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rfc:rfc4974

Network Working Group D. Papadimitriou Request for Comments: 4974 Alcatel Updates: 3473 A. Farrel Category: Standards Track Old Dog Consulting

                                                           August 2007
       Generalized MPLS (GMPLS) RSVP-TE Signaling Extensions
                        in Support of Calls

Status of This Memo

 This document specifies an Internet standards track protocol for the
 Internet community, and requests discussion and suggestions for
 improvements.  Please refer to the current edition of the "Internet
 Official Protocol Standards" (STD 1) for the standardization state
 and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

 Copyright (C) The IETF Trust (2007).

Abstract

 In certain networking topologies, it may be advantageous to maintain
 associations between endpoints and key transit points to support an
 instance of a service.  Such associations are known as Calls.
 A Call does not provide the actual connectivity for transmitting user
 traffic, but only builds a relationship by which subsequent
 Connections may be made.  In Generalized MPLS (GMPLS) such
 Connections are known as Label Switched Paths (LSPs).
 This document specifies how GMPLS Resource Reservation Protocol -
 Traffic Engineering (RSVP-TE) signaling may be used and extended to
 support Calls.  These mechanisms provide full and logical
 Call/Connection separation.
 The mechanisms proposed in this document are applicable to any
 environment (including multi-area), and for any type of interface:
 packet, layer-2, time-division multiplexed, lambda, or fiber
 switching.

Papadimitriou & Farrel Standards Track [Page 1] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

Table of Contents

 1. Introduction ....................................................3
    1.1. Applicability to ASON ......................................4
 2. Conventions Used in This document ...............................4
 3. Requirements ....................................................4
    3.1. Basic Call Function ........................................4
    3.2. Call/Connection Separation .................................5
    3.3. Call Segments ..............................................5
 4. Concepts and Terms ..............................................5
    4.1. What Is a Call? ............................................5
    4.2. A Hierarchy of Calls, Connections, Tunnels, and LSPs .......6
    4.3. Exchanging Access Link Capabilities ........................6
         4.3.1. Network-Initiated Calls .............................7
         4.3.2. User-Initiated Calls ................................7
         4.3.3. Utilizing Call Setup ................................8
 5. Protocol Extensions for Calls and Connections ...................8
    5.1. Call Setup and Teardown ....................................8
    5.2. Call Identification ........................................9
         5.2.1. Long Form Call Identification .......................9
         5.2.2. Short Form Call Identification ......................9
         5.2.3. Short Form Call ID Encoding ........................10
    5.3. LINK_CAPABILITY Object ....................................11
    5.4. Revised Message Formats ...................................12
         5.4.1. Notify Message .....................................12
    5.5. ADMIN_STATUS Object .......................................13
 6. Procedures in Support of Calls and Connections .................14
    6.1. Call/Connection Setup Procedures ..........................14
    6.2. Call Setup ................................................14
         6.2.1. Accepting Call Setup ...............................16
         6.2.2. Call Setup Failure and Rejection ...................16
    6.3. Adding a Connections to a Call ............................17
         6.3.1. Adding a Reverse Direction LSP to a Call ...........18
    6.4. Call-Free Connection Setup ................................18
    6.5. Call Collision ............................................18
    6.6. Call/Connection Teardown ..................................19
         6.6.1. Removal of a Connection from a Call ................20
         6.6.2. Removal of the Last Connection from a Call .........20
         6.6.3. Teardown of an "Empty" Call ........................20
         6.6.4. Attempted Teardown of a Call with Existing
                Connections ........................................20
         6.6.5. Teardown of a Call from the Egress .................21
    6.7. Control Plane Survivability ...............................21
 7. Applicability of Call and Connection Procedures ................22
    7.1. Network-Initiated Calls ...................................22
    7.2. User-Initiated Calls ......................................23
    7.3. External Call Managers ....................................23
         7.3.1. Call Segments ......................................23

