmission unit (MTU) of the GSMP Message field is 1492
 octets.
 The virtual channel over which a GSMP session is established between
 a controller and the switch it is controlling is called the GSMP
 control channel.  The default VPI and VCI of the GSMP control channel
 for LLC/SNAP encapsulated GSMP messages on an ATM data link layer is:
    VPI = 0
    VCI = 15.

Newman, et. al. Informational [Page 5] RFC 2297 Ipsilon's General Switch Management March 1998

2.2 Ethernet Encapsulation

 GSMP packets may be encapsulated on an Ethernet data link as
 illustrated:
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      Destination Address                      |
 |                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                               |                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
 |                         Source Address                        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Ethertype (0x88-0C)       |                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
 |                                                               |
 ~                         GSMP Message                          ~
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                        Sender Instance                        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                       Receiver Instance                       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                              Pad                              |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                       Frame Check Sequence                    |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Destination Address
           For the SYN message of the adjacency protocol the
           Destination Address is the broadcast address
           0xFFFFFFFFFFFF. (Alternatively, it is also valid to
           configure the node with the unicast 48-bit IEEE MAC address
           of the destination. In this case the configured unicast
           Destination Address is used in the SYN message.) For all
           other messages the Destination Address is the unicast 48-
           bit IEEE MAC address of the destination. This address may
           be discovered from the Source Address field of messages
           received during synchronization of the adjacency protocol.
 Source Address
           For all messages the Source Address is the 48-bit IEEE MAC
           address of the sender.
 Ethertype
           The assigned Ethertype for GSMP is 0x880C.

Newman, et. al. Informational [Page 6] RFC 2297 Ipsilon's General Switch Management March 1998

 GSMP Message
           The maximum transmission unit (MTU) of the GSMP Message
           field is 1492 octets.
 Sender Instance
           The Sender Instance number for the link obtained from the
           adjacency protocol.  This field is already present in the
           adjacency protocol message. It is appended to all non-
           adjacency GSMP messages in the Ethernet encapsulation to
           offer additional protection against the introduction of
           corrupt state.
 Receiver Instance
           The Receiver Instance number is what the sender believes is
           the current instance number for the link, allocated by the
           entity at the far end of the link.  This field is already
           present in the adjacency protocol message. It is appended
           to all non-adjacency GSMP messages in the Ethernet
           encapsulation to offer additional protection against the
           introduction of corrupt state.
 Pad
           The minimum length of the data field of an Ethernet packet
           is 46 octets.  If necessary, padding should be added such
           that it meets the minimum Ethernet frame size. This padding
           should be octets of zero and it is not considered to be
           part of the GSMP message.
 After the adjacency protocol has achieved synchronization, for every
 GSMP message received with an Ethernet encapsulation, the receiver
 must check the Source Address from the Ethernet MAC header, the
 Sender Instance, and the Receiver Instance.  The incoming GSMP
 message must be discarded if the Sender Instance and the Source
 Address do not match the values of Sender Instance and Sender Name
 stored by the "Update Peer Verifier" operation of the GSMP adjacency
 protocol. The incoming GSMP message must also be discarded if it
 arrives over any port other than the port over which the adjacency
 protocol has achieved synchronization.  In addition, the incoming
 message must also be discarded if the Receiver Instance field does
 not match the current value for the Sender Instance of the GSMP
 adjacency protocol.

3. Common Definitions and Procedures

 GSMP is a master-slave protocol. The controller issues request
 messages to the switch. Each request message indicates whether a
 response is required from the switch and contains a transaction

Newman, et. al. Informational [Page 7] RFC 2297 Ipsilon's General Switch Management March 1998

 identifier to enable the response to be associated with the request.
 The switch replies with a response message indicating either a
 successful result or a failure. There are five classes of GSMP
 request-response message: Connection Management, Port Management,
 State and Statistics, Configuration, and Quality of Service.  The
 switch may also generate asynchronous Event messages to inform the
 controller of asynchronous events.  Event messages are not
 acknowledged by the controller. There is also an adjacency protocol
 message used to establish synchronization across the link and
 maintain a handshake.
 For the request-response messages, each message type has a format for
 the request message and a format for the success response.  Unless
 otherwise specified a failure response message is identical to the
 request message that caused the failure, with the Code field
 indicating the nature of the failure. Event messages have only a
 single format defined as they are not acknowledged by the controller.
 Switch ports are described by a 32-bit port number. The switch
 assigns port numbers and it may typically choose to structure the 32
 bits into subfields that have meaning to the physical structure of
 the switch (e.g. slot, port). In general, a port in the same physical
 location on the switch will always have the same port number, even
 across power cycles. The internal structure of the port number is
 opaque to the GSMP protocol. However, for the purposes of network
 management such as logging, port naming, and graphical
 representation, a switch may declare the physical location (physical
 slot and port) of each port. Alternatively, this information may be
 obtained by looking up the product identity in a database.
 Each switch port also maintains a port session number assigned by the
 switch. A message, with an incorrect port session number must be
 rejected.  This allows the controller to detect a link failure and to
 keep state synchronized.
 Except for the adjacency protocol message, no GSMP messages may be
 sent across the link until the adjacency protocol has achieved
 synchronization, and all GSMP messages received on a link that does
 not currently have state synchronization must be discarded.

3.1 GSMP Packet Format

 All GSMP messages, except the adjacency protocol message, have the
 following format:

Newman, et. al. Informational [Page 8] RFC 2297 Ipsilon's General Switch Management March 1998

  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 ~                          Message Body                         ~
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Version
           The version number of the GSMP protocol being used in this
           session. It should be set by the sender of the message to
           the GSMP protocol version negotiated by the adjacency
           protocol.
 Message Type
           The GSMP message type. GSMP messages fall into six classes:
           Connection Management, Port Management, State and
           Statistics, Configuration, Quality of Service, and Events.
           Each class has a number of different message types. In
           addition, one Message Type is allocated to the adjacency
           protocol.
 Result
           Field in a Connection Management request message, a Port
           Management request message, or a Quality of Service request
           message is used to indicate whether a response is required
           to the request message if the outcome is successful. A
           value of "NoSuccessAck" indicates that the request message
           does not expect a response if the outcome is successful,
           and a value of "AckAll" indicates that a response is
           expected if the outcome is successful.  In both cases a
           failure response must be generated if the request fails.
           For Sate and Statistics, and Configuration request
           messages, a value of "NoSuccessAck" in the request message
           is ignored and the request message is handled as if the
           field were set to "AckAll". (This facility was added to
           reduce the control traffic in the case where the controller
           periodically checks that the state in the switch is
           correct. If the controller does not use this capability,
           all request messages should be sent with a value of
           "AckAll.")

Newman, et. al. Informational [Page 9] RFC 2297 Ipsilon's General Switch Management March 1998

           In a response message the result field can have three
           values: "Success," "More," and "Failure". The "Success" and
           "More" results both indicate a success response. The "More"
           result indicates that the success response exceeds the
           maximum transmission unit of the data link and that one or
           more further messages will be sent to complete the success
           response. All messages that belong to the same success
           response will have the same Transaction Identifier. The
           "Success" result indicates a success response that may be
           contained in a single message or the final message of a
           success response spanning multiple messages.
           The encoding of the result field is:
                NoSuccessAck:  Result = 1
                AckAll:        Result = 2
                Success:       Result = 3
                Failure:       Result = 4
                More:          Result = 5.
           The Result field is not used in an adjacency protocol
           message.
 Code
           Field gives further information concerning the result in a
           response message. It is mostly used to pass an error code
           in a failure response but can also be used to give further
           information in a success response message or an event
           message. In a request message the code field is not used
           and is set to zero. In an adjacency protocol message the
           Code field is used to determine the function of the
           message.
 Transaction Identifier
           Used to associate a request message with its response
           message. For request messages the controller may select any
           transaction identifier. For response messages the
           transaction identifier is set to the value of the
           transaction identifier from the message to which it is a
           response.  For event messages the transaction identifier
           should be set to zero. The Transaction Identifier is not
           used, and the field is not present, in the adjacency
           protocol.
 The following fields are frequently found in GSMP messages. They are
 defined here to avoid repetition.

Newman, et. al. Informational [Page 10] RFC 2297 Ipsilon's General Switch Management March 1998

 Port
           Gives the port number of the switch port to which the
           message applies.
 Port Session Number
           Each switch port maintains a Port Session Number assigned
           by the switch. The port session number of a port remains
           unchanged while the port is continuously in the Available
           state and the link status is continuously Up. When a port
           returns to the Available state after it has been
           Unavailable or in any of the Loopback states, or when the
           line status returns to the Up state after it has been Down
           or in Test, or after a power cycle, a new Port Session
           Number must be generated.  Port session numbers should be
           assigned using some form of random number.
           If the Port Session Number in a request message does not
           match the current Port Session Number for the specified
           port, a failure response message must be returned with the
           Code field indicating, "Invalid port session number."  The
           current port session number for a port may be obtained
           using a Port Configuration or an All Ports Configuration
           message.
 Any field in a GSMP message that is unused or defined as "reserved"
 must be set to zero by the sender and ignored by the receiver.
 It is not an error for a GSMP message to contain additional data
 after the end of the Message Body. This is to support development and
 experimental purposes. However, the maximum transmission unit of the
 GSMP message, as defined by the data link layer encapsulation, must
 not be exceeded.
 A success response message must not be sent until the requested
 operation has been successfully completed.

3.2 Failure Response Messages

 A failure response message is formed by returning the request message
 that caused the failure with the Result field in the header
 indicating failure (Result = 4) and the Code field giving the failure
 code. The failure code specifies the reason for the switch being
 unable to satisfy the request message.
 If the switch issues a failure response in reply to a request
 message, no change should be made to the state of the switch as a
 result of the message causing the failure. (For request messages that
 contain multiple requests, such as the Delete Branches message, the

Newman, et. al. Informational [Page 11] RFC 2297 Ipsilon's General Switch Management March 1998

 failure response message will specify which requests were successful
 and which failed. The successful requests may result in changed
 state.)
 If the switch issues a failure response it must choose the most
 specific failure code according to the following precedence:
     Invalid Message
     Failure specific to the particular message type (failure code
         16). (The meaning of this failure is dependent upon the
         particular message type and is specified in the text defining
         the message.)
     A failure response specified in the text defining the message
         type.
     Connection Failures
     Virtual Path Connection Failures
     Multicast Failures
     QoS Failures (QoS failures are specified in Section 9.7.)
     General Failures
 If multiple failures match in any of the following categories, the
 one that is listed first should be returned. The following failure
 response messages and failure codes are defined:
 Invalid Message
     3:  The specified request is not implemented on this switch.
             The Message Type field specifies a message that is not
             implemented on the switch or contains a value that is not
             defined in the version of the protocol running in this
             session of GSMP.
     5:  One or more of the specified ports does not exist.
             At least one of the ports specified in the message is
             invalid. A port is invalid if it does not exist or if it
             has been removed from the switch.
     4:  Invalid Port Session Number.
             The value given in the Port Session Number field does not
             match the current Port Session Number for the specified
             port.

Newman, et. al. Informational [Page 12] RFC 2297 Ipsilon's General Switch Management March 1998

 Connection Failures
     8:  The specified connection does not exist.
             An operation that expects a connection to be specified,
             either a virtual channel or a virtual path connection,
             cannot locate the specified connection. A virtual channel
             connection is specified by the input port, input VPI, and
             input VCI on which it arrives. A virtual path connection
             is specified by the input port and input VPI on which it
             arrives.
     9:  The specified branch does not exist.
             An operation that expects a branch of an existing
             connection to be specified, either a virtual channel or a
             virtual path connection, cannot locate the specified
             branch.  A branch of a virtual channel connection is
             specified by the virtual channel connection it belongs to
             and the output port, output VPI, and output VCI on which
             it departs. A branch of a virtual path connection is
             specified by the virtual path connection it belongs to
             and the output port and output VPI on which it departs.
     18: One or more of the specified input VPIs is invalid.
     19: One or more of the specified input VCIs is invalid.
     20: One or more of the specified output VPIs is invalid.
     21: One or more of the specified output VCIs is invalid.
     22: Invalid Class of Service field in a Connection Management
             message.
             The value of the Class of Service field is invalid.
     23: Insufficient resources for QoS Profile.
             The resources requested by the QoS Profile in the Class
             of service field are not available.
 Virtual Path Connections
     24: Virtual path switching is not supported on this input port.
     25: Point-to-multipoint virtual path connections are not
             supported on either the requested input port or the
             requested output port.
             One or both of the requested input and output ports is
             unable to support point-to-multipoint virtual path
             connections.

Newman, et. al. Informational [Page 13] RFC 2297 Ipsilon's General Switch Management March 1998

     26: Attempt to add a virtual path connection branch to an
             existing virtual channel connection.
             It is invalid to mix branches switched as virtual channel
             connections with branches switched as virtual path
             connections on the same point-to-multipoint connection.
     27: Attempt to add a virtual channel connection branch to an
             existing virtual path connection.
             It is invalid to mix branches switched as virtual channel
             connections with branches switched as virtual path
             connections on the same point-to-multipoint connection.
 Multicast Failures
     10: A branch belonging to the specified point-to-multipoint
             connection is already established on the specified output
             port and the switch cannot support more than a single
             branch of any point-to-multipoint connection on the same
             output port.
     11: The limit on the maximum number of point-to-multipoint
             connections that the switch can support has been reached.
     12: The limit on the maximum number of branches that the
             specified point-to-multipoint connection can support has
             been reached.
     17: Cannot label each output branch of a point-to-multipoint tree
             with a different label.
             Some early designs, and some low-cost ATM switch designs,
             require all output branches of a multicast connection to
             use the same value of VPI/VCI.
     28: Only point-to-point bidirectional connections may be
             established.
             It is an error to attempt to add an additional output
             branch to an existing connection with the bidirectional
             flag set.
     13: Unable to assign the requested VPI/VCI value to the requested
             branch on the specified point-to-multipoint connection.
             Although the requested VPI and VCI are valid, the switch
             is unable to support the request using the specified
             values of VPI and VCI for some reason not covered by the
             above failure responses. This message implies that a
             valid value of VPI or VCI exists that the switch could

Newman, et. al. Informational [Page 14] RFC 2297 Ipsilon's General Switch Management March 1998

             support. For example, some switch designs restrict the
             number of distinct VPI/VCI values available to a point-
             to-multipoint connection. (Most switch designs will not
             require this message.)
     14: General problem related to the manner in which point-to-
             multipoint is supported by the switch.
             Use this message if none of the more specific multicast
             failure messages apply.  (Most switch designs will not
             require this message.)
 General Failures
     2:  Invalid request message.
             There is an error in one of the fields of the message not
             covered by a more specific failure message.
     6:  One or more of the specified ports is down.
             A port is down if its Port Status is Unavailable.
             Connection Management, Connection State, Port Management,
             and Configuration operations are permitted on a port that
             is Unavailable. Connection Activity and Statistics
             operations are not permitted on a port that is
             Unavailable and will generate this failure response. A
             Port Management message specifying a Take Down function
             on a port already in the Unavailable state will also
             generate this failure response.
     15: Out of resources.
             The switch has exhausted a resource not covered by a more
             specific failure message, for example, running out of
             memory.
     1:  Unspecified reason not covered by other failure codes.
             The failure message of last resort.
 The following failure response messages are only used by the Label
             Range message.
     29: Cannot support requested VPI range.
     30: Cannot support requested VCI range on all requested VPIs.
 The following failure response messages are only used by the Set
             Transmit Cell Rate function of the Port Management
             message.
     31: The transmit cell rate of this output port cannot be changed.

Newman, et. al. Informational [Page 15] RFC 2297 Ipsilon's General Switch Management March 1998

     32: Requested transmit cell rate out of range for this output
             port.

4. Connection Management Messages

 Connection management messages are used by the controller to
 establish, delete, modify and verify virtual channel connections and
 virtual path connections across the switch. The Add Branch, Delete
 Tree, and Delete All connection management messages have the
 following format for both request and response messages:
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      Port Session Number                      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                          Input Port                           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |M|Q|B|C|      Input VPI        |          Input VCI            |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                          Output Port                          |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |x x x x|      Output VPI       |          Output VCI           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |      Number of Branches       |       Class of Service        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Input Port
           Identifies a switch input port.
 Flags
      M: Multicast
           The Multicast flag is used as a hint for point-to-
           multipoint connections in the Add Branch message. It is not
           used in any other connection management messages and in
           these messages it should be set to zero. If set, it
           indicates that the virtual channel connection or the
           virtual path connection is very likely to be a point-to-
           multipoint connection. If zero, it indicates that this
           connection is very likely to be a point-to-point connection
           or is unknown.

Newman, et. al. Informational [Page 16] RFC 2297 Ipsilon's General Switch Management March 1998

           The Multicast flag is only used in the Add Branch message
           when establishing the first branch of a new connection. It
           is not required to be set when establishing subsequent
           branches of a point-to-multipoint connection and on such
           connections it should be ignored by the receiver. (On
           receipt of the second and subsequent Add Branch messages
           the receiver knows that this is a point-to-multipoint
           connection.) If it is known that this is the first branch
           of a point-to-multipoint connection this flag should be
           set. If it is unknown, or if it is known that the
           connection is point-to-point this flag should be zero. The
           use of this flag is not mandatory. It may be ignored by the
           switch.  If unused the flag should be set to zero. Some
           switches use a different data structure for point-to-
           multipoint connections than for point-to-point connections.
           This flag avoids the switch setting up a point-to-point
           structure for the first branch of a point-to-multipoint
           connection which must immediately be deleted and
           reconfigured as point-to-multipoint when the second branch
           is established.
      Q: QoS Profile
           The QoS Profile flag, if set, indicates that the Class of
           Service field contains a QoS Profile Identifier.  If this
           flag is zero, it indicates that the Class of Service field
           contains a Priority or a Scheduler Identifier.
      B: Bidirectional
           The Bidirectional flag applies only to the Add Branch
           message. In all other Connection Management messages it is
           not used. It may only be used when establishing a point-
           to-point connection.  The Bidirectional flag in an Add
           Branch message, if set, requests that two unidirectional
           virtual channels or virtual paths be established, one in
           the forward direction, and one in the reverse direction. It
           is equivalent to two Add Branch messages, one specifying
           the forward direction, and one specifying the reverse
           direction. The forward direction uses the values of Input
           Port, Input VPI, Input VCI, Output Port, Output VPI, and
           Output VCI as specified in the Add Branch message. The
           reverse direction is derived by exchanging the values
           specified in the Input Port, Input VPI, and Input VCI
           fields, with those of the Output Port, Output VPI, and
           Output VCI fields respectively. Thus, a virtual connection
           in the reverse direction arrives at the input port
           specified by the Output Port field, on the VPI/VCI
           specified by the Output VPI and Output VCI fields. It
           departs from the output port specified by the Input Port

Newman, et. al. Informational [Page 17] RFC 2297 Ipsilon's General Switch Management March 1998

           field, on the VPI/VCI specified by the Input VPI and Input
           VCI fields.
           The Bidirectional flag is simply a convenience to establish
           two unidirectional virtual connections in opposite
           directions between the same two ports, with identical
           VPI/VCIs, using a single Add Branch message. In all future
           messages the two unidirectional virtual connections must be
           handled separately. There is no bidirectional delete
           message. However, a single Delete Branches message with two
           Delete Branch Elements, one for the forward connection and
           one for the reverse, may be used.
      C: Congestion Indication
           The Congestion Indication flag, if set, requests that cells
           on this connection be marked if congestion is experienced.
           If this connection passes through a queue that the switch
           considers to be congested, the Congestion Experienced bit
           will be set in the Payload Type field of the cell header of
           all cells on the connection. GSMP does not specify the
           algorithm or any threshold by which the switch decides when
           a queue is congested.
 Input VPI
           Identifies an ATM virtual path arriving at the switch input
           port indicated by the Input Port field.
 Input VCI
           Identifies an ATM virtual channel arriving on the virtual
           path indicated by the Input VPI field at the switch input
           port indicated by the Input Port field. For virtual path
           connections the Input VCI field is not used.
 Output Port
           Identifies a switch output port.
 x: Unused
 Output VPI
           Identifies an outgoing virtual path departing from the
           switch output port indicated in the Output Port field.
 Output VCI
           Identifies an outgoing virtual channel departing on the
           virtual path indicated by the Output VPI field from the
           switch output port indicated in the Output Port field. For
           virtual path connections the Output VCI field is not used.