Papadimitriou & Farrel Standards Track [Page 2] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

 8. Non-Support of Call ID .........................................24
    8.1. Non-Support by External Call Managers .....................24
    8.2. Non-Support by Transit Node ...............................24
    8.3. Non-Support by Egress Node ................................25
 9. Security Considerations ........................................25
    9.1. Call and Connection Security Considerations ...............25
 10. IANA Considerations ...........................................26
    10.1. RSVP Objects .............................................26
    10.2. RSVP Error Codes and Error Values ........................27
    10.3. RSVP ADMIN_STATUS Object Bits ............................27
 11. Acknowledgements ..............................................27
 12. References ....................................................28
    12.1. Normative References .....................................28
    12.2. Informative References ...................................29

1. Introduction

 This document defines protocol procedures and extensions to support
 Calls within Generalized MPLS (GMPLS).
 A Call is an association between endpoints and possibly between key
 transit points (such as network boundaries) in support of an instance
 of a service.  The end-to-end association is termed a "Call", and the
 association between two transit points or between an endpoint and a
 transit point is termed a "Call Segment".  An entity that processes a
 Call or Call Segment is called a "Call Manager".
 A Call does not provide the actual connectivity for transmitting user
 traffic, but only builds a relationship by which subsequent
 Connections may be made.  In GMPLS, such Connections are known as
 Label Switched Paths (LSPs).  This document does not modify
 Connection setup procedures defined in [RFC3473], [RFC4208], and
 [STITCH].  Connections set up as part of a Call follow the rules
 defined in these documents.
 A Call may be associated with zero, one, or more than one Connection,
 and a Connection may be associated with zero or one Call.  Thus, full
 and logical Call/Connection separation is needed.
 An example of the requirements for Calls can be found in the ITU-T's
 Automatically Switched Optical Network (ASON) architecture [G.8080]
 and specific requirements for support of Calls in this context can be
 found in [RFC4139].  Note, however, that while the mechanisms
 described in this document meet the requirements stated in [RFC4139],
 they have wider applicability.

Papadimitriou & Farrel Standards Track [Page 3] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

 The mechanisms defined in this document are equally applicable to any
 packet (PSC) interface, layer-2 interfaces (L2SC), TDM capable
 interfaces, LSC interfaces, or FSC interfaces.  The mechanisms and
 protocol extensions are backward compatible, and can be used for Call
 management where only the Call Managers need to be aware of the
 protocol extensions.

1.1. Applicability to ASON

 [RFC4139] details the requirements on GMPLS signaling to satisfy the
 ASON architecture described in [G.8080].  The mechanisms described in
 this document meet the requirements for Calls as described in
 Sections 4.2 and 4.3 of [RFC4139] and the additional Call-related
 requirements in Sections 4.4, 4.7, 5, and 6 of [RFC4139].
 [ASON-APPL] describes the applicability of GMPLS protocols to the
 ASON architecture.

2. Conventions Used in This document

 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
 "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and "OPTIONAL" in this
 document are to be interpreted as described in [RFC2119].
 In addition, the reader is assumed to be familiar with the
 terminology used in [RFC3471], [RFC3473], [RFC3477], and [RFC3945].

3. Requirements

3.1. Basic Call Function

 The Call concept is used to deliver the following capabilities:
  1. Verification and identification of the Call initiator (prior to

LSP setup).

  1. Support of virtual concatenation with diverse path component LSPs.
  1. Association of multiple LSPs with a single Call (note aspects

related to recovery are detailed in [RFC4426] and [GMPLS-E2E]).

  1. Facilitation of control plane operations by allowing an

operational status change of the associated LSP.

 Procedures and protocol extensions to support Call setup, and the
 association of Calls with Connections are described in Section 5 and
 onwards of this document.

Papadimitriou & Farrel Standards Track [Page 4] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

3.2. Call/Connection Separation

 Full and logical Call and Connection separation is required.  That
 is:
  1. It MUST be possible to establish a Connection without dependence

on a Call.

  1. It MUST be possible to establish a Call without any associated

Connections.

  1. It MUST be possible to associate more than one Connection with a

Call.

  1. Removal of the last Connection associated with a Call SHOULD NOT

result in the automatic removal of the Call except as a matter of

    local policy at the ingress of the Call.
  1. Signaling of a Connection associated with a Call MUST NOT require

the distribution or retention of Call-related information (state)

    within the network.

3.3. Call Segments

 Call Segment capabilities MUST be supported.
 Procedures and (GMPLS) RSVP-TE signaling protocol extensions to
 support Call Segments are described in Section 7.3.1 of this
 document.

4. Concepts and Terms

 The concept of a Call and a Connection are also discussed in the ASON
 architecture [G.8080] and [RFC4139].  This section is not intended as
 a substitute for those documents, but is a brief summary of the key
 terms and concepts.

4.1. What Is a Call?

 A Call is an agreement between endpoints possibly in cooperation with
 the nodes that provide access to the network.  Call setup may include
 capability exchange, policy, authorization, and security.
 A Call is used to facilitate and manage a set of Connections that
 provide end-to-end data services.  While Connections require state to
 be maintained at nodes along the data path within the network, Calls
 do not involve the participation of transit nodes except to forward
 the Call management requests as transparent messages.

Papadimitriou & Farrel Standards Track [Page 5] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

 A Call may be established and maintained independently of the
 Connections that it supports.

4.2. A Hierarchy of Calls, Connections, Tunnels, and LSPs

 Clearly, there is a hierarchical relationship between Calls and
 Connections.  One or more Connections may be associated with a Call.
 A Connection may not be part of more than one Call.  A Connection
 may, however, exist without a Call.
 In GMPLS RSVP-TE [RFC3473], a Connection is identified with a GMPLS
 TE Tunnel.  Commonly, a Tunnel is identified with a single LSP, but
 it should be noted that for protection, load balancing, and many
 other functions, a Tunnel may be supported by multiple parallel LSPs.
 The following identification reproduces this hierarchy.
  1. Call IDs are unique within the context of the pair of addresses

that are the source and destination of the Call.

  1. Tunnel IDs are unique within the context of the Session (that is

the destination of the Tunnel). Applications may also find it

    convenient to keep the Tunnel ID unique within the context of a
    Call.
  1. LSP IDs are unique within the context of a Tunnel.
 Note that the Call_ID value of zero is reserved and MUST NOT be used
 during LSP-independent Call establishment.
 Throughout the remainder of this document, the terms LSP and Tunnel
 are used interchangeably with the term Connection.  The case of a
 Tunnel that is supported by more than one LSP is covered implicitly.

4.3. Exchanging Access Link Capabilities

 In an overlay model, it is useful for the ingress node of an LSP to
 know the link capabilities of the link between the network and the
 remote overlay network.  In the language of [RFC4208], the ingress
 node can make use of information about the link between the egress
 core node (CN) and the remote edge node (EN).  We call this link the
 egress network link.  This information may allow the ingress node to
 tailor its LSP request to fit those capabilities and to better
 utilize network resources with regard to those capabilities.
 For example, this might be used in transparent optical networks to
 supply information on lambda availability on egress network links,
 or, where the egress CN is capable of signal regeneration, it might
 provide a mechanism for negotiating signal quality attributes (such

Papadimitriou & Farrel Standards Track [Page 6] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

 as bit error rate).  Similarly, in multi-domain routing environments,
 it could be used to provide end-to-end selection of component links
 (i.e., spatial attribute negotiation) where TE links have been
 bundled based on technology specific attributes.
 In some circumstances, the Traffic Engineering Database (TED) may
 contain sufficient information for decisions to be made about which
 egress network link to use.  In other circumstances, the TED might
 not contain this information and Call setup may provide a suitable
 mechanism to exchange information for this purpose.  The Call-
 responder may use the Call parameters to select a subset of the
 available egress network links between the egress CN and the remote
 EN, and may report these links and their capabilities on the Call
 response so that the Call-initiator may select a suitable link.
 The sections that follow indicate the cases where the TED may be
 used, and those where Call parameter exchange may be appropriate.