Newman, et. al. Informational [Page 18] RFC 2297 Ipsilon's General Switch Management March 1998

 Number of Branches
           In a success response message and a failure response
           message, gives the number of output branches on a virtual
           channel connection or a virtual path connection after
           completion of the requested operation.  (A point-to-point
           connection will have one branch, a point-to-multipoint
           connection will have two or more branches.) If the switch
           is unable to keep track of the number of branches on a
           virtual path connection or a virtual channel connection it
           must respond with the value 0xFFFF meaning: "number of
           branches unknown".  This field is not used in the request
           message.
 Class of Service
           This field can contain either a QoS Profile Identifier, a
           Priority, or a Scheduler Identifier.  If the QoS Profile
           flag in the Flags field is set, the Class of Service field
           contains a QoS Profile.  If the QoS Profile flag in the
           Flags field is zero, and the value of the Class of Service
           field is greater than or equal to 0x100, the Class of
           Service field contains a Scheduler Identifier.  If the QoS
           Profile flag in the Flags field is zero, and the value of
           the Class of Service field is less than 0x100, the Class of
           Service field contains a Priority. (Values of Scheduler
           Identifier less than 0x100 are interpreted as priorities.)
           The Class of Service field is only used in the Add Branch
           and Move Branch messages.
           A QoS Profile Identifier is an opaque 16-bit value. It is
           used to identify a QoS profile in the switch which
           specifies the Quality of Service required by the
           connection. QoS profiles are established by a mechanism
           external to GSMP.
           A Scheduler Identifier is an alternative method of
           communicating the QoS requirements of a connection. The
           Scheduler Identifier is defined in Section 9, "Quality of
           Service Messages."
           A Priority specifies the priority of the connection for Add
           Branch and Move Branch messages that choose not to use a
           QoS profile, or the QoS capabilities defined in Section 9,
           "Quality of Service Messages." The highest priority is
           numbered zero and the lowest priority is numbered "Q-1"
           where "Q" is the number of priorities that the output port
           can support. The ability to offer different qualities of
           service to different connections based upon their priority
           is assumed to be a property of the output port of the

Newman, et. al. Informational [Page 19] RFC 2297 Ipsilon's General Switch Management March 1998

           switch. It is assumed that for virtual path connections or
           virtual channel connections that share the same output
           port, an ATM cell on a connection with a higher priority is
           much more likely to exit the switch before an ATM cell on a
           connection with a lower priority, if they are both in the
           switch at the same time. The number of priorities that each
           output port can support is given in the Port Configuration
           message.
 For all connection management messages, except the Delete Branches
 message, the success response message is a copy of the request
 message returned with the Result field indicating success and the
 Number of Branches field indicating the number of branches on the
 connection after completion of the operation. The Code field is not
 used in a connection management success response message.
 The failure response message is a copy of the request message
 returned with a Result field indicating failure and the Number of
 Branches field indicating the number of branches on the connection.
 Fundamentally, no distinction is made between point-to-point and
 point-to-multipoint connections. By default, the first Add Branch
 message for a particular Input Port, Input VPI, and Input VCI will
 establish a point-to-point virtual connection.  The second Add Branch
 message with the same Input Port, Input VPI, and Input VCI fields
 will convert the connection to a point-to-multipoint virtual
 connection with two branches. (For virtual path connections the Input
 VCI is not required.) However, to avoid possible inefficiency with
 some switch designs, the Multicast Flag is provided. If the
 controller knows that a new connection is point-to-multipoint when
 establishing the first branch, it may indicate this in the Multicast
 Flag.  Subsequent Add Branch messages with the same Input Port, Input
 VPI, and Input VCI fields will add further branches to the point-to-
 multipoint connection. Use of the Delete Branch message on a point-
 to-multipoint connection with two branches will result in a point-
 to-point connection. However, the switch may structure this
 connection as a point-to-multipoint connection with a single output
 branch if it chooses. (For some switch designs this structure may be
 more convenient.) Use of the Delete Branch message on a point-to-
 point connection will delete the point-to-point connection. There is
 no concept of a connection with zero output branches. All connections
 are unidirectional, one input virtual path or virtual channel to one
 or more output virtual paths or virtual channels.
 GSMP supports point-to-point and point-to-multipoint connections. A
 multipoint-to-point connection is specified by establishing multiple
 point-to-point connections each of them specifying the same output
 branch.  (An output branch is specified by an output port and output

Newman, et. al. Informational [Page 20] RFC 2297 Ipsilon's General Switch Management March 1998

 VPI for a virtual path connection and by an output port, output VPI,
 and output VCI for a virtual channel connection.) A multipoint-to-
 multipoint connection is specified by establishing multiple point-
 to-multipoint trees each of them specifying the same output branches.
 The connection management messages apply both to virtual channel
 connections and virtual path connections. The Add Branch and Move
 Branch connection management messages have two Message Types. One
 Message Type indicates that a virtual channel connection is required,
 and the other Message Type indicates that a virtual path connection
 is required. The Delete Branches, Delete Tree, and Delete All
 connection management messages have only a single Message Type
 because they do not need to distinguish between virtual channel
 connections and virtual path connections. For virtual path
 connections, neither Input VCI fields nor Output VCI fields are
 required. They should be set to zero by the sender and ignored by the
 receiver. Virtual channel branches may not be added to an existing
 virtual path connection.  Conversely, virtual path branches may not
 be added to an existing virtual channel connection.  In the Port
 Configuration message each switch input port may declare whether it
 is capable of supporting virtual path switching (i.e. accepting
 connection management messages requesting virtual path connections).
 The connection management messages may be issued regardless of the
 Port Status of the switch port. Connections may be established or
 deleted when a switch port is in the Available, Unavailable, or any
 of the Loopback states. However, all connection state on an input
 port will be deleted when the port returns to the Available state
 from any other state, i.e. when a Port Management message is received
 for that port with the Function field indicating either Bring Up, or
 Reset Input Port.

4.1 Add Branch Message

 The Add Branch message is a connection management message used to
 establish a virtual channel connection or a virtual path connection
 or to add an additional branch to an existing virtual channel
 connection or virtual path connection. It may also be used to check
 the connection state stored in the switch. The connection is
 specified by the Input Port, Input VPI, and Input VCI fields. The
 output branch is specified by the Output Port, Output VPI, and Output
 VCI fields. The quality of service requirements of the connection are
 specified by the Class of Service field. To request a virtual channel
 connection the Virtual Channel Connection (VCC) Add Branch message
 is:
    Message Type = 16

Newman, et. al. Informational [Page 21] RFC 2297 Ipsilon's General Switch Management March 1998

 To request a virtual path connection the Virtual Path Connection
 (VPC) Add Branch message is:
    Message Type = 26
 If a VPC Add Branch message is received and the switch input port
 specified by the Input Port field does not support virtual path
 switching, a failure response message must be returned indicating,
 "Virtual path switching is not supported on this input port."
 If the virtual channel connection specified by the Input Port, Input
 VPI, and Input VCI fields; or the virtual path connection specified
 by the Input Port and Input VPI fields; does not already exist, it
 must be established with the single output branch specified in the
 request message. If the Bidirectional Flag in the Flags field is set,
 the reverse connection must also be established.  The output branch
 should have the QoS attributes specified by the Class of Service
 field.
 For the VCC Add Branch message, if a virtual path connection already
 exists on the virtual path specified by the Input Port and Input VPI
 fields, a failure response message must be returned indicating,
 "Attempt to add a virtual channel connection branch to an existing
 virtual path connection." For the VPC Add Branch message, if a
 virtual channel connection already exists on any of the virtual
 channels within the virtual path specified by the Input Port and
 Input VPI fields, a failure response message must be returned
 indicating, "Attempt to add a virtual path connection branch to an
 existing virtual channel connection."
 If the virtual channel connection specified by the Input Port, Input
 VPI, and Input VCI fields; or the virtual path connection specified
 by the Input Port and Input VPI fields; already exists, but the
 specified output branch does not, the new output branch must be
 added.  The new output branch should have the QoS attributes
 specified by the Class of Service field.
 If the virtual channel connection specified by the Input Port, Input
 VPI, and Input VCI fields; or the virtual path connection specified
 by the Input Port and Input VPI fields; already exists and the
 specified output branch also already exists, the QoS attributes of
 the connection, specified by the Class of Service field, if different
 from the request message, should be changed to that in the request
 message.  A success response message must be sent if the Result field
 of the request message is "AckAll".  This allows the controller to
 periodically reassert the state of a connection or to change its
 priority. If the result field of the request message is
 "NoSuccessAck" a success response message should not be returned.

Newman, et. al. Informational [Page 22] RFC 2297 Ipsilon's General Switch Management March 1998

 This may be used to reduce the traffic on the control link for
 messages that are reasserting previously established state. For
 messages that are reasserting previously established state, the
 switch must always check that this state is correctly established in
 the switch hardware (i.e. the actual connection tables used to
 forward cells).
 If the output branch specified by the Output Port, Output VPI, and
 Output VCI fields for a virtual channel connection; or the output
 branch specified by the Output Port and Output VPI fields for a
 virtual path connection; is already in use by any connection other
 than that specified by the Input Port, Input VPI, and Input VCI
 fields, then the resulting output branch will have multiple input
 branches. If multiple point-to-point connections share the same
 output branch the result will be a multipoint-to-point connection. If
 multiple point-to-multipoint trees share the same output branches the
 result will be a multipoint-to-multipoint connection.
 If the virtual channel connection specified by the Input Port, Input
 VPI, and Input VCI fields, or the virtual path connection specified
 by the Input Port and Input VPI fields, already exists, and the
 Bidirectional Flag in the Flags field is set, a failure response must
 be returned indicating: "Only point-to-point bidirectional
 connections may be established."
 It should be noted that different switches support multicast in
 different ways. There will be a limit to the total number of point-
 to-multipoint connections any switch can support, and possibly a
 limit on the maximum number of branches that a point-to-multipoint
 connection may specify.  Some switches also impose a limit on the
 number of different VPI/VCI values that may be assigned to the output
 branches of a point-to-multipoint connection. Many switches are
 incapable of supporting more than a single branch of any particular
 point-to-multipoint connection on the same output port. Specific
 failure codes are defined for some of these conditions.

4.2 Delete Tree Message

 The Delete Tree message is a connection management message used to
 delete an entire virtual channel connection or an entire virtual path
 connection. All remaining branches of the connection are deleted. A
 virtual channel connection is specified by the Input Port, Input VPI,
 and Input VCI fields. A virtual path connection is specified by the
 Input Port and Input VPI fields. The Output Port, Output VPI, and
 Output VCI fields are not used in this message. The Delete Tree
 message is:
    Message Type = 18

Newman, et. al. Informational [Page 23] RFC 2297 Ipsilon's General Switch Management March 1998

 If the Result field of the request message is "AckAll" a success
 response message must be sent upon successful deletion of the
 specified connection. The success message must not be sent until the
 delete operation has been completed and if possible, not until all
 data on the connection, queued for transmission, has been
 transmitted. The Number of Branches field is not used in either the
 request or response messages of the Delete Tree message.

4.3 Verify Tree Message

 The Verify Tree message has been removed from this version of GSMP.
 Its function has been replaced by the Number of Branches field in the
 success response to the Add Branch message which contains the number
 of branches on a virtual channel connection after successful
 completion of an add branch operation.
    Message Type = 19 is reserved.
 If a request message is received with Message Type = 19 a failure
 response must be returned with the Code field indicating: "The
 specified request is not implemented in this version of the
 protocol."

4.4 Delete All Message

 The Delete All message is a connection management message used to
 delete all connections on a switch input port. All connections that
 arrive at the specified input port must be deleted. On completion of
 the operation all dynamically assigned VPI/VCI values for the
 specified port must be unassigned, i.e. there must be no virtual
 connections established in the VPI/VCI space that GSMP controls on
 this port. The Input VPI, Input VCI, Output Port, Output VPI, and
 Output VCI fields are not used in this message.  The Delete All
 message is:
    Message Type = 20
 If the Result field of the request message is "AckAll" a success
 response message must be sent upon completion of the operation. The
 Number of Branches field is not used in either the request or
 response messages of the Delete All message.  The success response
 message must not be sent until the operation has been completed.
 The following failure response messages may be returned to a Delete
 All request.
       The specified request is not implemented on this switch.

Newman, et. al. Informational [Page 24] RFC 2297 Ipsilon's General Switch Management March 1998

       One or more of the specified ports does not exist.
       Invalid Port Session Number.
 If any field in a Delete All message not covered by the above failure
 codes is invalid, a failure response must be returned indicating:
 "Invalid request message." Else, the delete all operation must be
 completed successfully and a success message returned. No other
 failure messages are permitted.

4.5 Delete Branches Message

 The Delete Branches message is a connection management message used
 to request one or more delete branch operations. Each delete branch
 operation deletes a branch of a virtual channel connection or a
 virtual path connection, or in the case of the last branch of a
 connection, it deletes the connection. The Delete Branches message
 is:
    Message Type = 17
 The request message has the following format:
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |           Reserved            |      Number of Elements       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 ~                    Delete Branch Elements                     ~
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Number of Elements
           Specifies the number of Delete Branch Elements to follow in
           the message. The number of Delete Branch Elements in a
           Delete Branches message must not cause the packet length to
           exceed the maximum transmission unit defined by the
           encapsulation.
 Each Delete Branch Element specifies an output branch to be deleted
 and has the following structure:

Newman, et. al. Informational [Page 25] RFC 2297 Ipsilon's General Switch Management March 1998

 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      Port Session Number                      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                          Input Port                           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | Error |      Input VPI        |          Input VCI            |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                          Output Port                          |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |x x x x|      Output VPI       |          Output VCI           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Error
           Is used to return a failure code indicating the reason for
           the failure of a specific Delete Branch Element in a Delete
           Branches failure response message.  The Error field is not
           used in the request message and must be set to zero.  A
           value of zero is used to indicate that the delete operation
           specified by this Delete Branch Element was successful.
           Values for the other failure codes are specified in Section
           3.2, "Failure Response Messages."
           All other fields of the Delete Branch Element have the same
           definition as specified for the other connection management
           messages.
 In each Delete Branch Element, either a virtual channel connection is
 specified by the Input Port, Input VPI, and Input VCI fields; or a
 virtual path connection is specified by the Input Port and Input VPI
 fields. The specific branch to be deleted is indicated by the Output
 Port, Output VPI, and Output VCI fields for virtual channel
 connections and by the Output Port and Output VPI for virtual path
 connections.
 If the Result field of the Delete Branches request message is
 "AckAll" a success response message must be sent upon successful
 deletion of the branches specified by all of the Delete Branch
 Elements. The success response message must not be sent until all of
 the delete branch operations have been completed. The success
 response message is only sent if all of the requested delete branch
 operations were successful. No Delete Branch Elements are returned in
 a Delete Branches success response message and the Number of Elements
 field must be set to zero.
 If there is a failure in any of the Delete Branch Elements a Delete
 Branches failure response message must be returned. The Delete
 Branches failure response message is a copy of the request message
 with the Code field of the entire message set to, "Failure specific

Newman, et. al. Informational [Page 26] RFC 2297 Ipsilon's General Switch Management March 1998

 to the particular message type," and the Error field of each Delete
 Branch Element indicating the result of each requested delete
 operation. A failure in any of the Delete Branch Elements must not
 interfere with the processing of any other Delete Branch Elements.

4.6 Move Branch Message

 The Move Branch message is used to move a branch of an existing
 connection from its current output port VPI/VCI to a new output port
 VPI/VCI in a single atomic transaction. This operation occurs
 frequently in IP switching, every time a flow is switched from hop-
 by-hop forwarding to a dedicated virtual channel.  The Move Branch
 connection management message has the following format for both
 request and response messages:
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      Port Session Number                      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                           Input Port                          |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | Flags |        Input VPI      |           Input VCI           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                        Old Output Port                        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |x x x x|    Old Output VPI     |        Old Output VCI         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                        New Output Port                        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |x x x x|    New Output VPI     |        New Output VCI         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Number of Branches      |       Class of Service        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 The VCC Move Branch message is a connection management message used
 to move a single output branch of a virtual channel connection from
 its current output port, output VPI, and output VCI, to a new output
 port, output VPI, and output VCI on the same virtual channel
 connection. None of the other output branches are modified.  When the
 operation is complete the original output VPI/VCI on the original
 output port will be deleted from the connection.  The VCC Move Branch
 message is:

Newman, et. al. Informational [Page 27] RFC 2297 Ipsilon's General Switch Management March 1998

    Message Type = 22
 For the VCC Move Branch message, if the virtual channel connection
 specified by the Input Port, Input VPI, and Input VCI fields already
 exists, and the output branch specified by the Old Output Port, Old
 Output VPI, and Old Output VCI fields exists as a branch on that
 connection, the output branch specified by the New Output Port, New
 Output VPI, and New Output VCI fields is added to the connection and
 the branch specified by the Old Output Port, Old Output VPI, and Old
 Output VCI fields is deleted. If the Result field of the request
 message is "AckAll" a success response message must be sent upon
 successful completion of the operation. The success response message
 must not be sent until the Move Branch operation has been completed.
 For the VCC Move Branch message, if the virtual channel connection
 specified by the Input Port, Input VPI, and Input VCI fields already
 exists, but the output branch specified by the Old Output Port, Old
 Output VPI, and Old Output VCI fields does not exist as a branch on
 that connection, a failure response must be returned with the Code
 field indicating, "The specified branch does not exist."
 The VPC Move Branch message is a connection management message used
 to move a single output branch of a virtual path connection from its
 current output port and output VPI, to a new output port and output
 VPI on the same virtual channel connection. None of the other output
 branches are modified.  When the operation is complete the original
 output VPI on the original output port will be deleted from the
 connection.  The VPC Move Branch message is:
    Message Type = 27
 For the VPC Move Branch message, if the virtual path connection
 specified by the Input Port and Input VPI fields already exists, and
 the output branch specified by the Old Output Port and Old Output VPI
 fields exists as a branch on that connection, the output branch
 specified by the New Output Port and New Output VPI fields is added
 to the connection and the branch specified by the Old Output Port and
 Old Output VPI fields is deleted. If the Result field of the request
 message is "AckAll" a success response message must be sent upon
 successful completion of the operation. The success response message
 must not be sent until the Move Branch operation has been completed.
 For the VPC Move Branch message, if the virtual path connection
 specified by the Input Port and Input VPI fields already exists, but
 the output branch specified by the Old Output Port and Old Output VPI
 fields does not exist as a branch on that connection, a failure
 response must be returned with the Code field indicating, "The
 specified branch does not exist."

Newman, et. al. Informational [Page 28] RFC 2297 Ipsilon's General Switch Management March 1998

 If the virtual channel connection specified by the Input Port, Input
 VPI, and Input VCI fields; or the virtual path connection specified
 by the Input Port and  Input VPI fields; does not exist, a failure
 response must be returned with the Code field indicating, "The
 specified connection does not exist."
 If the output branch specified by the New Output Port, New Output
 VPI, and New Output VCI fields for a virtual channel connection; or
 the output branch specified by the New Output Port and New Output VPI
 fields for a virtual path connection; is already in use by any
 connection other than that specified by the Input Port, Input VPI,
 and Input VCI fields then the resulting output branch will have
 multiple input branches. If multiple point-to-point connections share
 the same output branch the result will be a multipoint-to-point
 connection. If multiple point-to-multipoint trees share the same
 output branches the result will be a multipoint-to-multipoint
 connection.