4.3.1. Network-Initiated Calls

 Network-initiated Calls arise when the ingress (and correspondingly
 the egress) lie within the network and there may be no need to
 distribute additional link capability information over and above the
 information distributed by the TE and GMPLS extensions to the IGP.
 Further, it is possible that future extensions to these IGPs will
 allow the distribution of more detailed information including optical
 impairments.

4.3.2. User-Initiated Calls

 User-initiated Calls arise when the ingress (and correspondingly the
 egress) lie outside the network.  Edge link information may not be
 visible within the core network, nor (and specifically) at other edge
 nodes.  This may prevent an ingress from requesting suitable LSP
 characteristics to ensure successful LSP setup.
 Various solutions to this problem exist, including the definition of
 static TE links (that is, not advertised by a routing protocol)
 between the CNs and ENs.  Nevertheless, special procedures may be
 necessary to advertise to the edge nodes outside of the network
 information about egress network links without also advertising the
 information specific to the contents of the network.
 In the future, when the requirements on the information that needs to
 be supported are better understood, TE extensions to EGPs may be
 defined to provide this function, and new rules for leaking TE
 information between routing instances may be used.

Papadimitriou & Farrel Standards Track [Page 7] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

4.3.3. Utilizing Call Setup

 When IGP and EGP solutions are not available at the User-to-Network
 Interface (UNI), there is still a requirement to have the knowledge
 of the remote edge link capabilities at the local edge nodes.
 The Call setup procedure provides an opportunity to discover edge
 link capabilities of remote edge nodes before LSP setup is attempted.
  1. The Call-responder can return information on one or more egress

network links. The Call-responder could return a full list of the

    available links with information about the link capabilities, or
    it could filter the list to return information about only those
    links that might be appropriate to support the Connections needed
    by the Call.  To do this second option, the Call-responder must
    determine such appropriate links from information carried in the
    Call request including destination of the Call, and the level of
    service (bandwidth, protection, etc.) required.
  1. On receiving a Call response, the Call-initiator must determine

paths for the Connections (LSPs) that it will set up. The way

    that it does this is out of scope for this document since it is an
    implementation-specific, algorithmic process.  However, it can
    take as input the information about the available egress network
    links as supplied in the Call response.
 The LINK_CAPABILITY object is defined to allow this information to be
 exchanged.  The information that is included in this object is
 similar to that distributed by GMPLS-capable IGPs (see [RFC4202]).

5. Protocol Extensions for Calls and Connections

 This section describes the protocol extensions needed in support of
 Call identification and management of Calls and Connections.
 Procedures for the use of these protocol extensions are described in
 Section 6.

5.1. Call Setup and Teardown

 Calls are established independently of Connections through the use of
 the Notify message.  The Notify message is a targeted message and
 does not need to follow the path of LSPs through the network.
 Simultaneous Call and Connection establishment (sometimes referred to
 as piggybacking) is not supported.

Papadimitriou & Farrel Standards Track [Page 8] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

5.2. Call Identification

 As soon as the concept of a Call is introduced, it is necessary to
 support some means of identifying the Call.  This becomes
 particularly important when Calls and Connections are separated and
 Connections must contain some reference to the Call.
 A Call may be identified by a sequence of bytes that may have
 considerable (but not arbitrary) length.  A Call ID of 40 bytes would
 not be unreasonable.  It is not the place of this document to supply
 rules for encoding or parsing Call IDs, but it must provide a
 suitable means to communicate Call IDs within the protocol.  The full
 Call identification is referred to as the long Call ID.
 The Call_ID is only relevant at the sender and receiver nodes.
 Maintenance of this information in the signaling state is not
 mandated at any intermediate node.  Thus, no change in [RFC3473]
 transit implementations is required and there are no backward
 compatibility issues.  Forward compatibility is maintained by using
 the existing default values to indicate that no Call processing is
 required.
 Further, the long Call ID is not required as part of the Connection
 (LSP) state even at the sender and receiver nodes so long as some
 form of correlation is available.  This correlation is provided
 through the short Call ID.