5. Port Management Messages

5.1 Port Management Message

 The Port Management message allows a port to be brought into service,
 taken out of service, looped back, reset, or the transmit cell rate
 changed.  Only the Bring Up and the Reset Input Port functions change
 the connection state (established connections) on the input port.
 Only the Bring Up function changes the value of the Port Session
 Number. If the Result field of the request message is "AckAll" a
 success response message must be sent upon successful completion of
 the operation. The success response message must not be sent until
 the operation has been completed. The Port Management Message is:
    Message Type = 32
 The Port Management message has the following format for the request
 and success response messages:

Newman, et. al. Informational [Page 29] RFC 2297 Ipsilon's General Switch Management March 1998

  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                             Port                              |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      Port Session Number                      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                     Event Sequence Number                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |  Event Flags  |   Duration    |          Function             |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      Transmit Cell Rate                       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Event Sequence Number
           In the success response message gives the current value of
           the Event Sequence Number of the switch port indicated by
           the Port field. The Event Sequence Number is set to zero
           when the port is initialized. It is incremented by one each
           time the port detects an asynchronous event that the switch
           would normally report via an Event message. If the Event
           Sequence Number in the success response differs from the
           Event Sequence Number of the most recent Event message
           received for that port, events have occurred that were not
           reported via an Event message. This is most likely to be
           due to the flow control that restricts the rate at which a
           switch can send Event messages for each port. In the
           request message this field is not used.
 Event Flags
           Field in the request message is used to reset the Event
           Flags in the switch port indicated by the Port field. Each
           Event Flag in a switch port corresponds to a type of Event
           message. When a switch port sends an Event message it sets
           the corresponding Event Flag on that port. The port is not
           permitted to send another Event message of the same type
           until the Event Flag has been reset. If the Function field
           in the request message is set to "Reset Event Flags," for
           each bit that is set in the Event Flags field, the
           corresponding Event Flag in the switch port is reset.
           The Event Flags field is only used in a request message
           with the Function field set to "Reset Event Flags." For all
           other values of the Function field, the Event Flags field

Newman, et. al. Informational [Page 30] RFC 2297 Ipsilon's General Switch Management March 1998

           is not used.  In the success response message the Event
           Flags field must be set to the current value of the Event
           Flags for the port, after the completion of the operation
           specified by the request message, for all values of the
           Function field. Setting the Event Flags field to all zeros
           in a "Reset Event Flags" request message allows the
           controller to obtain the current state of the Event Flags
           and the current Event Sequence Number of the port without
           changing the state of the Event Flags.
           The correspondence between the types of Event message and
           the bits of the Event Flags field is as follows:
               0 1 2 3 4 5 6 7
              +-+-+-+-+-+-+-+-+
              |U|D|I|N|Z|x x x|
              +-+-+-+-+-+-+-+-+
              U: Port Up          Bit 0, (most significant bit)
              D: Port Down        Bit 1,
              I: Invalid VPI/VCI  Bit 2,
              N: New Port         Bit 3,
              Z: Dead Port        Bit 4,
              x: Unused           Bits 5--7.
 Duration
           Is the length of time, in seconds, that any of the loopback
           states remain in operation. When the duration has expired
           the port will automatically be returned to service.  If
           another Port Management message is received for the same
           port before the duration has expired, the loopback will
           continue to remain in operation for the length of time
           specified by the Duration field in the new message. The
           Duration field is only used in request messages with the
           Function field set to Internal Loopback, External Loopback,
           or Bothway Loopback.
 Function
           Specifies the action to be taken. The specified action will
           be taken regardless of the current status of the port
           (Available, Unavailable, or any Loopback state).  If the
           specified function requires a new Port Session Number to be
           generated, the new Port Session Number must be returned in
           the success response message.  The defined values of the
           Function field are:
           Bring Up:
                Function = 1. Bring the port into service. All

Newman, et. al. Informational [Page 31] RFC 2297 Ipsilon's General Switch Management March 1998

                connections that arrive at the specified input port
                must be deleted and a new Port Session Number must be
                selected using some form of random number. On
                completion of the operation all dynamically assigned
                VPI/VCI values for the specified input port must be
                unassigned, i.e. no virtual connections will be
                established in the VPI/VCI space that GSMP controls on
                this input port. The Port Status of the port
                afterwards will be Available.
           Take Down:
                Function = 2. Take the port out of service. Any cells
                received at this port will be discarded. No cells will
                be transmitted from this port. The Port Status of the
                port afterwards will be Unavailable.
                The behavior is undefined if the port is taken down
                over which the GSMP session that controls the switch
                is running. (In this case the most probable behavior
                would be for the switch either to ignore the message
                or to terminate the current GSMP session and to
                initiate another session, possibly with the backup
                controller, if any.) The correct method to reset the
                link over which GSMP is running is to issue an RSTACK
                message in the adjacency protocol.
           Internal Loopback:
                Function = 3. Cells arriving at the output port from
                the switch fabric are looped through to the input port
                to return to the switch fabric. All of the ATM
                functions of the input port above the physical layer,
                e.g. header translation, are performed upon the looped
                back cells. The Port Status of the port afterwards
                will be Internal Loopback.
           External Loopback:
                Function = 4. Cells arriving at the input port from
                the external communications link are immediately
                looped back to the communications link at the physical
                layer without entering the input port. None of the ATM
                functions of the input port above the physical layer
                are performed upon the looped back cells. The Port
                Status of the port afterwards will be External
                Loopback.
           Bothway Loopback:
                Function = 5. Both internal and external loopback are

Newman, et. al. Informational [Page 32] RFC 2297 Ipsilon's General Switch Management March 1998

                performed. The Port Status of the port afterwards will
                be Bothway Loopback.
           Reset Input Port:
                Function = 6. All connections that arrive at the
                specified input port must be deleted and the input and
                output port hardware re-initialized. On completion of
                the operation all dynamically assigned VPI/VCI values
                for the specified input port must be unassigned, i.e.
                no virtual connections will be established in the
                VPI/VCI space that GSMP controls on this input port.
                The range of VPIs and VCIs that may be controlled by
                GSMP on this port will be set to the default values
                specified in the Port Configuration message.  The
                transmit cell rate of the output port must be set to
                its default value. The Port Session Number is not
                changed by the Reset Input Port function.  The Port
                Status of the port afterwards will be Unavailable.
           Reset Event Flags:
                Function = 7. For each bit that is set in the Event
                Flags field, the corresponding Event Flag in the
                switch port must be reset. The Port Status of the port
                is not changed by this function.
           Set Transmit Cell Rate:
                Function = 8. Sets the transmit cell rate of the
                output port as close as possible to the rate specified
                in the Transmit Cell Rate field. In the success
                response message the Transmit Cell Rate must indicate
                the actual transmit cell rate of the output port.  If
                the transmit cell rate of the requested output port
                cannot be changed, a failure response must be returned
                with the Code field indicating: "The transmit cell
                rate of this output port cannot be changed." If the
                transmit cell rate of the requested output port can be
                changed, but the value of the Transmit Cell Rate field
                is beyond the range of acceptable values, a failure
                response must be returned with the Code field
                indicating: "Requested transmit cell rate out of range
                for this output port." In the failure response message
                the Transmit Cell Rate must contain the same value as
                contained in the request message that caused the
                failure. The transmit cell rate of the output port is
                not changed by the Bring Up, Take Down, or any of the
                Loopback functions. It is returned to the default
                value by the Reset Input Port function.

Newman, et. al. Informational [Page 33] RFC 2297 Ipsilon's General Switch Management March 1998

      Transmit Cell Rate
           This field is only used in request and success response
           messages with the Function field set to "Set Transmit Cell
           Rate." It is used to set the output cell rate of the output
           port. It is specified in cells/s. If the Transmit Cell Rate
           field contains the value 0xFFFFFFFF the transmit cell rate
           of the output port should be set to the highest valid
           value.

5.2. Label Range Message

 The default label range, Min VPI to Max VPI and Min VCI to Max VCI,
 is specified for each port by the Port Configuration or the All Ports
 Configuration messages.  When the protocol is initialized, before the
 transmission of any Label Range messages, the label range of each
 port will be set to the default label range. (The default label range
 is dependent upon the switch design and configuration and is not
 specified by the GSMP protocol.) The Label Range message allows the
 range of VPIs supported by a specified port, or the range of VCIs
 supported by a specified VPI on a specified port, to be changed.
 Each switch port must declare whether it supports the Label Range
 message in the Port Configuration or the All Ports Configuration
 messages.  The Label Range message is:
    Message Type = 33
 The Label Range message has the following format for the request and
 success response messages:
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                             Port                              |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      Port Session Number                      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |Q|V|x x|      Min VPI          |x x x x|       Max VPI         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |            Min VCI            |           Max VCI             |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |        Remaining VPIs         |        Remaining VCIs         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Newman, et. al. Informational [Page 34] RFC 2297 Ipsilon's General Switch Management March 1998

 Flags
      Q: Query
           If the Query flag is set in a request message, the switch
           must respond with the current range of valid VPIs, or the
           current range of valid VCIs on a specified VPI, according
           to the VPI/VCI flag. The current label range is not changed
           by a request message with the Query flag set. If the Query
           flag is zero, the message is requesting a label change
           operation.
      V: VPI/VCI
           If the VPI/VCI flag is set, the message refers to a range
           of VPIs only. The Min VCI and Max VCI fields are unused. If
           the VPI/VCI flag is zero the message refers to a range of
           VCIs on either one VPI or on a range of VPIs.
      x: Unused
 Min VPI
 Max VPI
           Specify a range of VPI values, Min VPI to Max VPI
           inclusive.  A single VPI may be specified with a Min VPI
           and a Max VPI having the same value.  In a request message,
           if the value of the Max VPI field is less than or equal to
           the value of the Min VPI field, the requested range is a
           single VPI with a value equal to the Min VPI field. Zero is
           a valid value.  In a request message, if the Query flag is
           set, and the VPI/VCI flag is zero, the Max VPI field
           specifies a single VPI and the Min VPI field is not used.
           The maximum valid value of these fields for both request
           and response messages is 0xFFF.
 Min VCI
 Max VCI
           Specify a range of VCI values, Min VCI to Max VCI
           inclusive.  A single VCI may be specified with a Min VCI
           and a Max VCI having the same value.  In a request message,
           if the value of the Max VCI field is less than or equal to
           the value of the Min VCI field, the requested range is a
           single VCI with a value equal to the Min VCI field. Zero is
           a valid value.  (However, VPI=0, VCI=0 is not available as
           a virtual channel connection as it is used as a special
           value in ATM to indicate an unassigned cell.)
 Remaining VPIs
 Remaining VCIs
           These fields are unused in the request message. In the

Newman, et. al. Informational [Page 35] RFC 2297 Ipsilon's General Switch Management March 1998

           success response message and in the failure response
           message these fields give the maximum number of remaining
           VPIs and VCIs that could be requested for allocation on the
           specified port (after completion of the requested operation
           in the case of the success response). It gives the switch
           controller an idea of how many VPIs and VCIs it could
           request. The number given is the maximum possible given the
           constraints of the switch hardware. There is no implication
           that this number of VPIs and VCIs is available to every
           switch port.
 If the Query flag and the VPI/VCI flag are set in the request
 message, the switch must reply with a success response message
 containing the current range of valid VPIs that are supported by the
 port.  The Min VPI and Max VPI fields are not used in the request
 message.
 If the Query flag is set and the VPI/VCI flag is zero in the request
 message, the switch must reply with a success response message
 containing the current range of valid VCIs that are supported by the
 VPI specified by the Max VPI field.  If the requested VPI is invalid,
 a failure response must be returned indicating: "One or more of the
 specified input VPIs is invalid." The Min VPI field is not used in
 either the request or success response messages.
 If the Query flag is zero and the VPI/VCI flag is set in the request
 message, the Min VPI and Max VPI fields specify the new range of VPIs
 to be allocated to the input port specified by the Port field.
 Whatever the range of VPIs previously allocated to this port it
 should be increased or decreased to the specified value.
 If the Query flag and the VPI/VCI flag are zero in the request
 message, the Min VCI and Max VCI fields specify the range of VCIs to
 be allocated to each of the VPIs specified by the VPI range.
 Whatever the range of VCIs previously allocated to each of the VPIs
 within the specified VPI range on this port, it should be increased
 or decreased to the specified value.  The allocated VCI range must be
 the same on each of the VPIs within the specified VPI range.
 The success response to a Label Range message requesting a change of
 label range is a copy of the request message with the Remaining VPIs
 and Remaining VCIs fields updated to the new values after the Label
 Range operation.
 If the switch is unable to satisfy a request to change the VPI range,
 it must return a failure response message with the Code field set to
 "Cannot support requested VPI range." In this failure response

Newman, et. al. Informational [Page 36] RFC 2297 Ipsilon's General Switch Management March 1998

 message the switch must use the Min VPI and Max VPI fields to suggest
 a VPI range that it would be able to satisfy.
 If the switch is unable to satisfy a request to change the VCI range
 on all VPIs within the requested VPI range, it must return a failure
 response message with the Code field set to "Cannot support requested
 VCI range on all requested VPIs." In this failure response message
 the switch must use the Min VPI, Max VPI, Min VCI, and Max VCI fields
 to suggest a VPI and VCI range that it would be able to satisfy.
 In all other failure response messages for the label range operation
 the switch must return the values of Min VPI, Max VPI, Min VCI, and
 Max VCI from the request message.
 While switches can typically support all 256 or 4096 VPIs the VCI
 range that can be supported is often more constrained. Often the Min
 VCI must be 0 or 32. Typically all VCIs within a particular VPI must
 be contiguous.  The hint in the failure response message allows the
 switch to suggest a label range that it could satisfy in view of its
 particular architecture.
 While the Label Range message is defined to specify both a range of
 VPIs and a range of VCIs within each VPI, the most likely use is to
 change either the VPI range or the range of VCIs within a single VPI.
 It is possible for a VPI to be valid but to be allocated no valid
 VCIs. Such a VPI could be used for a virtual path connection but to
 support virtual channel connections it would need to be allocated a
 range of VCIs.
 A Label Range request message may be issued regardless of the Port
 Status or the Line Status of the target switch port. If the Port
 field of the request message contains an invalid port (a port that
 does not exist or a port that has been removed from the switch) a
 failure response message must be returned with the Code field set to,
 "One or more of the specified ports does not exist."

6. State and Statistics Messages

 The state and statistics messages permit the controller to request
 the values of various hardware counters associated with the switch
 input and output ports, virtual path connections, virtual channel
 connections, and QoS Classes.  They also permit the controller to
 request the connection state of a switch input port.  The Connection
 Activity message is used to determine whether one or more specific
 virtual channel connections or virtual path connections have recently
 been carrying traffic.  The Statistics message is used to query the
 various port, connection, and QoS class traffic and error counters.

Newman, et. al. Informational [Page 37] RFC 2297 Ipsilon's General Switch Management March 1998

 The Report Connection State message is used to request an input port
 to report the connection state for a single virtual channel
 connection, a single virtual path connection, or for the entire input
 port.

6.1 Connection Activity Message

 The Connection Activity message is used to determine whether one or
 more specific virtual channel connections or virtual path connections
 have recently been carrying traffic. The Connection Activity message
 contains one or more Activity Records. Each Activity Record is used
 to request and return activity information concerning a single
 virtual channel connection or virtual path connection.  Each virtual
 channel connection is specified by its input port, input VPI, and
 input VCI. Each virtual path connection is specified by its input
 port and input VPI. These are specified in the Input Port, Input VPI,
 and Input VCI fields of each Activity Record.  Two forms of activity
 detection are supported. If the switch supports per connection
 traffic accounting, the current value of the traffic counter for each
 specified virtual channel connection or virtual path connection must
 be returned. The units of traffic counted are not specified but will
 typically be either cells or frames.  The controller must compare the
 traffic counts returned in the message with previous values for each
 of the specified connections to determine whether each connection has
 been active in the intervening period.  If the switch does not
 support per connection traffic accounting, but is capable of
 detecting per connection activity by some other unspecified means,
 the result may be indicated for each connection using the Flags
 field. The Connection Activity message is:
    Message Type = 48
 The Connection Activity request and success response messages have
 the following format:
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Number of Records       |           Reserved            |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 ~                       Activity Records                        ~
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Newman, et. al. Informational [Page 38] RFC 2297 Ipsilon's General Switch Management March 1998

 Number of Records
           Field specifies the number of Activity Records to follow.
           The number of Connection Activity records in a single
           Connection Activity message must not cause the packet
           length to exceed the maximum transmission unit defined by
           the encapsulation.
 Each Activity Record has the following format:
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                          Input Port                           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |V|C|A|x|      Input VPI        |          Input VCI            |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 +                         Traffic Count                         +
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Input Port
           Identifies the port number of the input port on which the
           connection of interest arrives in order to identify the
           connection (regardless of whether the traffic count for the
           connection is maintained on the input port or the output
           port).
 Input VPI
 Input VCI
           Fields identify the specific virtual path connection or
           virtual channel connection for which statistics are being
           requested. For a virtual path connection the Input VCI
           field is not used.
 Flags
      V: Valid Record
           In the success response message the Valid Record flag is
           used to indicate an invalid Activity Record. The flag must
           be zero if any of the fields in this Activity Record are
           invalid, if the input port specified by the Input Port
           field does not exist, or if the specified connection does
           not exist. If the Valid Record flag is zero in a success
           response message, the Counter flag, the Activity flag, and
           the VC Traffic Count field are undefined. If the Valid
           Record flag is set, the Activity Record is valid, and the
           Counter and Activity flags are valid. The Valid Record flag
           is not used in the request message.

Newman, et. al. Informational [Page 39] RFC 2297 Ipsilon's General Switch Management March 1998

      C: Counter
           In a success response message, if the Valid Record flag is
           set, the Counter flag, if zero, indicates that the value in
           the VC Traffic Count field is valid.  If set, it indicates
           that the value in the Activity flag is valid. The Counter
           flag is not used in the request message.
      A: Activity
           In a success response message, if the Valid Record and
           Counter flags are set, the Activity flag, if set, indicates
           that there has been some activity on this connection since
           the last Connection Activity message for this connection.
           If zero, it indicates that there has been no activity on
           this connection since the last Connection Activity message
           for this connection. The Activity flag is not used in the
           request message.
      x: Unused
 Traffic Count
           Field is not used in the request message.  In the success
           response message, if the switch supports per connection
           traffic counting, the Traffic Count field must be set to
           the value of a free running, connection specific, 64-bit
           traffic counter counting traffic flowing across the
           specified connection.  The value of the traffic counter is
           not modified by reading it.  If per connection traffic
           counting is supported, the switch must report the
           Connection Activity result using the traffic count rather
           than using the Activity flag.
 The format of the failure response is the same as the request message
 with the Number of Records field set to zero and no VC Activity
 records returned in the message. If the switch is incapable of
 detecting per connection activity, a failure response must be
 returned indicating, "The specified request is not implemented on
 this switch."

6.2 Statistics Messages

 The Statistics messages are used to query the various port,
 connection, and QoS class traffic and error counters.
 The Statistics request messages have the following format:

Newman, et. al. Informational [Page 40] RFC 2297 Ipsilon's General Switch Management March 1998

  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                             Port                              |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | zero  |          VPI          |              VCI              |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      QoS Class Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 VPI
 VCI
           Fields identify the specific virtual path connection or
           virtual channel connection for which statistics are being
           requested.  For a virtual path connection the Input VCI
           field is not used.  For requests that do not require a
           virtual path connection or virtual channel connection to be
           specified, the VPI and VCI fields are not used.
 QoS Class Identifier
           Field identifies the QoS class for which statistics are
           being requested. This field is only used if the QoS Class
           Establishment message defined in section 9.4 is
           implemented.
 The success response for the Statistics message has the following
 format:

Newman, et. al. Informational [Page 41] RFC 2297 Ipsilon's General Switch Management March 1998

  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                             Port                              |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | zero  |          VPI          |              VCI              |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      QoS Class Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 +                       Input Cell Count                        +
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 +                       Input Frame Count                       +
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 +                    Input Cell Discard Count                   +
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 +                   Input Frame Discard Count                   +
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 +                     Input HEC Error Count                     +
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 +                  Input Invalid VPI/VCI Count                  +
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 +                       Output Cell Count                       +
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 +                      Output Frame Count                       +
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 +                   Output Cell Discard Count                   +
 |                                                               |

Newman, et. al. Informational [Page 42] RFC 2297 Ipsilon's General Switch Management March 1998

 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 +                  Output Frame Discard Count                   +
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Port
 VPI/VCI
 QoS Class Identifier
           Fields are the same as those of the request message.
 Input Cell Count
 Output Cell Count
           Give the value of a free running 64-bit counter counting
           cells arriving at the input or departing from the output
           respectively.
 Input Frame Count
 Output Frame Count
           Give the value of a free running 64-bit counter counting
           frames (packets) arriving at the input or departing from
           the output respectively.
 Input Cell Discard Count
 Output Cell Discard Count
           Give the value of a free running 64-bit counter counting
           cells discarded due to queue overflow on an input port or
           on an output port respectively.
 Input Frame Discard Count
 Output Frame Discard Count
           Give the value of a free running 64-bit counter counting
           frames discarded due to congestion on an input port or on
           an output port respectively.
 HEC Error Count
           Gives the value of a free running 64-bit counter counting
           cells discarded due to header checksum errors on arrival at
           an input port.
 Invalid VPI/VCI Count
           Gives the value of a free running 64-bit counter counting
           cells discarded because their VPI/VCI is invalid on arrival
           at an input port. For a virtual channel connection an
           incoming VPI/VCI is invalid if no connection is currently
           established having that value of VPI/VCI. For a virtual
           path connection an incoming VPI is invalid if no connection
           is currently established having that value of VPI.

Newman, et. al. Informational [Page 43] RFC 2297 Ipsilon's General Switch Management March 1998

6.2.1 Port Statistics Message

 The Port Statistics message requests the statistics for the switch
 port specified in the Port field. The contents of the VPI/VCI and the
 QoS Class Identifier fields in the Port Statistics request message
 are ignored. All of the count fields in the success response message
 refer to per-port counts regardless of the connection or QoS class to
 which the cells belong.  Any of the count fields in the success
 response message not supported by the port must be set to zero. The
 Port Statistics message is:
    Message Type = 49

6.2.2 Connection Statistics Message

 The Connection Statistics message requests the statistics for the
 virtual channel connection specified in the VPI/VCI field, or the
 virtual path connection specified in the VPI field, that arrives on
 the switch input port specified in the Port field, regardless of the
 QoS class to which the cells belong. All of the count fields in the
 success response message refer only to the specified connection.  The
 HEC Error Count and Invalid VPI/VCI Count fields are not connection
 specific and must be set to zero. Any of the other count fields not
 supported on a per connection basis must be set to zero in the
 success response message. The Connection Statistics message is:
    Message Type = 50

6.2.3 QoS Class Statistics Message

 The QoS Class Statistics message requests the statistics for the QoS
 class specified by the QoS Class Identifier field that arrives on the
 switch input port specified in the Port field, regardless of the
 connection to which the cells belong. The QoS Statistics message is
 only used if the QoS Class Establishment message defined in section
 9.4 is implemented.  The contents of the VPI/VCI fields in the QoS
 Class Statistics request message are ignored. All of the count fields
 in the success response message refer only to the specified QoS
 class.  The HEC Error Count and Invalid VPI/VCI Count fields are not
 specific to a QoS class and must be set to zero. Any of the other
 count fields not supported on a per QoS class basis must be set to
 zero in the success response message. The QoS Class Statistics
 message is:
    Message Type = 51

Newman, et. al. Informational [Page 44] RFC 2297 Ipsilon's General Switch Management March 1998

6.3 Report Connection State Message

 The Report Connection State message is used to request an input port
 to report the connection state for a single virtual channel
 connection, a single virtual path connection, or for the entire input
 port. The Report Connection State message is:
    Message Type = 52
 The Report Connection State request message has the following format:
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                          Input Port                           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |A|V|x x|       Input VPI       |          Input VCI            |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Input Port
           Identifies the port number of the input port for which the
           connection state is being requested.
 Flags
      A: All Connections
           If the All Connections flag is set, the message requests
           the connection state for all virtual path connections and
           virtual channel connections that arrive at the input port
           specified by the Input Port field. In this case the Input
           VPI and Input VCI fields and the VPI/VCI flag are unused.
      V: VPI/VCI
           If the All Connections flag is zero and the VPI/VCI flag is
           set, the message requests the connection state for the
           virtual path connection that arrives at the input port
           specified by the Input Port and Input VPI fields.  If the
           specified Input VPI identifies a virtual path connection
           (i.e. a single switched virtual path) the state for that
           connection is requested.  If the specified Input VPI
           identifies a virtual path containing virtual channel
           connections, the message requests the connection state for
           all virtual channel connections that belong to the
           specified virtual path. The Input VCI field is not used.

Newman, et. al. Informational [Page 45] RFC 2297 Ipsilon's General Switch Management March 1998

           If the All Connections flag is zero and the VPI/VCI flag is
           also zero, the message requests the connection state for
           the virtual channel connection that arrives at the input
           port specified by the Port, Input VPI and Input VCI fields.
           x: Unused.
 Input VPI
 Input VCI
           Fields identify the specific virtual path connection, the
           specific virtual path, or the specific virtual channel
           connection for which connection state is being requested.
           For a virtual path connection (switched as a single virtual
           path connection) or a virtual path (switched as one or more
           virtual channel connections within the virtual path) the
           Input VCI field is not used.  For requests that do not
           require a virtual path connection or virtual channel
           connection to be specified, the Input VPI and Input VCI
           fields are not used.
 The Report Connection State success response message has the
 following format:
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                          Input Port                           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                       Sequence Number                         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 ~                       Connection Records                      ~
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Input Port
           Is the same as the Input Port field in the request message.
           It identifies the port number of the input port for which
           the connection state is being reported.
 Sequence Number
           In the case that the requested connection state cannot be
           reported in a single success response message, each
           successive success response message in reply to the same

Newman, et. al. Informational [Page 46] RFC 2297 Ipsilon's General Switch Management March 1998

           request message must increment the Sequence Number. The
           Sequence Number of the first success response message, in
           response to a new request message, must be zero.
 Connection Records
           Each success response message must contain one or more
           Connection Records. Each Connection Record specifies a
           single point-to-point or point-to-multipoint virtual path
           connection or virtual channel connection. The number of
           Connection Records in a single Report Connection State
           success response must not cause the packet length to exceed
           the maximum transmission unit defined by the encapsulation.
           If the requested connection state cannot be reported in a
           single success response message, multiple success response
           messages must be sent. All success response messages that
           are sent in response to the same request message must have
           the same Input Port and Transaction Identifier fields as
           the request message. A single Connection Record must not be
           split across multiple success response messages. The More
           flag of the last Connection Record in a success response
           message indicates whether the response to the request has
           been completed or whether one or more further success
           response messages should be expected in response to the
           same request message.
 Each Connection Record has the following format:
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |A|V|P|M|       Input VPI       |          Input VCI            |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 ~                      Output Branch Records                    ~
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Flags
      A: All Connections
      V: VPI/VCI
           For the first Connection Record in each success response
           message the All Connections and the VPI/VCI flags must be
           the same as those of the request message. For successive
           Connection Records in the same success response message
           these flags are not used.
      P: VPC
           The VPC flag, if set, indicates that the Connection Record
           refers to a virtual path connection.  If zero, it indicates

Newman, et. al. Informational [Page 47] RFC 2297 Ipsilon's General Switch Management March 1998

           that the Connection Record refers to a virtual channel
           connection.
      M: More
           If the More flag is set, it indicates that another
           Connection Record, in response to the same request message,
           will follow either in the same success response message or
           in a successive success response message. If the More flag
           is zero it indicates that this is the last Connection
           record in this success response message and that no further
           success response messages will be sent in response to the
           current request message. It indicates that the response to
           the request message is now complete.
 Input VPI
 Input VCI
           The input VPI and VCI of the connection specified in this
           Connection Record. If this Connection Record specifies a
           virtual path connection (the VPC flag is set) the Input VCI
           field is unused.
 Output Branch Records
           Each Connection Record must contain one or more Output
           Branch Records. Each Output Branch Record specifies a
           single output branch belonging to the connection identified
           by the Input VPI and Input VCI fields of the Connection
           Record. A point-to-point connection will require only a
           single Output Branch Record. A point-to-multipoint
           connection will require multiple Output Branch Records. The
           last Output Branch Record of each Connection Record is
           indicated by the Last Branch flag of the Output Branch
           Record. If a point-to-multipoint connection has more output
           branches than can fit in a single Connection Record
           contained within a single success response message, that
           connection may be reported using multiple Connection
           Records in multiple success response messages.
 Each Output Branch Record has the following format:
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                          Output Port                          |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |L|x x x|       Output VPI      |          Output VCI           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Output Port
           The output port of the switch to which this output branch
           is routed.

Newman, et. al. Informational [Page 48] RFC 2297 Ipsilon's General Switch Management March 1998

 Flags
      L: Last Branch
           The Last Branch flag, if set, indicates that this is the
           last Output Branch Record of this Connection Record. If
           zero, it indicates that one or more further Output Branch
           Records are to follow. If this is the last Output Branch
           Record in the message and the Last Branch flag is zero,
           further output branches belonging to the same connection
           will be given in another Connection Record. This Connection
           Record will be the first Connection Record in the next
           success response message. This Connection Record must have
           the same Input VPI and Input VCI values as the current
           Connection Record.
           x: Unused.
 Output VPI
 Output VCI
           The output VPI and VCI of the output branch specified in
           this Output Branch Record.  If this Output Branch Record is
           part of a Connection Record that specifies a virtual path
           connection (the VPC flag is set) the Output VCI field is
           unused.
 A Report Connection State request message may be issued regardless of
 the Port Status or the Line Status of the target switch port.
 If the Input Port of the request message is valid, and the All
 Connections flag is set, but there are no connections established on
 that port, a failure response message must be returned with the code
 field set to, "Failure specific to the particular message type." For
 the Report Connection State message, this failure code indicates that
 no connections matching the request message were found.  This failure
 message should also be returned if the Input Port of the request
 message is valid, the All Connections flag is zero, and no
 connections are found on that port matching the specified virtual
 path connection, virtual path, or virtual channel connection.

7. Configuration Messages

 The configuration messages permit the controller to discover the
 capabilities of the switch. Three configuration request messages have
 been defined: Switch, Port, and All Ports.
 All configuration request messages have the following format:

Newman, et. al. Informational [Page 49] RFC 2297 Ipsilon's General Switch Management March 1998

  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                             Port                              |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

7.1 Switch Configuration Message

 The Switch Configuration message requests the global (non port-
 specific) configuration for the switch. The Switch Configuration
 message is:
    Message Type = 64
 The Port field is not used in the request message.
 The Switch Configuration success response message has the following
 format:
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Firmware Version Number    |          Window Size          |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |          Switch Type          |                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
 |                          Switch Name                          |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Firmware Version Number
           The version number of the switch control firmware
           installed.
 Window Size
           The maximum number of unacknowledged request messages that
           may be transmitted by the controller without the
           possibility of loss.  This field is used to prevent request
           messages being lost in the switch because of overflow in
           the receive buffer. The field is a hint to the controller.
           If desired, the controller may experiment with higher and

Newman, et. al. Informational [Page 50] RFC 2297 Ipsilon's General Switch Management March 1998

           lower window sizes to determine heuristically the best
           window size.
 Switch Type
           A 16-bit field allocated by the manufacturer of the switch.
           (For these purposes the manufacturer of the switch is
           assumed to be the organization identified by the OUI in the
           Switch Name field.) The Switch Type identifies the product.
           When the Switch Type is combined with the OUI from the
           Switch Name the product is uniquely identified. Network
           Management may use this identification to obtain product
           related information from a database.
 Switch Name
           A 48-bit quantity that is unique within the operational
           context of the device. A 48-bit IEEE 802 MAC address, if
           available, may be used as the Switch Name. The most
           significant 24 bits of the Switch Name must be an
           Organizationally Unique Identifier (OUI) that identifies
           the manufacturer of the switch.

7.2 Port Configuration Message

 The Port Configuration message requests the switch for the
 configuration information of a single switch port. The Port field in
 the request message specifies the port for which the configuration is
 requested.  The Port Configuration message is:
    Message Type = 65.
 The Port Configuration success response message has the following
 format:

Newman, et. al. Informational [Page 51] RFC 2297 Ipsilon's General Switch Management March 1998

  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                             Port                              |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                       Port Session Number                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |V|M|L|R|      Min VPI          |Q|x x x|       Max VPI         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |            Min VCI            |           Max VCI             |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                       Receive Cell Rate                       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      Transmit Cell Rate                       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |  Port Status  |   Port Type   |  Line Status  |  Priorities   |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Physical Slot Number      |     Physical Port Number      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Port
           The switch port to which the configuration information
           refers. Configuration information relating to both the
           input and the output sides of the switch port is given.
           Port numbers are 32 bits wide and allocated by the switch.
           The switch may choose to structure the 32 bits into
           subfields that have meaning to the physical structure of
           the switch hardware (e.g.  physical slot and port). This
           structure may be indicated in the Physical Slot Number and
           Physical Port Number fields.
 Flags
      V: VP Switching
           The VP Switching flag, if set, indicates that this input
           port is capable of supporting virtual path switching. Else,
           if zero, it indicates that this input port is only capable
           of virtual channel switching.
      M: Multicast Labels
           The Multicast Labels flag, if set, indicates that this
           output port is capable of labelling each output branch of a
           point-to-multipoint tree with a different label. If zero,
           it indicates that this output port is not able to label

Newman, et. al. Informational [Page 52] RFC 2297 Ipsilon's General Switch Management March 1998

           each output branch of a point-to-multipoint tree with a
           different label.
      L: Logical Multicast
           The Logical Multicast flag, if set, indicates that this
           output port is capable of supporting more than a single
           branch from any point-to-multipoint connection.  This
           capability is often referred to as logical multicast.  If
           zero, it indicates that this output port can only support a
           single output branch from each point-to-multipoint
           connection.
      R: Label Range
           The Label Range flag, if set, indicates that this switch
           port is capable of reallocating its VPI label range or its
           VCI label range and therefore accepts the Label Range
           message. Else, if zero, it indicates that this port does
           not accept Label Range messages.
      Q: QoS
           The QoS flag, if set, indicates that this switch port is
           capable of handling the Quality of Service messages defined
           in section 9 of this specification.  Else, if zero, it
           indicates that this port does not accept the Quality of
           Service messages.
      x: Unused
 Min VPI
           The default minimum value of dynamically assigned incoming
           VPI that the connection table on the input port supports
           and that may be controlled by GSMP. This value is not
           changed as a result of the Label Range message.
 Max VPI
           The default maximum value of dynamically assigned incoming
           VPI that the connection table on the input port supports
           and that may be controlled by GSMP.  This value is not
           changed as a result of the Label Range message.
           At power-on, after a hardware reset, and after the Reset
           Input Port function of the Port Management message, the
           input port must handle all values of VPI within the range
           Min VPI to Max VPI inclusive and GSMP must be able to
           control all values within this range.  It should be noted
           that the range Min VPI to Max VPI refers only to the
           incoming VPI range that can be supported by the associated
           port. No restriction is placed on the values of outgoing

Newman, et. al. Informational [Page 53] RFC 2297 Ipsilon's General Switch Management March 1998

           VPIs that may be written into the cell header. If the
           switch does not support virtual paths it is acceptable for
           both Min VPI and Max VPI to specify the same value, most
           likely zero.
           Use of the Label Range message allows the range of VPIs
           supported by the port to be changed. However, the Min VPI
           and Max VPI fields in the Port Configuration and All Ports
           Configuration messages always report the same default
           values regardless of the operation of the Label Range
           message.
 Min VCI
           The default minimum value of dynamically assigned incoming
           VCI that the connection table on the input port can support
           and may be controlled by GSMP. This value is not changed as
           a result of the Label Range message.
 Max VCI
           The default maximum value of dynamically assigned incoming
           VCI that the connection table on the input port can support
           and may be controlled by GSMP. This value is not changed as
           a result of the Label Range message.
           At power-on, after a hardware reset, and after the Reset
           Input Port function of the Port Management message, the
           input port must handle all values of VCI within the range
           Min VCI to Max VCI inclusive, for each of the virtual paths
           in the range Min VPI to Max VPI inclusive, and GSMP must be
           able to control all values within this range.  It should be
           noted that the range Min VCI to Max VCI refers only to the
           incoming VCI range that can be supported by the associated
           port on each of the virtual paths in the range Min VPI to
           Max VPI. No restriction is placed on the values of outgoing
           VCIs that may be written into the cell header.
           Use of the Label Range message allows the range of VCIs to
           be changed on each VPI supported by the port.  However, the
           Min VCI and Max VCI fields in the Port Configuration and
           All Ports Configuration messages always report the same
           default values regardless of the operation of the Label
           Range message.
           For a port over which the GSMP protocol is operating, the
           VCI of the GSMP control channel may or may not be reported
           as lying within the range Min VCI to Max VCI.  A switch
           should honor a connection request message that specifies

Newman, et. al. Informational [Page 54] RFC 2297 Ipsilon's General Switch Management March 1998

           the VCI value of the GSMP control channel even if it lies
           outside the range Min VCI to Max VCI.
 Receive Cell Rate
           The maximum rate of cells that may arrive at the input port
           in cells/s.
 Transmit Cell Rate
           The maximum rate of cells that may depart from the output
           port in cells/s. (The transmit cell rate of the output port
           may be changed by the Set Transmit Cell Rate function of
           the Port Management message.)
 Port Status
           Gives the administrative state of the port. The defined
           values of the Port Status field are:
           Available:
                Port Status = 1. The port is available to both send
                and receive cells. When a port changes to the
                Available state from any other administrative state,
                all dynamically assigned virtual connections must be
                cleared and a new Port Session Number must be
                generated.
           Unavailable:
                Port Status = 2. The port has intentionally been taken
                out of service. No cells will be transmitted from this
                port.  No cells will be received by this port.
           Internal Loopback:
                Port Status = 3. The port has intentionally been taken
                out of service and is in internal loopback: cells
                arriving at the output port from the switch fabric are
                looped through to the input port to return to the
                switch fabric. All of the ATM functions of the input
                port above the physical layer, e.g. header
                translation, are performed upon the looped back cells.
           External Loopback:
                Port Status = 4. The port has intentionally been taken
                out of service and is in external loopback: cells
                arriving at the input port from the external
                communications link are immediately looped back to the
                communications link at the physical layer without
                entering the input port. None of the ATM functions of
                the input port above the physical layer are performed
                upon the looped back cells.

Newman, et. al. Informational [Page 55] RFC 2297 Ipsilon's General Switch Management March 1998

           Bothway Loopback:
                Port Status = 5. The port has intentionally been taken
                out of service and is in both internal and external
                loopback.
           The Port Status of the port over which the GSMP session
           controlling the switch is running, must be declared
           Available. The controller will ignore any other Port status
           for this port. The Port Status of switch ports after
           power-on initialization is not defined by GSMP.
 Port Type
           The type of physical transmission interface for this port.
           The values for this field are defined by the atmIfType
           object specified in the Ipsilon IP Switch MIB [IpsilonMIB].
 Line Status
           The status of the physical transmission medium connected to
           the port. The defined values of the Line Status field are:
           Up:
                Line Status = 1. The line is able to both send and
                receive cells.  When the Line Status changes to Up
                from either the Down or Test states, a new Port
                Session Number must be generated.
           Down:
                Line Status = 2. The line is unable either to send or
                receive cells or both.
           Test:
                Line Status = 3. The port or line is in a test mode,
                for example, power-on test.
 Priorities
           The number of different priority levels that this output
           port can assign to virtual connections.  Zero is invalid in
           this field. If an output port is able to support "Q"
           priorities, the highest priority is numbered zero and the
           lowest priority is numbered "Q-1". The ability to offer
           different qualities of service to different connections
           based upon their priority is assumed to be a property of
           the output port of the switch. It may be assumed that for
           connections that share the same output port, an ATM cell on
           a connection with a higher priority is much more likely to
           exit the switch before an ATM cell on a connection with a
           lower priority if they are both in the switch at the same
           time.

Newman, et. al. Informational [Page 56] RFC 2297 Ipsilon's General Switch Management March 1998

 Physical Slot Number
           The physical location of the slot in which the port is
           located. It is an unsigned 16-bit integer that can take any
           value except 0xFFFF. The value 0xFFFF is used to indicate
           "unknown." The Physical Slot Number is not used by the GSMP
           protocol. It is provided to assist network management in
           functions such as logging, port naming, and graphical
           representation.
 Physical Port Number
           The physical location of the port within the slot in which
           the port is located. It is an unsigned 16-bit integer that
           can take any value except 0xFFFF. The value 0xFFFF is used
           to indicate "unknown." The Physical Port Number is not used
           by the GSMP protocol. It is provided to assist network
           management in functions such as logging, port naming, and
           graphical representation.
           There must be a one to one mapping between Port Number and
           the Physical Slot Number and Physical Port Number
           combination. Two different Port Numbers must not yield the
           same Physical Slot Number and Physical Port Number
           combination. The same Port Number must yield the same
           Physical Slot Number and Physical Port Number within a
           single GSMP session.  If both Physical Slot Number and
           Physical Port Number indicate "unknown" the physical
           location of switch ports may be discovered by looking up
           the product identity in a database to reveal the physical
           interpretation of the 32-bit Port Number.

7.3 All Ports Configuration Message

 The All Ports Configuration message requests the switch for the
 configuration information of all of its ports. The All Ports
 Configuration message is:
    Message Type = 66
 The Port field is not used in the request message.
 The All Ports Configuration success response message has the
 following format:

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  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Number of Records       |      Port Record Length       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 ~                          Port Records                         ~
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Number of Records
           Field gives the total number of Port Records to be returned
           in response to the All Ports Configuration request message.
           The number of port records in a single All Ports
           Configuration success response must not cause the packet
           length to exceed the maximum transmission unit defined by
           the encapsulation. If a switch has more ports than can be
           sent in a single success response message it must send
           multiple success response messages. All success response
           messages that are sent in response to the same request
           message must have the same Transaction Identifier as the
           request message and the same value in the Number of Records
           field.  All success response messages that are sent in
           response to the same request message, except for the last
           message, must have the result field set to "More." The last
           message, or a single success response message, must have
           the result field set to "Success." All Port records within
           a success response message must be complete, i.e. a single
           Port record must not be split across multiple success
           response messages.
 Port Record Length
           Field gives the length of each port record in bytes. This
           is currently 32 but the Port Record Length field allows for
           the future definition of further fields at the end of the
           port record while preserving compatibility with earlier
           versions of the protocol.
 Port Records
           Follow in the remainder of the message. Each port record
           has the following format:

Newman, et. al. Informational [Page 58] RFC 2297 Ipsilon's General Switch Management March 1998

  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                             Port                              |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                       Port Session Number                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |V|M|L|R|      Min VPI          |Q|x x x|       Max VPI         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |            Min VCI            |           Max VCI             |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                       Receive Cell Rate                       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      Transmit Cell Rate                       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |  Port Status  |   Port Type   |  Line Status  |  Priorities   |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Physical Slot Number      |     Physical Port Number      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 The definition of the fields in the Port Record is exactly the same
 as that of the Port Configuration message.

8. Event Messages

 Event messages allow the switch to inform the controller of certain
 asynchronous events. Event messages are not acknowledged. The Result
 field and the Code field in the message header are not used and
 should be set to zero. Event messages are not sent during
 initialization. Event messages have the following format:
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                             Port                              |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      Port Session Number                      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                     Event Sequence Number                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | zero  |          VPI          |              VCI              |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Newman, et. al. Informational [Page 59] RFC 2297 Ipsilon's General Switch Management March 1998

 Event Sequence Number
           The current value of the Event Sequence Number for the
           specified port. The Event Sequence Number is set to zero
           when the port is initialized. It is incremented by one each
           time the port detects an asynchronous event that the switch
           would normally report via an Event message. The Event
           Sequence Number must be incremented each time an event
           occurs even if the switch is prevented from sending an
           Event message due to the action of the flow control.
 VPI/VCI
           Field gives the VPI/VCI to which the event message refers.
           If this field is not required by the event message it is
           set to zero.
 Each switch port must maintain an Event Sequence Number and a set of
 Event Flags, one Event Flag for each type of Event message.  When a
 switch port sends an Event message it must set the Event Flag on that
 port corresponding to the type of the event. The port is not
 permitted to send another Event message of the same type until the
 Event Flag has been reset. Event Flags are reset by the "Reset Event
 Flags" function of the Port Management message. This is a simple flow
 control preventing the switch from flooding the controller with event
 messages. The Event Sequence Number of the port must be incremented
 every time an event is detected on that port even if the port is
 prevented from reporting the event due to the action of the flow
 control. This allows the controller to detect that it has not been
 informed of some events that have occurred on the port due to the
 action of the flow control.

8.1 Port Up Message

 The Port Up message informs the controller that the Line Status of a
 port has changed from either the Down or Test state to the Up state.
 When the Line Status of a switch port changes to the Up state from
 either the Down or Test state a new Port Session Number must be
 generated, preferably using some form of random number. The new Port
 Session Number is given in the Port Session Number field. The VPI/VCI
 field is not used and is set to zero.  The Port Up message is:
    Message Type = 80

8.2 Port Down Message

 The Port Down message informs the controller that the Line Status of
 a port has changed from the Up state to the Down state. This message
 will be sent to report link failure if the switch is capable of
 detecting link failure. The port session number that was valid before

Newman, et. al. Informational [Page 60] RFC 2297 Ipsilon's General Switch Management March 1998

 the port went down is reported in the Port Session Number field. The
 VPI/VCI field is not used and is set to zero. The Port Down message
 is:
    Message Type = 81

8.3 Invalid VPI/VCI Message

 The Invalid VPI/VCI message is sent to inform the controller that one
 or more cells have arrived at an input port with a VPI/VCI that is
 currently not allocated to an assigned connection. The input port is
 indicated in the Port field, and the VPI/VCI in the VPI/VCI field.
 The Invalid VPI/VCI message is:
    Message Type = 82

8.4 New Port Message

 The New Port message informs the controller that a new port has been
 added to the switch. The port number of the new port is given in the
 Port field. A new Port Session Number must be assigned, preferably
 using some form of random number.  The new Port Session Number is
 given in the Port Session Number field.  The state of the new port is
 undefined so the VPI/VCI field is not used and is set to zero.  The
 New Port message is:
    Message Type = 83

8.5 Dead Port Message

 The Dead Port message informs the controller that a port has been
 removed from the switch. The port number of the port is given in the
 Port field. The Port Session Number that was valid before the port
 was removed is reported in the Port Session Number field.  The
 VPI/VCI fields are not used and are set to zero. The Dead Port
 message is:
    Message Type = 84

9. Quality of Service Messages

 The GSMP Quality of Service (QoS) messages allow a controller to
 group virtual path connections and virtual channel connections into
 QoS classes, and to allocate QoS resources to both QoS classes and to
 individual connections. At initialization, the switch describes its
 QoS capabilities to the controller, in terms of the abstract switch
 model, using the QoS Configuration message. The controller issues

Newman, et. al. Informational [Page 61] RFC 2297 Ipsilon's General Switch Management March 1998

 Scheduler Establishment messages to configure the scheduler on each
 switch output port. It also issues QoS Class Establishment messages
 to configure QoS classes. Connections may be added to, or deleted
 from, a QoS class using the QoS Connection Management message. QoS
 resources may also be assigned to individual connections using the
 QoS Connection Management message. Connections that only require the
 scheduler may use the simple connection management messages defined
 in Section 3, "Connection Management Messages."

9.1 Abstract Switch Model

 The abstract switch model, fig. 1, is the means by which a switch can
 describe its fundamental QoS capabilities to a controller. It
 consists of four main functions: a policer, a classifier, a
 regulator, and a scheduler.  The classifier groups multiple
 connections (VPCs or VCCs) together into a QoS class such that QoS
 resources may be shared by the QoS class as a whole. Within a QoS
 class there is no differentiation between members of the class in
 terms of QoS resources received. However, the ordering of cells
 within each constituent VPC or VCC must be preserved on exit from the
 switch. Connections are not required to be aggregated into a QoS
 class with other connections; they may be allocated individual QoS
 resources.

Newman, et. al. Informational [Page 62] RFC 2297 Ipsilon's General Switch Management March 1998

 VPC/VCCs  Policer  Classifier   Regulator       Scheduler
           +--+     +----+                       +--------+
  -------->|  |---->|    |                       |        |
           +--+     |    |                       |        |
                    |    |                       |        |
           +--+     |    |       +----+          |        |
  -------->|  |---->|    |       |    |--------->|        |
           +--+     |    |       |    |conforming|        |
                    |    |------>|    |          |        |
           +--+     |    |  QoS  |    |          |        |
  -------->|  |---->|    | Class |    |--------->|        |
           +--+     |    |       +----+  excess  |        |
                    |    |                       |        |
           +--+     |    |                       |        |
  -------->|  |---->|    |                       |        |
           +--+     +----+                       |        |
                                                 |        |
                                                 |        |   Output
                                                 |        |    Port
                                                 |        |---------->
                                                 |        |
                                                 |        |
           +--+     +----+                       |        |
  -------->|  |---->|    |                       |        |
           +--+     |    |                       |        |
                    |    |                       |        |
           +--+     |    |       +----+          |        |
  -------->|  |---->|    |       |    |--------->|        |
           +--+     |    |       |    |conforming|        |
                    |    |------>|    |          |        |
           +--+     |    |  QoS  |    |          |        |
  -------->|  |---->|    | Class |    |--------->|        |
           +--+     |    |       +----+  excess  |        |
                    |    |                       |        |
           +--+     |    |                       |        |
  -------->|  |---->|    |                       |        |
           +--+     +----+                       |        |
                                                 +--------+
                     Fig. 1: Abstract Switch Model
 The policer is a single input, single output device that can discard
 or tag cells.  A policer may be applied to police each individual
 connection.  A policer may also be applied to police the aggregate
 traffic of a QoS class.  The policer is  used to enforce an upper
 bound on the traffic on a connection or on a QoS class.

Newman, et. al. Informational [Page 63] RFC 2297 Ipsilon's General Switch Management March 1998

 The regulator follows the policer and classifier. It offers either a
 policing function or a shaping function. The policing function
 evaluates cells as conforming to the rate specified by the regulator
 parameters or as being in excess of that rate. One of three actions
 can be specified to be taken for each cell as a result of this
 evaluation: tagging, discard or differentiated scheduling. Tagging
 sets the CLP bit of cells deemed to be in excess of the rate defined
 by the regulator parameters.  The discard function discards excess
 cells. The differentiated scheduling function allows conforming cells
 and excess cells to be scheduled for service at different points in
 the scheduler. This would allow conforming cells, for example, to
 receive service with a QoS guarantee, whereas excess cells receive
 best-effort service.  The implementation of differentiated
 scheduling, however, is complicated by the requirement not to reorder
 cells within each connection.
 The shaping function of the regulator paces cells out, on each QoS
 class or individual connection, at the rate specified by the
 regulator parameters. No jitter requirement may be specified, nor is
 any specific guarantee of jitter given. If traffic arrives on any QoS
 class or individual connection at a greater rate than the output rate
 specified, that traffic will be delayed. If the delayed traffic for
 any QoS class or individual connection exceeds a bound, discard will
 occur.  Differentiated scheduling is supported by the shaper but its
 application to shaping is somewhat different than its application to
 policing. Conforming traffic is that traffic which leaves the shaper
 as a result of the shaping process.  The conforming pointer specifies
 the point in the scheduler structure where such traffic is scheduled
 for output. (This is typically the highest priority of the scheduler
 but the GSMP specification permits other priorities to be specified.)
 If an excess pointer is also enabled for a particular QoS class or
 individual connection, traffic in excess of the rate specified by the
 shaper may also be transmitted.  The position of the excess pointer
 in the scheduler structure determines the undefined amount of
 additional traffic that will be supported. The excess traffic may be
 tagged if required, if tagging is supported. The excess pointer will
 receive the same share of bandwidth that a best-effort class or
 connection would receive at the same location in the scheduler
 structure.
 The location of the classifier and regulator functions in the switch
 is important. If the classifier is located on an input port, only
 virtual connections that arrive at that input port may be aggregated
 into a QoS class. If the classifier is centralized, or located on an
 output port, virtual connections that arrive at any input port may be
 aggregated into the same QoS class. If the regulator is located on an
 output port all virtual connections within a QoS class passing
 through that regulator must exit the switch at that output port.

Newman, et. al. Informational [Page 64] RFC 2297 Ipsilon's General Switch Management March 1998

 However, if the regulator is centralized, or located on an input
 port, virtual connections that are part of the same QoS class may be
 switched to different output ports.  Each switch port must specify
 the location of its classifier and regulator functions.
 The scheduler is located on the output port, fig. 2. It distributes
 the bandwidth of the output link between the QoS classes and
 individual connections.  It is a two-level scheduler: a priority
 scheduler at one level and a FIFO or a weighted scheduler at the
 other.  Up to 255 strict priority levels may be supported. Traffic in
 any specific priority level may only be transmitted if no traffic is
 queued for transmission in any higher priority level. Within each
 priority level a weighted scheduler may be defined. Each leaf of the
 scheduler tree is connected to a waiting room. The waiting room has
 two functions. When it receives service from the scheduler, it must
 select a QoS class or individual connection for transmission. When it
 is notified of traffic arrival on a QoS class or connection, it must
 decide whether there is enough room left in the waiting room to
 accept the traffic, else that traffic must be discarded. The waiting
 room has a size parameter indicating how much traffic may be
 accepted.  Other queueing parameters may be attached to the waiting
 room. Multiple conforming and excess pointers from the regulators may
 point to each waiting room. Within a waiting room, the scheduling of
 multiple connections sharing that waiting room may support weighted
 sharing between the connections.

Newman, et. al. Informational [Page 65] RFC 2297 Ipsilon's General Switch Management March 1998

      From      Waiting        FIFO/Weighted        Priority
    Regulator     Room           Scheduler          Scheduler
                         Net       +---+
                +------+ Weight    |   |
     ---------->|      |-%-------->| 0 |------\
                +------+           |   |       \
                                   +---+        \
     ---------->+------+                        |
                |      |-%--\      +---+        |
     ---------->+------+     \---->|   |        |
                                   | 1 |---\    |
                +------+     /---->|   |    \   \
     ---------->|      |-%--/      +---+     \   \    +---+
                +------+                      \   \-->|   |
                                               \----->|   |--------->
     ---------->+------+                          /-->|   |  Output
     ---------->|      |-%-\                     /    +---+   Port
     ---------->+------+    \                   /
                             \     +---+       /
                +------+      \--->|   |      /
     ---------->|      |-%-------->| 2 |-----/
                +------+      /--->|   |
                             /     +---+
                +------+    /
     ---------->|      |-%-/
                +------+
                         Fig. 2: The Scheduler

9.2 QoS Configuration Message

 The QoS Configuration message permits the controller to discover the
 QoS capabilities of each switch port in terms of the abstract switch
 model. The QoS Configuration message is:
    Message Type = 96
 The QoS Configuration request message has the following format:

Newman, et. al. Informational [Page 66] RFC 2297 Ipsilon's General Switch Management March 1998

  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                             Port                              |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 The QoS Configuration success response message has the following
 format:
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                             Port                              |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                       Port Session Number                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |        Scheduler Flags        |       Regulator Flags         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |      Excess Capabilities      |            Reserved           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |  Hi Sharing   |  Lo Sharing   |          Max Classes          |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                          Default Size                         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                   Default Discard Threshold                   |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                          Max Buffer                           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                        Max Shaper Buffer                      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                        Scaling Factor                         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Port
           The switch port to which the QoS configuration information
           refers. QoS configuration information relating to both the
           input and the output sides of the switch port is given.

Newman, et. al. Informational [Page 67] RFC 2297 Ipsilon's General Switch Management March 1998

 Scheduler Flags
       0                   1
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |W|Q|S|G|D|F|M|B|I|x x x x x x x|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      W: Weighted Connections
           Bit 0 of the Scheduler Flags field, if set, indicates that
           a weighted service algorithm (such as weighted round-robin)
           is available for allocation of service to individual
           connections within at least some waiting rooms. It means
           that a Connection Weight parameter can be attached to a QoS
           Connection Management message. Not all waiting rooms at all
           priority levels may be able to support this function.
           Whether a particular waiting room can support this function
           will be discovered when a QoS Connection Management message
           is issued.
      Q: Weighted QoS Classes
           Bit 1 of the Scheduler Flags field, if set, indicates that
           a weighted service algorithm (such as weighted round-robin)
           is available for allocation of service to QoS classes
           within at least some waiting rooms.  It means that a QoS
           Class Weight parameter can be attached to a QoS Class
           Establishment message.  Not all waiting rooms at all
           priority levels may be able to support this function.
           Whether a particular waiting room can support this function
           will be discovered when a QoS Class Establishment message
           is issued.
      S: Shared Waiting Room
           Bit 2 of the Scheduler Flags field, if set, indicates that
           multiple QoS classes and multiple connections may be
           scheduled within a single waiting room. This is expected to
           be the normal case. If Bit 2 of the Scheduler Flags field
           is zero, it indicates that only a single QoS class or a
           single connection may be directed to any single waiting
           room.
      G: Global Max Classes
           Bit 3 of the Scheduler Flags field, if set, indicates that
           the Max Classes field gives the maximum number of QoS
           classes that may be supported by the entire switch. If
           zero, it indicates that the Max Classes field gives the
           maximum number of QoS classes that may be supported by this
           switch port.

Newman, et. al. Informational [Page 68] RFC 2297 Ipsilon's General Switch Management March 1998

      D: Packet Discard
           Bit 4 of the Scheduler Flags field, if set, indicates that
           the scheduler on this output port is capable of packet
           discard. Packet discard indicates a discard algorithm that
           is aware of AAL-5 packet boundaries and attempts to discard
           whole packets. No specific algorithm is indicated though
           Early Packet Discard (EPD) is likely to be the most common.
           Other algorithms such as "push from front" schemes, dynamic
           threshold, or Random Early Detection (RED) are also
           examples of possible packet discard algorithms. The only
           parameters available to the packet discard algorithm, via
           GSMP, are the Size and Discard Threshold of the waiting
           room.
      F: Frame-Based Scheduling
           Bit 5 of the Scheduler Flags field, if set, indicates that
           the scheduler on this output port is capable of frame-based
           scheduling. In frame-based scheduling, a connection is only
           scheduled for transmission when a complete AAL-5 packet is
           available.  When a connection is scheduled for
           transmission, all cells belonging to one or more complete
           packets from that connection will be transmitted without
           being interleaved with any other cells on that output port
           (regardless of their priority).  Frame-based scheduling is
           a property of the waiting room and is requested in the
           Scheduler Establishment message.  A QoS class may be routed
           through a waiting room configured with frame-based
           scheduling.  In this case each component connection of the
           QoS class will receive frame based scheduling. For correct
           distribution of bandwidth, each QoS class that requires
           frame-based scheduling should have its own waiting room.
      M: VC Merging
           Bit 6 of the Scheduler Flags field, if set, indicates that
           the scheduler on this output port is capable of VC merging
           by a mechanism other than frame-based scheduling. VC
           merging indicates that the switch is capable of the
           multipoint-to-point merging of two or more incoming virtual
           connections onto a single outgoing virtual connection
           without interleaving cells from different AAL-5 packets
           that bear the same VPI/VCI. VC merging differs from frame-
           based scheduling in that cells with a different VPI/VCI may
           be interleaved with those of a multipoint-to-point VC
           merging connection. Thus, higher priority cells may be
           interleaved during the transmission of a packet on a lower
           priority VC merging connection.  Most switches achieve VC
           merging by using frame-based scheduling.  VC merging is a
           property of the waiting room and is requested in the

Newman, et. al. Informational [Page 69] RFC 2297 Ipsilon's General Switch Management March 1998

           Scheduler Establishment message.  A QoS class may be routed
           through a waiting room configured with VC merging.  In this
           case each component connection of the QoS class will
           receive VC merging.
      B: Shared Buffer
           Bit 7 of the Scheduler Flags field, if set, indicates that
           at least some of the buffer space specified by the Max
           Buffer field is shared with other ports.  If zero, it
           indicates that the buffer space specified by the Max Buffer
           field is not shared with other ports.
      I: Identical Ports
           Bit 8 of the Scheduler Flags field, if set, indicates that
           all ports of the switch have identical QoS capabilities. If
           this bit is set the controller does not have to request the
           QoS configuration of each port individually as all ports
           have the same capability.
      x: Bits 9--15 of the Scheduler Flags field are not used.
 Regulator Flags
       0                   1
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |C|Q|I O|P|S|H|M|x x x x x x x x|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      C: Connection Policing
           Bit 0 of the Regulator Flags field indicates that this
           input port supports the policing of individual incoming
           connections. The parameters for the policer are specified
           in the QoS Connection Management message when the
           connection is established.
      Q: QoS Class Policing
           If bit 1 of the Regulator Flags field is set, a policer
           function is available to police each QoS class on output
           from the classifier. The parameters for this policer are
           specified in the QoS Class Establishment message. If this
           bit is zero, no policer function is available to police a
           QoS class.
      IO: QoS Class Location
           Bits 2 and 3 of the Regulator Flags field specify the
           location of the classifier and regulator functions. If both

Newman, et. al. Informational [Page 70] RFC 2297 Ipsilon's General Switch Management March 1998

           bits 2 and 3 of the Regulator Flags field are zero, no
           classifier or regulator function is available to this port.
           If bit 2 of the Regulator Flags field is set and bit 3 is
           zero, the classifier and regulator functions are available
           on the input port. This implies that only virtual
           connections arriving at this input port may be grouped into
           QoS classes by this classifier. However, connections in a
           QoS class output from this regulator may be switched to any
           output port.
           If bit 2 of the Regulator Flags field is zero and bit 3 is
           set, the classifier and regulator functions are available
           on the output port. This implies that virtual connections
           arriving at any input port may be grouped into QoS classes
           by this classifier. However, all connections in any QoS
           class output from this regulator may only be switched to
           this output port.
           If both bits 2 and 3 of the Regulator Flags field are set,
           this switch port has access to centralized classifier and
           regulator functions. This implies that virtual connections
           arriving at any input port may be grouped into a QoS class
           by this classifier. Also, connections in a QoS class output
           from this regulator may be switched to any output port.
      Regulator Function
      P: If bit 4 of the Regulator Flags field is set, the regulator
           is able to support the policing function.
      S: If bit 5 of the Regulator Flags field is set, the regulator
           is able to support the shaping function on all priority
           levels of the scheduler.
      H: If bit 5 of the Regulator Flags field is zero and bit 6 is
           set, the regulator is able to support the shaping function
           but only on the highest priority level of the scheduler.
           All connections and QoS classes using this regulator must
           be routed to a waiting room at the highest priority level
           of the scheduler.
      M: QoS Multicast
           If bit 7 of the Regulator Flags field is set, any point-
           to-multipoint connection arriving on this input port, with
           QoS parameters established by the GSMP Quality of Service
           messages, must use the same QoS parameters for all output
           branches.

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      x: Bits 8--15 of the Regulator Flags field are not used.
 Excess Capabilities
       0                   1
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |D|T|S|A|B|x x x x x x x x x x x|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      Policer:
      D: If bit 0 of the Excess Capabilities field is set, the policer
           function of the regulator is able to support discard.
      T: If bit 1 of the Excess Capabilities field is set, the policer
           function of the regulator is able to support tagging.
      S: If bit 2 of the Excess Capabilities field is set, the policer
           function of the regulator is able to support differentiated
           scheduling.
      Shaper:
      A: If bit 3 of the Excess Capabilities field is set, the shaper
           function of the regulator is able to support tagging.
      B: If bit 4 of the Excess Capabilities field is set, the shaper
           function of the regulator is able to support differentiated
           scheduling.
      x: Bits 5--15 of the Excess Capabilities field are not used.
 Hi Sharing
 Lo Sharing
           Defines a range of priority levels that support weighted
           sharing. Each priority level in the range Lo Sharing to Hi
           Sharing inclusive, supports weighted sharing. A priority
           level that supports weighted sharing offers a weighted
           sharing algorithm (for example, weighted round-robin)
           between waiting rooms within that priority level. This
           permits the output link bandwidth available at that
           priority level, to be shared between the waiting rooms
           allocated to that priority level, according to the Net
           Weight parameter of each waiting room.  The value 0xFF for
           both parameters indicates that this output port does not
           support weighted sharing in any priority level.

Newman, et. al. Informational [Page 72] RFC 2297 Ipsilon's General Switch Management March 1998

 Max Classes
           If bit 3 of the Scheduler Flags field is zero, Max Classes
           gives the maximum number of QoS classes that may be
           supported by this switch port. In this case the maximum
           number of QoS classes that may be supported by this switch
           port is not affected by the number of QoS classes in use by
           other switch ports.  If bit 3 of the Scheduler Flags field
           is set, Max Classes gives the maximum number of QoS classes
           that may be supported by the entire switch. In this case it
           is assumed that use of these QoS classes may be distributed
           among the various switch ports.
 Default Size
           The size of waiting room that this output port allocates by
           default. The actual size of waiting room may be specified
           in the Scheduler Establishment message. The size of a
           waiting room specifies the maximum number of cells
           permitted to wait for transmission via that waiting room.
           Any further cells arriving at that waiting room beyond this
           number will be discarded.
 Default Discard Threshold
           The value of discard threshold that this output port
           allocates by default. The actual value of discard threshold
           may be specified in the Scheduler Establishment message.
           The discard threshold specifies the number of cells waiting
           for transmission via a waiting room after which further
           arriving cells will be subject to a discard mechanism.
 Max Buffer
           The maximum amount of buffer space, measured in cells,
           available to this port. If bit 7 of the Scheduler Flags
           field is zero this, buffer space is not shared with other
           ports. If bit 7 of the Scheduler Flags field is set, at
           least some of this buffer space is shared with other ports.
 Max Shaper Buffer
           The maximum amount of buffer space, measured in cells,
           available to a QoS connection or a QoS class within the
           shaper function of the regulator. This shaper buffer space
           is likely to be shared among all QoS classes and QoS
           connections using the shaper, so there is no guarantee that
           the amount of buffer space defined by the Max Shaper Buffer
           field will be available to any particular QoS class or QoS
           connection.

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 Scaling Factor
           The QoS Class Establishment and QoS Connection Management
           messages require parameters that describe cell rates in
           cells per second or their reciprocal, cell interarrival
           periods, in seconds per cell. In order that these
           parameters may be specified with a 32-bit unsigned integer,
           the switch defines a Scaling Factor to be used in defining
           such parameters. By appropriate choice of the Scaling
           Factor the switch can select the range and granularity of
           rate or time that can be specified with the 32-bit unsigned
           integer.  Further details are given in the discussion of
           the UPC Parameters field of the QoS Connection Management
           message.

9.3 Scheduler Establishment Message

 The Scheduler Establishment message is used to configure the
 scheduler on a specified output port. It is used to configure a
 waiting room, attach it to a leaf of the scheduler tree, and return a
 Scheduler Identifier to reference the waiting room. The Scheduler
 Establishment message may also be used to modify the parameters of an
 already established waiting room.
 Scheduler Identifiers in the range 0--255 represent default values.
 They are used for the priority levels that may be specified in the
 Class of Service field of Connection Management messages without
 requiring explicit establishment via a Scheduler Establishment
 message.  Each of these default values specifies a single waiting
 room with default parameters, configured as a FIFO queue, on each of
 the valid scheduler priority levels. (This permits Connection
 Management messages to continue to specify QoS requirements as a
 priority without requiring the use of any of the QoS messages.) The
 number of priority levels available to the scheduler is specified in
 the Priorities field of the Port Configuration and All Ports
 Configuration messages.
 The Scheduler Establishment Message is:
    Message Type = 97
 The Scheduler Establishment request and success response messages
 have the following format:

Newman, et. al. Informational [Page 74] RFC 2297 Ipsilon's General Switch Management March 1998

  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                             Port                              |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      Port Session Number                      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Scheduler Identifier      |          Net Weight           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |           Reserved            |D|F|M|W|x x x x|   Priority    |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                       Waiting Room Size                       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                       Discard Threshold                       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Scheduler Identifier
           The Scheduler Identifier is selected by the controller. It
           is used to identify the waiting room being established or
           modified in future messages. The Scheduler Identifier is
           taken from a namespace that is local to the switch port. A
           Scheduler Identifier in the Scheduler Establishment message
           must be greater than 0x00FF but less than 0xFFFF. The
           values 0 -- 0x00FF are reserved for use as default values.
           The default values of the Scheduler Identifier are used to
           specify the default settings for the scheduler. Each of the
           default values maps directly to one of the scheduler
           priority levels.  The value 0xFFFF is reserved for use in
           the QoS Connection Management message.
 Net Weight
           The Net Weight specifies the share of the bandwidth
           available to the priority level, specified by the Priority
           field, that should be given to this waiting room.  The Net
           Weight parameter is only valid if the priority level
           specified by the Priority field supports weighted sharing.
           The Net Weight is an unsigned 16-bit field specifying a
           binary fraction.  I.e. the bandwidth share, as a fraction
           of the bandwidth available to the priority level, is given
           by:
              Bandwidth share = Net Weight * 2**(-16)

Newman, et. al. Informational [Page 75] RFC 2297 Ipsilon's General Switch Management March 1998

           A Net Weight of zero indicates equal sharing between all
           waiting rooms sharing this priority level that request a
           Net Weight of zero.  While a 16-bit field is used to
           specify the Net Weight it is understood that the accuracy
           of the bandwidth sharing is hardware dependent and is not
           specified.
           If weighted sharing is not required at a particular
           priority level, a waiting room with a Net Weight value of
           0xFFFF must be specified for that priority level. A
           priority level that does not support weighted sharing can
           only support a single waiting room.
 Flags
      D: Packet Discard
           Bit 0 of the Flags field, if set, indicates that packet
           discard is required on all connections and QoS classes
           routed through this waiting room.
      F: Frame-Based Scheduling
           Bit 1 of the Flags field, if set, indicates that frame-
           based scheduling is required on all connections and QoS
           classes routed through this waiting room.  In frame-based
           scheduling, a connection is only scheduled for transmission
           when a complete AAL-5 packet is available.  When a
           connection is scheduled for transmission, all cells
           belonging to one or more complete packets from that
           connection will be transmitted without being interleaved
           with any other cells on that output port. A QoS class may
           be routed through a waiting room configured with frame-
           based scheduling.  In this case each component connection
           of the QoS class will receive frame based scheduling. For
           correct distribution of bandwidth, each QoS class that
           requires frame-based scheduling should have its own waiting
           room.
      M: VC Merging
           Bit 2 of the Scheduler Flags field, if set, indicates that
           VC merging is required on all connections and QoS classes
           routed through this waiting room.  VC merging enables the
           multipoint-to-point merging of two or more incoming virtual
           connections onto a single outgoing virtual connection,
           without interleaving cells from different AAL-5 packets
           that bear the same VPI/VCI. VC merging differs from frame-
           based scheduling in that cells with a different VPI/VCI may
           be interleaved with those of a multipoint-to-point VC
           merging connection.  Most switches achieve VC merging by

Newman, et. al. Informational [Page 76] RFC 2297 Ipsilon's General Switch Management March 1998

           using frame-based scheduling.  A QoS class may be routed
           through a waiting room configured with VC merging.  In this
           case each component connection of the QoS class will
           receive VC merging.
      W: Weighted Scheduling
           Bit 3 of the Flags field, if set, indicates that weighted
           scheduling is required on all connections and QoS classes
           routed through this waiting room.  All connections and QoS
           classes routed through this waiting room will require a
           Connection Weight or a QoS Class Weight respectively. The
           Connection Weight is specified in the QoS Connection
           Management message. The QoS Class Weight is specified in
           the QoS Class Establishment message. If weighted scheduling
           within this waiting room is unavailable, a failure response
           message must be returned indicating, "Weighted scheduling
           within this waiting room is unavailable."
           Bit 3 of the Flags field, if zero, indicates that this
           waiting room should be configured as a single FIFO queue.
           All cells arriving at this waiting room will receive
           first-in-first-out service. If Frame-Based Scheduling or VC
           Merging are also selected, the strict first-in-first-out
           service discipline will be modified by the requirement to
           support Frame-Based Scheduling or VC Merging.
      x: Bits 4--7 of the Flags field are not used.
 Priority
           Specifies the priority level in the scheduler to which the
           waiting room should be attached. Priorities are numbered
           from zero, with priority level zero being the highest
           priority.
 Waiting Room Size
           The required size of the waiting room.  The size of a
           waiting room specifies the maximum number of cells
           permitted to wait for transmission via that waiting room.
           Any further cells arriving at that waiting room beyond this
           number will be discarded. If the switch is unable to grant
           the size requested in the Scheduler Establishment request
           message it may reply with the actual size allocated to the
           waiting room in the Waiting Room Size field of the success
           response message.  A value of zero for the Waiting Room
           Size indicates that the default value should be used.

Newman, et. al. Informational [Page 77] RFC 2297 Ipsilon's General Switch Management March 1998

 Discard Threshold
           The required value of the discard threshold.  The discard
           threshold specifies the number of cells waiting for
           transmission via a waiting room after which further
           arriving cells will be subject to a discard mechanism. The
           value of the Discard Threshold must be less than or equal
           to the value of the Waiting Room Size parameter for any
           given waiting room. If the switch is unable to grant the
           value of discard threshold requested in the Scheduler
           Establishment request message it may reply with the actual
           value of discard threshold allocated to the waiting room in
           the Discard Threshold field of the success response
           message.  A value of zero for the Discard Threshold
           indicates that the default value should be used.

9.4 QoS Class Establishment Message

 The QoS Class Establishment message is used to configure a QoS class
 on a specified port or to modify the parameters of an already
 established QoS class.  It configures the classifier and the
 regulator functions for the QoS class. It also configures the QoS
 class policer if a policing function is available for QoS classes.
 Two styles of QoS class are available. In one style each component
 connection of the QoS class may be routed independently to an output
 port and waiting room specified in its connection management message.
 In this case the Scheduler Identifier, and if required, the Excess
 Scheduler Id, are specified in the QoS Connection Management message
 that references this style of QoS class.  In the alternative style of
 QoS class, all component connections in the QoS class are routed to
 the same waiting room on the same output port. In this case the
 Output Port, the Scheduler Identifier, and if required, the Excess
 Scheduler Id, are specified in the QoS Class Establishment message.
 The classifier and regulator functions must be located together,
 either on an input port, on an output port, or centralized. Each port
 declares the location of its classifier and regulator functions at
 initialization using the QoS Configuration message. If the classifier
 and regulator functions are located on an input port, only
 connections that arrive at that input port may join a QoS class
 established on that port. However, each connection that is part of a
 QoS class established on that port may be switched to a different
 output port. If the classifier and regulator functions are located on
 an output port, connections that arrive at any input port may join a
 QoS class established on that port. However, all connections within a
 QoS class established on that port must be switched to that output
 port. For a centralized classifier and regulator function, there is

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 no restriction on the input ports on which connections in a QoS class
 must arrive, or on the output ports to which connections in a QoS
 class must be switched.  (For the case of a centralized classifier
 and regulator the actual port specified in the QoS Class
 Establishment message is used only for administrative purposes.  Any
 valid value of Port and Port Session Number, that specifies a
 centralized classifier and regulator function, may be used.)
 The QoS Class Establishment message is:
    Message Type = 98
 The QoS Class Establishment request and success response messages
 have the following format:
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                             Port                              |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      Port Session Number                      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      QoS Class Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |   Regulator   | Excess Action |       QoS Class Weight        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Scheduler Identifier      |      Excess Scheduler Id      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                          Output Port                          |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 ~                 QoS Class Policer Parameters                  ~
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 ~                QoS Class Regulator Parameters                 ~
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 QoS Class Identifier
           The QoS Class Identifier is selected by the controller. It
           is used to identify the QoS class being established or
           modified, in future QoS Connection Management and QoS Class
           Establishment messages.  It is taken from a namespace that

Newman, et. al. Informational [Page 79] RFC 2297 Ipsilon's General Switch Management March 1998

           is global across the entire switch. No two QoS classes may
           have the same QoS Class Identifier regardless of the switch
           ports on which they are defined. A QoS Class Identifier in
           a QoS Class Establishment message must be greater than 0
           and less than 0xFFFFFFFF.
 Regulator
           The Regulator field specifies which function is required of
           the regulator.  Three possible functions are currently
           defined: none, policing, and shaping.
              None:      Regulator = 1
              Policing:  Regulator = 2
              Shaping:   Regulator = 3
           If the Regulator function is specified as none, no
           operations are performed by the regulator on the cells
           output from the classifier. Cells output from the
           classifier are transferred directly to the waiting room
           specified by the Scheduler Identifier.
           If policing is specified, a token bucket policer will be
           applied to the QoS class. The policer determines which
           cells conform to the specified policer traffic parameters
           and which do not. Conforming cells are transferred directly
           to the waiting room specified by the Scheduler Identifier.
           The action to be taken by the policer on the excess traffic
           is specified by the Excess Action field. The policer
           traffic parameters are specified in the QoS Class Regulator
           Parameters fields.
           If shaping is specified, traffic shaping will be applied to
           the QoS class.  Cells in a QoS class should leave the
           regulator spaced evenly apart at a rate defined by the QoS
           Class Regulator Parameters fields.  These cells are
           transferred directly to the waiting room specified by the
           Scheduler Identifier.  The jitter on the conforming cell
           stream on exit from the shaping function of the regulator
           is not specified.
 Excess Action
       0 1 2 3 4 5 6 7
      +-+-+-+-+-+-+-+-+
      |T|D|S|x x x x x|
      +-+-+-+-+-+-+-+-+

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      T: Tagging
           If bit 0 of the Excess Action field is set, all cells
           transferred to the waiting room specified by the Excess
           Scheduler Id will have their CLP bit set. If bit 0 of the
           Excess Action field is zero, the CLP bit of cells
           transferred to the waiting room specified by the Excess
           Scheduler Id will remain unchanged.
      D: Discard
           This function is only available if policing is selected as
           the regulator function.  If the Regulator field specifies
           Policing, and bit 1 of the Excess Action field is set, all
           cells determined by the policer to be in excess of the
           traffic parameters must be discarded. In this case the
           Excess Scheduler Id is not used and bit 0 of the Excess
           Action field should be ignored.
      S: Differentiated Scheduling
           This function operates differently according to whether
           policing or shaping is selected as the regulator function.
           If the Regulator field specifies Policing, and bit 1 of the
           Excess Action field is zero, and bit 2 of the Excess Action
           field is set, all cells determined by the policer to be in
           excess of the traffic parameters must be transferred to the
           waiting room specified by the Excess Scheduler Id.  In this
           case care must be taken in the implementation to ensure
           that within each virtual path connection or virtual channel
           connection, cells depart in the same order that they
           arrived.  If the Regulator field specifies Policing, and
           bit 1 of the Excess Action field is zero, and bit 2 of the
           Excess Action field is zero, all cells determined by the
           policer to be in excess of the traffic parameters must be
           transferred to the waiting room specified by the Scheduler
           Identifier.  In this case the Excess Scheduler Id is not
           used.
           If the Regulator field specifies Shaping, and bit 2 of the
           Excess Action field is zero, cells will be transferred from
           the QoS class to the waiting room pointed to by the
           Scheduler Identifier at a rate defined by the QoS Class
           Regulator Parameters. In this case the Excess Scheduler Id
           is not used.  If the Regulator field specifies Shaping, and
           bit 2 of the Excess Action field is set, additional cells
           will be scheduled for transmission by the waiting room
           pointed to by the Excess Scheduler Id. This permits a
           minimum cell rate to be allocated to the QoS class using
           the QoS Class Regulator Parameters and additional bandwidth

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           to be shared by the QoS class. The additional share of
           bandwidth is determined according to the parameters of the
           waiting room pointed to by the Excess Scheduler Id. If the
           Excess Scheduler Id is specified in the QoS Class
           Establishment message, the additional bandwidth will be
           shared by the entire QoS class. If the Excess Scheduler Id
           is specified in each individual QoS Connection Management
           message, the additional bandwidth is specific to that
           connection and not shared by the entire QoS class. Care
           must be taken in the implementation to ensure that within
           each virtual path connection or virtual channel connection,
           cells depart in the same order that they arrived.
      x: Bits 3--7 of the Excess Action field are not used.
 QoS Class Weight
           If bit 1 of the Scheduler Flags field of the QoS
           Configuration message indicates that weighted service may
           be applied to a QoS class, the QoS Class Weight parameter
           specifies the share of the bandwidth available to the
           waiting room that should be given to this QoS class.
           The QoS Class Weight is an unsigned 16-bit field specifying
           a binary fraction.  I.e. the bandwidth share, as a fraction
           of the bandwidth available to the waiting room, is given
           by:
              Bandwidth share = QoS Class Weight * 2**(-16)
           A QoS Class Weight of zero indicates equal sharing between
           all QoS classes sharing this waiting room that request a
           QoS Class Weight of zero.  While a 16-bit field is used to
           specify the QoS Class Weight it is understood that the
           accuracy of the bandwidth sharing is hardware dependent and
           is not specified.
           If the Regulator field of the QoS Class Establishment
           message indicates None, or Policer, the QoS Class Weight
           should be applied to the waiting room pointed to by the
           Scheduler Identifier. If the Regulator field of the QoS
           Class Establishment message indicates Shaper, the QoS Class
           Weight should be applied to the waiting room pointed to by
           the Excess Scheduler Id.
           If the specified waiting room is unable to offer weighted
           sharing for a QoS class, a failure response message should
           be returned with the failure code indicating: "This waiting
           room is unable to offer weighted sharing for a QoS class."

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 Scheduler Identifier
           If all conforming traffic from this QoS class is directed
           to the same waiting room, on the same output port, this
           field specifies the Scheduler Identifier for the entire QoS
           class. The Scheduler Identifier points to the waiting room,
           on the output port specified by the Output Port field, to
           which all conforming traffic should be sent.  If this field
           is not used it should be set to 0xFFFF. If each component
           connection of the QoS class specifies its own output port
           and waiting room, the Scheduler Identifier must be
           specified in the QoS Connection Management message and this
           field must be set to 0xFFFF.
 Excess Scheduler Id
           If all conforming traffic from this QoS class is directed
           to the same waiting room, on the same output port, this
           field specifies the Excess Scheduler Id for the entire QoS
           class. The Excess Scheduler Id points to the waiting room,
           on the output port specified by the Output Port field, to
           which all excess traffic should be sent.  If this field is
           not used it should be set to 0xFFFF. If each component
           connection of the QoS class specifies its own output port
           and waiting room, the Excess Scheduler Id must be specified
           in the QoS Connection Management message and this field
           must be set to 0xFFFF. If the Scheduler Id is specified in
           the QoS Class Establishment message, the Excess Scheduler
           Id must also be specified in the QoS Class Establishment
           message (or not used). If the Scheduler Id is specified in
           the QoS Connection Management message, the Excess Scheduler
           Id must also be specified in the QoS Connection Management
           message (or not used). The Excess Scheduler Id must not
           point to the same waiting room on the same output port as
           the Scheduler Identifier.
 Output Port
           If the Scheduler Identifier field in the QoS Establishment
           message is not 0xFFFF the Output Port field specifies the
           Output Port to which traffic from this QoS class should be
           routed. If the Scheduler Identifier field in the QoS
           Establishment message is 0xFFFF, this field is not used.
 QoS Class Policer Parameters
           A policer function may be applied to a QoS class on output
           from the classifier independently of the regulator
           function.  The QoS class policer function is identical to
           the connection policer function defined in the QoS

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           Connection Management message with the exception that it
           applies to all cells that belong to the QoS class rather
           than just cells that belong to a single connection.
           The QoS Class Policer Parameters have the following format:
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                     QoS Class Increment-1                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                       QoS Class Limit-1                       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                     QoS Class Increment-2                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                       QoS Class Limit-2                       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                  Reserved                     |C|A|x x x x x x|
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
           The definition of these fields is given in the UPC
           Parameters section of the QoS Connection Management
           message.
 QoS Class Regulator Parameters
           The QoS class regulator function is identical to the
           regulator function defined in the QoS Connection Management
           message with the exception that it applies to all cells
           that belong to the QoS class rather than just cells that
           belong to a single connection.
           The QoS Class Regulator Parameters have the following
           format:
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                QoS Class Regulator Increment                  |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                  QoS Class Regulator Limit                    |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
           The definition of these fields is given in the Regulator
           Parameters section of the QoS Connection Management
           message.

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9.5 QoS Release Message

 The QoS Release message is used to delete a Scheduler Identifier or a
 QoS Class Identifier and to release all resources associated with it.
 The QoS Release message is:
    Message Type = 99
 The QoS Release request and success response messages have the
 following format:
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                             Port                              |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      Port Session Number                      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |           Reserved            |     Scheduler Identifier      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      QoS Class Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Port
           If the QoS Release message contains a Scheduler Identifier,
           the Port field must contain the Port Number of the switch
           output port to which the Scheduler Identifier applies. If
           the QoS Release message contains a QoS Class Identifier,
           any valid Port number may be used. (The QoS Class
           Identifier has a global namespace.)
 Port Session Number
           The current Port Session Number for the port specified in
           the Port field.
 Scheduler Identifier
           If the Scheduler Identifier contains the value 0xFFFF the
           QoS Class Identifier specified in the QoS Class Identifier
           field should be released.  Else, if the value of the
           Scheduler Identifier lies in the range 0x0100 -- 0xFFFE
           inclusive, the Scheduler Identifier specified by the
           Scheduler Identifier field should be released.  A Scheduler

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           Identifier with a value less than 0x0100 is invalid in a
           QoS Release message.  (It specifies a default value which
           may not be released.)
 QoS Class Identifier
           If the Scheduler Identifier contains the value 0xFFFF the
           QoS Class Identifier field specifies the QoS Class
           Identifier to be released.
 If the QoS Release message requests that a Scheduler Identifier be
 released, and the Scheduler Identifier is still in use by one or more
 established connections, a failure response must be returned with the
 failure code indicating: "Scheduler Identifier still in use." If the
 QoS Release message requests that a QoS Class Identifier be released,
 and the QoS Class Identifier is still in use by one or more
 established connections, a failure response must be returned with the
 failure code indicating: "QoS Class Identifier still in use."

9.6 QoS Connection Management Message

 The QoS Connection Management message is used by the controller to
 establish and modify virtual channel connections and virtual path
 connections across the switch which require QoS parameters to be
 specified. The functionality of the QoS Connection Management message
 is identical to that of the Add Branch connection management message
 with the additional specification of QoS parameters.  No specific QoS
 connection release messages are defined. QoS connections may be
 released with the Delete Tree, Delete All, and Delete Branches
 messages defined in Section 4, "Connection Management Messages." When
 a QoS connection is released, all associated QoS resources are
 released.
 There are three styles of connection with specified QoS parameters:
 QoS Connection:
    This connection style specifies its own individual QoS parameters
    and is routed independently to the waiting room and output port
    specified in the QoS Connection Management message. It is not a
    member of a QoS class. Each output branch of a point-to-multipoint
    QoS connection may specify its own QoS parameters which may be
    different from all other output branches of that point-to-
    multipoint QoS connection, if the switch supports this capability.
    However, all output branches must specify identical connection
    policer parameters. A QoS Connection Management message requesting
    this style of connection is identified by a QoS Class Identifier
    with the value 0xFFFFFFFF.

Newman, et. al. Informational [Page 86] RFC 2297 Ipsilon's General Switch Management March 1998

 QoS Class Connection:
    This connection style does not specify its own individual QoS
    parameters. It is a member of a QoS class, and the QoS parameters
    are specified by the QoS class.  It is, however, routed
    independently to the waiting room and output port specified in the
    QoS Connection Management message.  Each output branch of a
    point-to-multipoint QoS Class Connection must use the same QoS
    parameters. A QoS Connection Management message requesting this
    style of connection will have a valid QoS Class Identifier and a
    valid Scheduler Identifier.
 QoS Class Member:
    This connection style does not specify its own individual QoS
    parameters. It is a member of a QoS class, and the QoS parameters
    are specified by the QoS class.  The QoS class also specifies the
    waiting room and output port to which all members of the class are
    routed. This style of connection does not support point-to-
    multipoint connections. A QoS Connection Management message
    requesting this style of connection will have a valid QoS Class
    Identifier and a Scheduler Identifier with the value 0xFFFF.
 To request a virtual channel connection with specified QoS
 parameters, the Virtual Channel Connection (VCC) QoS Connection
 Management message is:
    Message Type = 100.
 To request a virtual path connection with specified QoS parameters,
 the Virtual Path Connection (VPC) QoS Connection Management message
 is:
    Message Type = 101.
 The QoS Connection Management message has the following format for
 both request and response messages:

Newman, et. al. Informational [Page 87] RFC 2297 Ipsilon's General Switch Management March 1998

  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |    Result     |     Code      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Transaction Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      Port Session Number                      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                          Input Port                           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |M|Q|B|C|      Input VPI        |          Input VCI            |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                          Output Port                          |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |x x x x|      Output VPI       |          Output VCI           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |      Number of Branches       |     Scheduler Identifier      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      QoS Class Identifier                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |   Regulator   | Excess Action |       Connection Weight       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |S|A|x x x x x x|   Reserved    |      Excess Scheduler Id      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 ~                         UPC Parameters                        ~
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                                                               |
 ~                      Regulator Parameters                     ~
 |                                                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Port Session Number
 Input Port
 Input VPI
 Input VCI
 Output Port
 Output VPI
 Output VCI
 Number of Branches
           The definition of these fields is exactly the same as
           defined for the Add Branch message in Section 4.1,
           "Connection Management Messages."

Newman, et. al. Informational [Page 88] RFC 2297 Ipsilon's General Switch Management March 1998

 M B C Flags
           The definition of the M, B, and C flags is exactly the same
           as defined in Section 4, "Connection Management Messages."
           They apply to the QoS Connection Management message exactly
           as defined for the Add Branch message.
 Q: QoS Profile Flag The QoS Profile flag is not used in the QoS
           Connection Management message.
 Scheduler Identifier
           For QoS Connection and QoS Class Connection styles, the
           Scheduler Identifier points to the waiting room, on the
           output port specified by the Output Port field, to which
           all conforming traffic on the connection should be routed.
           The values 0 -- 255 specify the default settings for the
           scheduler. Each of the default values maps directly to one
           of the scheduler priority levels. A Scheduler Identifier in
           the range 0 -- 255 may be used without first being
           established by a Scheduler Establishment message. All
           Scheduler Identifiers in the range 0x0100 to 0xFFFE must
           first be established by a Scheduler Establishment message.
           A Scheduler Identifier with a value of 0xFFFF indicates
           that a QoS Class Member connection style is being
           requested. In this connection style, the waiting room and
           output port are specified by reference to the QoS class
           specified by the QoS Class Identifier field. In this case
           the QoS Class Identifier field must contain a valid QoS
           Class Identifier.
 QoS Class Identifier
           For QoS Class Connection and QoS Class Member connection
           styles, the QoS Class Identifier specifies the QoS Class to
           which the connection belongs. It must first be established
           by a QoS Class Establishment message and must have a value
           greater than 0 and less than 0xFFFFFFFF.
           A QoS Class Identifier with a value of 0xFFFFFFFF indicates
           that a connection of style "QoS Connection" is being
           requested. In this connection style, the connection does
           not belong to a QoS class. All QoS parameters are specified
           by the QoS Connection Management message and apply only to
           the specified connection.
 Regulator
 Excess Action
           The Regulator and Excess Action parameters are only used in
           connection requests of style "QoS Connection." The

Newman, et. al. Informational [Page 89] RFC 2297 Ipsilon's General Switch Management March 1998

           definition of these fields in the QoS Connection Management
           message is exactly the same as defined for the QoS Class
           Establishment message with the exception that they apply to
           an individual connection rather than to an entire QoS
           class.
 Connection Weight
           This field is only used in connections of style "QoS
           Connection" and "QoS Class Connection." For QoS Class
           Member style connections, the QoS Class Weight parameter of
           the QoS Class Establishment message should be used to
           assign a weight to the QoS Class.
           If bit 0 of the Scheduler Flags field of the QoS
           Configuration message indicates that weighted service may
           be applied to a connection, the Connection Weight parameter
           specifies the share of the bandwidth available to the
           waiting room that should be given to this connection.
           The Connection Weight is an unsigned 16-bit field
           specifying a binary fraction.  I.e. the bandwidth share, as
           a fraction of the bandwidth available to the waiting room,
           is given by:
              Bandwidth share = Connection Weight * 2**(-16)
           A Connection Weight of zero indicates equal sharing between
           all connections in this waiting room that request a
           Connection Weight of zero.  While a 16-bit field is used to
           specify the Connection Weight it is understood that the
           accuracy of the bandwidth sharing is hardware dependent and
           is not specified.
           For connections of style "QoS Class Connection," if the
           Regulator function of the QoS Class is specified as None,
           or Policer, the Connection Weight should be applied to the
           waiting room pointed to by the Scheduler Identifier field
           in the QoS Connection Management message. If the Regulator
           function of the QoS Class is specified as Shaper, the
           Connection Weight should be applied to the waiting room
           pointed to by the Excess Scheduler Id field in the QoS
           Connection Management message.
           For connections of style "QoS Connection," if the Regulator
           field of the QoS Connection Management message specifies
           None, or Policer, the Connection Weight should be applied
           to the waiting room pointed to by the Scheduler Identifier
           field. If the Regulator field of the QoS Connection

Newman, et. al. Informational [Page 90] RFC 2297 Ipsilon's General Switch Management March 1998

           Management message specifies Shaper, the Connection Weight
           should be applied to the waiting room pointed to by the
           Excess Scheduler Id field.
           If the specified waiting room is unable to offer weighted
           sharing for a connection, a failure response message should
           be returned with the failure code indicating: "this waiting
           room is unable to offer weighted sharing for a connection."
 QoS Flags
      S: Selective Discard
           If the Selective Discard flag is set, only cells with the
           Cell Loss Priority (CLP) bit set will be subject to the
           discard mechanism when the number of cells in the waiting
           room exceeds the Discard Threshold.  If the Selective
           Discard flag is zero, all cells (CLP=0 and CLP=1) will be
           subject to the discard mechanism when the number of cells
           in the waiting room exceeds the Discard Threshold.
           Selective discard can be combined with packet discard. In
           this case only packets in which at least one cell has the
           CLP bit set will be subject to the discard mechanism.
      A: All Branches
           For a QoS Connection Management message that specifies a
           point-to-multipoint connection, if the All Branches flag is
           set, all branches of the point-to-multipoint connection
           must be set to the QoS parameters specified in the message.
           If the All Branches flag is zero, only the single output
           branch specified in the message should be set to the QoS
           parameters specified in the message. For a QoS Connection
           Management message that specifies a point-to-point
           connection, the All Branches flag is not used.
      x: Unused
 Excess Scheduler Id
           For connections of style "QoS Connection" and "QoS Class
           Connection," the Excess Scheduler Id points to the waiting
           room, on the output port specified by the Output Port
           field, to which all excess traffic should be routed. The
           values 0 -- 255 specify the default settings for the
           scheduler. Each of the default values maps directly to one
           of the scheduler priority levels. An Excess Scheduler Id in
           the range 0 -- 255 may be used without first being
           established by a Scheduler Establishment message. All

Newman, et. al. Informational [Page 91] RFC 2297 Ipsilon's General Switch Management March 1998

           values of Excess Scheduler Id in the range 0x0100 to 0xFFFE
           must first be established by a Scheduler Establishment
           message.
           If this field is not used it should be set to 0xFFFF.  The
           Excess Scheduler Id must not point to the same waiting room
           on the same output port as the Scheduler Identifier.
 UPC Parameters
           All connection styles may be subject to a Usage Parameter
           Control (UPC) function, also known as a connection policer.
           The policing function is applied to each individual
           connection before it is combined with other connections
           into a QoS class by the classifier function. A policing
           function applied to an entire QoS class is defined in the
           QoS Class Establishment message.
           The connection policer is defined by reference to the
           Generic Cell Rate Algorithm (GCRA) defined by the ATM Forum
           [af-tm-0056], although any equivalent policing algorithm
           may be used. The GCRA takes two parameters, the increment
           (I) and the limit (L). The reciprocal of the increment
           (1/I) specifies the rate being policed. The limit specifies
           the burst tolerance. (For comparison with the token bucket
           policer discussed in [Partridge], the size of the token
           bucket is given by L/I.)
           Two policers in series may be specified to permit the
           policing of both peak rate and average rate (also called
           sustainable rate). The parameters for the first policer are
           Increment-1 and Limit-1. For comparison with the ATM Forum
           specification these would be used to police the Peak Cell
           Rate (PCR) and Cell Delay Variation Tolerance (CDVT)
           respectively. The parameters for the second policer are
           Increment-2 and Limit-2. For comparison with the ATM Forum
           specification these would be used to police the Sustainable
           Cell Rate (SCR), and Burst Tolerance.  (The Burst Tolerance
           may be computed from the Maximum Burst Size [af-tm-0056].)
           There are two configurations in which the two policers may
           be connected in series.  In the All Cells configuration,
           all cells (cells with the Cell Loss Priority (CLP) bit set
           to zero and cells with the CLP bit set to one) are subject
           to the policing action of both policers in series. In the
           CLP Selective configuration, all cells, both CLP=0 and
           CLP=1, are policed by the first policer; but only cells

Newman, et. al. Informational [Page 92] RFC 2297 Ipsilon's General Switch Management March 1998

           with CLP=0 are subject to policing by the second policer.
           Either tagging or discard may be specified for each of the
           policer configurations.
           The values of the parameters Increment and Limit in the UPC
           Parameters fields are given in terms of a time unit
           specified by the switch in the QoS Configuration Parameters
           message. The time unit is specified by the switch as a
           rate, the Scaling Factor, which gives the rate in cells per
           second that would result from an Increment parameter value
           of one. Thus to determine the value of the Increment
           parameter from the desired policed rate given in cells per
           second:
              Increment parameter = (Scaling_Factor)/(policed_rate)
           To determine the value of the Limit parameter from the
           desired Cell Delay Variation Tolerance (CDVT) given in
           seconds:
              Limit parameter = CDVT * Scaling_Factor
           To determine the value of the Limit parameter from the
           desired Burst Tolerance (BT) given in seconds:
              Limit parameter = BT * Scaling_Factor
           The Increment and Limit parameters are specified as 32-bit
           unsigned integers; so the choice of the Scaling Factor
           allows the switch to select the range and granularity of
           the policer parameters with respect to the line rate of the
           switch port.  For example, a SONET STS-3c (155.52 Mbps)
           switch port has a line rate of approximately 353 kcells/s.
           With a Scaling Factor value of 353,000,000 we can specify a
           policed rate slightly less than the line rate with a
           granularity of 0.1%. For a policed rate of 1 kbps we can
           still support a bucket size of 31 cells.
           The UPC Parameters have the following format:

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  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                           Increment-1                         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                             Limit-1                           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                           Increment-2                         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                             Limit-2                           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                  Reserved                     |C|A|x x x x x x|
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Increment-1
           The increment parameter for the first policer, specified as
           a 32-bit unsigned integer.  A value of zero for the
           Increment-1 parameter is used to disable the first policer.
           In this case all cells will be considered to conform to the
           traffic parameters of the first policer.
 Limit-1
           The limit parameter for the first policer, specified as a
           32-bit unsigned integer.
 Increment-2
           The increment parameter for the second policer, specified
           as a 32-bit unsigned integer.  A value of zero for the
           Increment-2 parameter is used to disable the second
           policer.  In this case all cells will be considered to
           conform to the traffic parameters of the second policer.
 Limit-2
           The limit parameter for the second policer, specified as a
           32-bit unsigned integer.
 Flags
      C: Configuration
           If the Configuration flag is set, the policer should be set
           to the All Cells configuration. If the Configuration flag
           is zero, the policer should be set to the CLP Selective
           configuration.
           In the All Cells configuration, all cells (both CLP=0 and
           CLP=1) are subject to the policing action of both policers
           in series. In the CLP Selective configuration, all cells,
           both CLP=0 and CLP=1, are policed by the first policer; but

Newman, et. al. Informational [Page 94] RFC 2297 Ipsilon's General Switch Management March 1998

           only cells with CLP=0 are subject to policing by the second
           policer. Either tagging or discard may be specified for
           each of the policer configurations.
      A: Action
           If the Action flag is zero, discard is required as the
           policing action. If the Action flag is set, tagging is
           required as the policing action.
           If tagging is selected in the All Cells configuration, any
           cell with CLP=0 in either policer, that the policer
           determines to be in excess of the specified policer
           parameters, will be changed to CLP=1. If discard is
           selected in the All Cells configuration, any cell (CLP=0 or
           CLP=1) in either policer, that the policer determines to be
           in excess of the specified policer parameters, will be
           discarded.
           In the CLP Selective configuration, the first policer is
           always set to discard any cell (CLP=0 or CLP=1) that it
           determines to be in excess of its specified policer
           parameters. If tagging is selected in the CLP Selective
           configuration, the second policer will change the CLP bit
           to CLP=1 of any cell that it determines to be in excess of
           its specified parameters. If discard is selected in the CLP
           Selective configuration, the second policer will discard
           any cell that it determines to be in excess of its
           specified parameters.
           To configure the policer for the conformance definitions
           specified by the ATM Forum [af-tm-0056] the following
           configurations are suggested:
              CBR.1:   One policer,     All Cells,        Discard
              VBR.1:   Two policers,    All Cells,        Discard
              VBR.2:   Two policers,    CLP Selective,    Discard
              VBR.3:   Two policers,    CLP Selective,    Tagging
              UBR.1:   One policer,     All Cells,        Discard
              UBR.2:   One policer,     All Cells,        Tagging.
      x: Unused
 Regulator Parameters
           Only connections of style "QoS Connection" require the
           Regulator Parameters to be specified in the QoS Connection
           Management message. For connections of style "QoS Class
           Connection" and "QoS Class Member" the Regulator Parameters
           are specified in the QoS Class Establishment message.

Newman, et. al. Informational [Page 95] RFC 2297 Ipsilon's General Switch Management March 1998

           The Regulator Parameters are specified in a similar manner
           to the UPC parameters. If the regulator function is
           specified as Policing, a single GCRA policer is applied to
           all cells (both CLP=0 and CLP=1) on the connection. The
           policer takes two parameters: an increment, the Regulator
           Increment, and a limit, the Regulator Limit. The reciprocal
           of the increment (1/I) specifies the rate being policed.
           The limit (L) specifies the burst tolerance. (For
           comparison with the token bucket policer discussed in
           [Partridge], the size of the token bucket is given by L/I.)
           The Regulator Increment and Regulator Limit parameters are
           32-bit unsigned integers. Their values are determined in
           terms of the Scaling Factor specified by the switch in the
           QoS Configuration Parameters message. To determine the
           value of the Regulator Increment parameter from the desired
           policed rate given in cells per second:
              Regulator Increment = (Scaling_Factor)/(policed_rate)
           For a policed rate (r) the GCRA policer guarantees that
           over any time period T the amount of traffic determined by
           the policer to be conforming to the traffic parameters does
           not exceed:
              rT + L/I
           The value of the Regulator Limit may be determined from
           this relation.
           If the regulator function is specified as Shaping, only the
           Regulator Increment parameter is used. The Regulator Limit
           parameter is not used. The value of the Regulator Increment
           parameter is determined in terms of the Scaling Factor
           specified by the switch in the QoS Configuration Parameters
           message. To determine the value of the Regulator Increment
           parameter from the desired shaper rate, given in cells per
           second, on output from the shaper:
              Regulator Increment = (Scaling_Factor)/(shaper_rate)
           An Increment value of zero is used to disable the policer.
           In this case all cells on that connection will be
           considered to conform to the policer traffic parameters. A
           shaper given a Regulator Increment parameter of zero will
           perform no shaping function on that connection.
 The Regulator Parameters have the following format:

Newman, et. al. Informational [Page 96] RFC 2297 Ipsilon's General Switch Management March 1998

  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      Regulator Increment                      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                        Regulator Limit                        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

9.7 QoS Failure Response Codes

 A failure response message is formed by returning the request message
 that caused the failure with the Result field in the header
 indicating failure (Result = 4) and the Code field giving the failure
 code. The failure code specifies the reason for the switch being
 unable to satisfy the request message.  The following additional
 failure codes are defined for use in response to QoS messages.
 General failure codes are specified in Section 3.2, Failure Response
 Messages.
     128: Weighted scheduling within this waiting room is unavailable.
     129: This waiting room is unable to offer weighted sharing for a
            QoS class.
     130: This waiting room is unable to offer weighted sharing for a
            connection.
     131: Scheduler Identifier still in use.
     132: QoS Class Identifier still in use.
     133: Invalid QoS parameter.
     134: Insufficient QoS resources.
     135: Any point-to-multipoint connection arriving on this input
            port must use the same QoS parameters for all output
            branches.

10. Adjacency Protocol

 The adjacency protocol is used to synchronize state across the link,
 to agree on which version of the protocol to use, to discover the
 identity of the entity at the other end of a link, and to detect when
 it changes. GSMP is a hard state protocol.  It is therefore important
 to detect loss of contact between switch and controller, and to
 detect any change of identity of switch or controller.  No GSMP
 messages other than those of the adjacency protocol may be sent
 across the link until the adjacency protocol has achieved
 synchronization.

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10.1 Packet Format

 All GSMP messages belonging to the adjacency protocol have the
 following structure:
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Version    | Message Type  |     Timer     |M|     Code    |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                          Sender Name                          |
 +                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                               |                               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
 |                         Receiver Name                         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                          Sender Port                          |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                         Receiver Port                         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                        Sender Instance                        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                       Receiver Instance                       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Version
           In the adjacency protocol the Version field is used for
           version negotiation.  In a SYN message the Version field
           always contains the highest version understood by the
           sender.  A receiver receiving a SYN message with a version
           higher than understood will ignore that message.  A
           receiver receiving a SYN message with a version lower than
           its own highest version, but a version that it understands,
           will reply with a SYNACK with the version from the received
           SYN in its GSMP Version field. This defines the version of
           the GSMP protocol to be used while the adjacency protocol
           remains synchronized. All other messages will use the
           agreed version in the Version field.
           The version number for the version of the GSMP protocol
           defined by this specification is Version = 2.
 Message Type
           The adjacency protocol is:
              Message Type = 10

Newman, et. al. Informational [Page 98] RFC 2297 Ipsilon's General Switch Management March 1998

 Timer
           The Timer field is used to inform the receiver of the timer
           value used in the adjacency protocol of the sender. The
           timer specifies the nominal time between periodic adjacency
           protocol messages. It is a constant for the duration of a
           GSMP session. The timer field is specified in units of
           100ms.
 M-Flag
           The M-Flag is used in the SYN message to indicate whether
           the sender is a master or a slave. If the M-Flag is set in
           the SYN message, the sender is a master.  If zero, the
           sender is a slave. The GSMP protocol is asymmetric, the
           controller being the master and the switch being the slave.
           The M-Flag prevents a master from synchronizing with
           another master, or a slave with another slave. If a slave
           receives a SYN message with a zero M-Flag, it must ignore
           that SYN message. If a master receives a SYN message with
           the M-Flag set, it must ignore that SYN message. In all
           other messages the M-Flag is not used.
 Code
           Field specifies the function of the message. Four Codes are
           defined for the adjacency protocol:
              SYN:     Code = 1
              SYNACK:  Code = 2
              ACK:     Code = 3
              RSTACK:  Code = 4.
 Sender Name
           For the SYN, SYNACK, and ACK messages, is the name of the
           entity sending the message. The Sender Name is a 48-bit
           quantity that is unique within the operational context of
           the device. A 48-bit IEEE 802 MAC address, if available,
           may be used for the Sender Name. If the Ethernet
           encapsulation is used the Sender Name must be the Source
           Address from the MAC header.  For the RSTACK message, the
           Sender Name field is set to the value of the Receiver Name
           field from the incoming message that caused the RSTACK
           message to be generated.
 Receiver Name
           For the SYN, SYNACK, and ACK messages, is the name of the
           entity that the sender of the message believes is at the
           far end of the link. If the sender of the message does not
           know the name of the entity at the far end of the link,
           this field should be set to zero. For the RSTACK message,

Newman, et. al. Informational [Page 99] RFC 2297 Ipsilon's General Switch Management March 1998

           the Receiver Name field is set to the value of the Sender
           Name field from the incoming message that caused the RSTACK
           message to be generated.
 Sender Port
           For the SYN, SYNACK, and ACK messages, is the local port
           number of the link across which the message is being sent.
           For the RSTACK message, the Sender Port field is set to the
           value of the Receiver Port field from the incoming message
           that caused the RSTACK message to be generated.
 Receiver Port
           For the SYN, SYNACK, and ACK messages, is what the sender
           believes is the local port number for the link, allocated
           by the entity at the far end of the link.  If the sender of
           the message does not know the port number at the far end of
           the link, this field should be set to zero. For the RSTACK
           message, the Receiver Port field is set to the value of the
           Sender Port field from the incoming message that caused the
           RSTACK message to be generated.
 Sender Instance
           For the SYN, SYNACK, and ACK messages, is the sender's
           instance number for the link. It is used to detect when the
           link comes back up after going down or when the identity of
           the entity at the other end of the link changes. The
           instance number is a 32-bit number that is guaranteed to be
           unique within the recent past and to change when the link
           or node comes back up after going down. Zero is not a valid
           instance number. For the RSTACK message, the Sender
           Instance field is set to the value of the Receiver Instance
           field from the incoming message that caused the RSTACK
           message to be generated.
 Receiver Instance
           For the SYN, SYNACK, and ACK messages, is what the sender
           believes is the current instance number for the link,
           allocated by the entity at the far end of the link. If the
           sender of the message does not know the current instance
           number at the far end of the link, this field should be set
           to zero. For the RSTACK message, the Receiver Instance
           field is set to the value of the Sender Instance field from
           the incoming message that caused the RSTACK message to be
           generated.

Newman, et. al. Informational [Page 100] RFC 2297 Ipsilon's General Switch Management March 1998

10.2 Procedure

 The adjacency protocol is described by the following rules and state
 tables.
 The rules and state tables use the following operations:
  o The "Update Peer Verifier" operation is defined as storing the
    values of the Sender Instance, Sender Port, and Sender Name fields
    from a SYN or SYNACK message received from the entity at the far
    end of the link.
  o The procedure "Reset the link" is defined as:
        1. Generate a new instance number for the link
        2. Delete the peer verifier (set to zero the values of Sender
           Instance, Sender Port, and Sender Name previously stored by
           the Update Peer Verifier operation)
        3. Send a SYN message
        4. Enter the SYNSENT state.
  o The state tables use the following Boolean terms and operators:
      A    The Sender Instance in the incoming message matches the
           value stored from a previous message by the "Update Peer
           Verifier" operation.
      B    The Sender Instance, Sender Port, and Sender Name fields in
           the incoming message match the values stored from a
           previous message by the "Update Peer Verifier" operation.
      C    The Receiver Instance, Receiver Port, and Receiver Name
           fields in the incoming message match the values of the
           Sender Instance, Sender Port, and Sender Name currently
           sent in outgoing SYN, SYNACK, and ACK messages.
      "&&" Represents the logical AND operation
      "||" Represents the logical OR operation
      "!" Represents the logical negation (NOT) operation.
  o A timer is required for the periodic generation of SYN, SYNACK,
    and ACK messages. The value of the timer is announced in the Timer
    field.  The period of the timer is unspecified but a value of one
    second is suggested.

Newman, et. al. Informational [Page 101] RFC 2297 Ipsilon's General Switch Management March 1998

    There are two independent events: the timer expires, and a packet
    arrives. The processing rules for these events are:
       Timer Expires:   Reset Timer
                        If state = SYNSENT Send SYN
                        If state = SYNRCVD Send SYNACK
                        If state = ESTAB   Send ACK
        Packet Arrives:
            If incoming message is an RSTACK:
                If (A && C && !SYNSENT) Reset the link
                Else Discard the message.
            If incoming message is a SYN, SYNACK, or ACK:
                Response defined by the following State Tables.
            If incoming message is any other GSMP message and state !=
                ESTAB:
                Discard incoming message.
                If state = SYNSENT Send SYN (Note 1)
                If state = SYNRCVD Send SYNACK (Note 1)
            Note 1: No more than two SYN or SYNACK messages should be
            sent within any time period of length defined by the
            timer.
  o State synchronization across a link is considered to be achieved
    when the protocol reaches the ESTAB state. All GSMP messages,
    other than adjacency protocol messages, that are received before
    synchronization is achieved will be discarded.

State Tables

State: SYNSENT

+======================================================================+

Condition Action New State

+====================+=====================================+===========+

SYNACK && C Update Peer Verifier; Send ACK ESTAB

+——————–+————————————-+———–+

SYNACK && !C Send RSTACK SYNSENT

+——————–+————————————-+———–+

SYN Update Peer Verifier; Send SYNACK SYNRCVD

+——————–+————————————-+———–+

ACK Send RSTACK SYNSENT

+======================================================================+

Newman, et. al. Informational [Page 102] RFC 2297 Ipsilon's General Switch Management March 1998

State: SYNRCVD

+======================================================================+

Condition Action New State

+====================+=====================================+===========+

SYNACK && C Update Peer Verifier; Send ACK ESTAB

+——————–+————————————-+———–+

SYNACK && !C Send RSTACK SYNRCVD

+——————–+————————————-+———–+

SYN Update Peer Verifier; Send SYNACK SYNRCVD

+——————–+————————————-+———–+

ACK && B && C Send ACK ESTAB

+——————–+————————————-+———–+

ACK && !(B && C) Send RSTACK SYNRCVD

+======================================================================+

State: ESTAB

+======================================================================+

Condition Action New State

+====================+=====================================+===========+

SYN SYNACK Send ACK (note 2) ESTAB

+——————–+————————————-+———–+

ACK && B && C Send ACK (note 3) ESTAB

+——————–+————————————-+———–+

ACK && !(B && C) Send RSTACK ESTAB

+======================================================================+

 Note 2: No more than two ACKs should be sent within any time period
 of length defined by the timer. Thus, one ACK must be sent every time
 the timer expires. In addition, one further ACK may be sent between
 timer expirations if the incoming message is a SYN or SYNACK. This
 additional ACK allows the adjacency protocol to reach synchronization
 more quickly.
 Note 3: No more than one ACK should be sent within any time period of
 length defined by the timer.

10.3 Loss of Synchronization

 If after synchronization is achieved, no valid GSMP messages are
 received in any period of time in excess of three times the value of
 the Timer field announced in the incoming adjacency protocol
 messages, loss of synchronization may be declared.
 The preferred procedure for a switch to use when it looses
 synchronization with its active controller is to attempt to establish

Newman, et. al. Informational [Page 103] RFC 2297 Ipsilon's General Switch Management March 1998

 synchronization with (one of) its backup controller(s).  However, in
 this preferred approach, it must not reset its state until it
 achieves synchronization with a backup controller.  This means that
 if, before achieving synchronization with a backup controller, it
 regains synchronization with its original controller, it may continue
 the original session (and cease attempting to establish
 synchronization with a backup controller). If synchronization with
 the original session is regained it is the responsibility of the
 controller to ensure consistent state between the switch and
 controller.
 While the above is the preferred procedure, it is also the case that
 the simplest procedure when declaring loss of synchronization with
 the active controller is to reset the switch state, and start
 searching for a controller.  This simple procedure is legitimate.

11. Summary of Failure Response Codes

 The following list gives a summary of the failure codes defined for
 failure response messages:
      1: Unspecified reason not covered by other failure codes.
      2: Invalid request message.
      3: The specified request is not implemented on this switch.
      4: Invalid Port Session Number.
      5: One or more of the specified ports does not exist.
      6: One or more of the specified ports is down.
      7: Unused. (This failure code has been replaced by failure codes
           18--21.)
      8: The specified connection does not exist.
      9: The specified branch does not exist.
     10: A branch belonging to the specified point-to-multipoint
           connection is already established on the specified output
           port and the switch cannot support more than a single
           branch of any point-to-multipoint connection on the same
           output port.
     11: The limit on the maximum number of point-to-multipoint
           connections that the switch can support has been reached.
     12: The limit on the maximum number of branches that the
           specified point-to-multipoint connection can support has
           been reached.
     13: Unable to assign the requested VPI/VCI value to the requested
           branch on the specified point-to-multipoint connection.
     14: General problem related to the manner in which point-to-
           multipoint is supported by the switch.
     15: Out of resources (e.g. memory exhausted, etc.).
     16: Failure specific to the particular message type. (The meaning
           of this failure code depends upon the Message Type. It is

Newman, et. al. Informational [Page 104] RFC 2297 Ipsilon's General Switch Management March 1998

           defined within the description of any message that uses
           it.)
     17: Cannot label each output branch of a point-to-multipoint tree
           with a different label.
     18: One or more of the specified input VPIs is invalid.
     19: One or more of the specified input VCIs is invalid.
     20: One or more of the specified output VPIs is invalid.
     21: One or more of the specified output VCIs is invalid.
     22: Invalid Class of Service field in a Connection Management
           message.
     23: Insufficient resources for QoS Profile.
     24: Virtual path switching is not supported on this input port.
     25: Point-to-multipoint virtual path connections are not
           supported on either the requested input port or the
           requested output port.
     26: Attempt to add a virtual path connection branch to an
           existing virtual channel connection.
     27: Attempt to add a virtual channel connection branch to an
           existing virtual path connection.
     28: Only point-to-point bidirectional connections may be
           established.
     29: Cannot support requested VPI range.
     30: Cannot support requested VCI range on all requested VPIs.
     31: The transmit cell rate of this output port cannot be changed.
     32: Requested transmit cell rate out of range for this output
           port.
    128: Weighted scheduling within this waiting room is unavailable.
    129: This waiting room is unable to offer weighted sharing for a
           QoS class.
    130: This waiting room is unable to offer weighted sharing for a
           connection.
    131: Scheduler Identifier still in use.
    132: QoS Class Identifier still in use.
    133: Invalid QoS parameter.
    134: Insufficient QoS resources.
    135: Any point-to-multipoint connection arriving on this input
           port must use the same QoS parameters for all output
           branches.

12. Summary of Message Set

 The following table gives a summary of the messages defined in this
 version of the specification. It also indicates which messages must
 be supported in a minimal implementation of the protocol. Those
 messages marked as "Required" must be supported by the switch for an
 implementation to be considered to conform to this specification.
 (While the controller should also implement those messages marked

Newman, et. al. Informational [Page 105] RFC 2297 Ipsilon's General Switch Management March 1998

 "Required," conformance cannot be tested for the controller due to
 the Master-Slave nature of the protocol.)
     Message Name                Message Type    Status
 Connection Management Messages
     Add Branch VCC....................16        Required
                VPC....................26
     Delete Tree.......................18
     Delete All........................20
     Delete Branches...................17        Required
     Move Branch VCC...................22
                 VPC...................27
 Port Management Messages
     Port Management...................32        Required
     Label Range.......................33
 State and Statistics Messages
     Connection Activity...............48
     Port Statistics...................49        Required
     Connection Statistics.............50
     QoS Class Statistics..............51
     Report Connection State...........52
 Configuration Messages
     Switch Configuration..............64        Required
     Port Configuration................65        Required
     All Ports Configuration...........66        Required
 Event Messages
     Port Up...........................80
     Port Down.........................81
     Invalid VPI/VCI...................82
     New Port..........................83
     Dead Port.........................84
 Quality of Service Messages
     QoS Configuration.................96
     Scheduler Establishment...........97
     QoS Class Establishment...........98
     QoS Release.......................99
     QoS Connection Management VCC....100
                               VPC....101
 Adjacency Protocol....................10        Required

Newman, et. al. Informational [Page 106] RFC 2297 Ipsilon's General Switch Management March 1998

REFERENCES

 [af-tm-0056] ATM Forum Traffic Management Specification 4.0, af-tm-
              0056.000, April 1996.
 [I.361]      "B-ISDN ATM Layer Specification," International
              Telecommunication Union, ITU-T Recommendation I.361,
              Mar. 1993.
 [I.363]      "B-ISDN ATM Adaptation Layer (AAL) Specification,"
              International Telecommunication Union, ITU-T
              Recommendation I.363, Mar. 1993.
 [IpsilonMIB] Ipsilon IP Switch MIB,
              http://www.ipsilon.com/products/ips.mib
 [Partridge]  C. Partridge, "Gigabit Networking," Addison-Wesley,
              1994.
 [RFC1700]    Reynolds, J., and J. Postel, "Assigned Numbers," STD 2,
              RFC 1700, October 1994.
 [RFC1987]    Newman, P, Edwards, W., hinden, R., Hoffman, E. Ching
              Liaw, F., Lyon, T. and G. Minshall, "Ipsilon's General
              Switch Management Protocol Specification," Version 1.1,
              RFC 1987, August 1996.

SECURITY CONSIDERATIONS

 Physical security on the control link connecting the controller to
 the switch is assumed. Security issues are not discussed in this
 document.

AUTHORS' ADDRESSES

 Peter Newman                        Phone: +1 (408) 990 2003
 Nokia                               EMail: pn@ipsilon.com
 W. L. Edwards, Chief Scientist      Phone: +1 (913) 534 5334
 Sprint                              EMail: texas@sprintcorp.com
 Robert M. Hinden                    Phone: +1 (408) 990 2004
 Nokia                               EMail: hinden@ipsilon.com
 Eric Hoffman                        Phone: +1 (408) 990 2010
 Nokia                               EMail: hoffman@ipsilon.com

Newman, et. al. Informational [Page 107] RFC 2297 Ipsilon's General Switch Management March 1998

 Fong Ching Liaw                     Phone: +1 (408) 873 2688
 Coppercom                           EMail: fong@coppercom.com
 Tom Lyon                            Phone: +1 (408) 990 2001
 Nokia                               EMail: pugs@ipsilon.com
 Greg Minshall                       Phone: +1 (650) 237 3164
 Fiberlane Communications            EMail: minshall@fiberlane.com

Nokia (Sunnyvale) is located at:

 232 Java Drive
 Sunnyvale, CA 94089
 USA

Sprint is located at:

 Sprint
 Sprint Technology Services - Long Distance Division
 9300 Metcalf Avenue
 Mailstop KSOPKB0802
 Overland Park, KS 66212-6333
 USA

Fiberlane Communications is located at:

 1399 Charleston Road
 Mountain View, CA 94043
 USA

Newman, et. al. Informational [Page 108] RFC 2297 Ipsilon's General Switch Management March 1998

Full Copyright Statement

 Copyright (C) The Internet Society (1998).  All Rights Reserved.
 This document and translations of it may be copied and furnished to
 others, and derivative works that comment on or otherwise explain it
 or assist in its implementation may be prepared, copied, published
 and distributed, in whole or in part, without restriction of any
 kind, provided that the above copyright notice and this paragraph are
 included on all such copies and derivative works.  However, this
 document itself may not be modified in any way, such as by removing
 the copyright notice or references to the Internet Society or other
 Internet organizations, except as needed for the purpose of
 developing Internet standards in which case the procedures for
 copyrights defined in the Internet Standards process must be
 followed, or as required to translate it into languages other than
 English.
 The limited permissions granted above are perpetual and will not be
 revoked by the Internet Society or its successors or assigns.
 This document and the information contained herein is provided on an
 "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
 TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
 BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
 HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
 MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Newman, et. al. Informational [Page 109]

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