5.2.1. Long Form Call Identification

 The long Call ID is only required on the Notify message used to
 establish the Call.  It is carried in the "Session Name" field of the
 SESSION_ATTRIBUTE object on the Notify message.
 A unique value per Call is inserted in the "Session Name" field by
 the initiator of the Call.  Subsequent core nodes MAY inspect this
 object and MUST forward this object transparently across network
 interfaces until reaching the egress node.  Note that the structure
 of this field MAY be the object of further formatting depending on
 the naming convention(s).  However, [RFC3209] defines the "Session
 Name" field as a Null padded display string, so any formatting
 conventions for the Call ID must be limited to this scope.

5.2.2. Short Form Call Identification

 The Connections (LSPs) associated with a Call need to carry a
 reference to the Call - the short Call ID.  A new field is added to
 the signaling protocol to identify an individual LSP with the Call to
 which it belongs.

Papadimitriou & Farrel Standards Track [Page 9] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

 The new field is a 16-bit identifier (unique within the context of
 the address pairing provided by the Tunnel_End_Point_Address and the
 Sender_Address of the SENDER_TEMPLATE object) that MUST be exchanged
 on the Notify message during Call initialization and is used on all
 subsequent LSP messages that are associated with the Call.  This
 identifier is known as the short Call ID and is encoded as described
 in Section 5.2.3.  The Call ID MUST NOT be used as part of the
 processing to determine the session to which an RSVP signaling
 message applies.  This does not generate any backward compatibility
 issue since the reserved field of the SESSION object defined in
 [RFC3209] MUST NOT be examined on receipt.
 In the unlikely case of short Call_ID exhaustion, local node policy
 decides upon specific actions to be taken, but might include the use
 of second Sender_Address.  Local policy details are outside of the
 scope of this document.

5.2.3. Short Form Call ID Encoding

 The short Call ID is carried in a 16-bit field in the SESSION object
 carried on the Notify message used during Call setup, and on all
 messages during LSP setup and management.  The field used was
 previously reserved (MUST be set to zero on transmission and ignored
 on receipt).  This ensures backward compatibility with nodes that do
 not utilize Calls.
 The figure below shows the new version of the object.
 Class = SESSION, Class-Num = 1, C-Type = 7(IPv4)/8(IPv6)
     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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    ~               IPv4/IPv6 Tunnel End Point Address              ~
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |            Call_ID            |           Tunnel ID           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                       Extended Tunnel ID                      |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 IPv4/IPv6 Tunnel End Point Address: 32 bits/128 bits (see [RFC3209])
 Call_ID: 16 bits
    A 16-bit identifier used in the SESSION object that remains
    constant over the life of the Call.  The Call_ID value MUST be set
    to zero when there is no corresponding Call.

Papadimitriou & Farrel Standards Track [Page 10] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

 Tunnel ID: 16 bits (see [RFC3209])
 Extended Tunnel ID: 32 bits/128 bits (see [RFC3209])

5.3. LINK_CAPABILITY Object

 The LINK_CAPABILITY object is introduced to support link capability
 exchange during Call setup and MAY be included in a Notify message
 used for Call setup.  This optional object includes the link-local
 capabilities of a link joining the Call-initiating node (or Call-
 terminating node) to the network.  The specific node is indicated by
 the source address of the Notify message.
 The link reported can be a single link or can be a bundled link
 [RFC4201].
 The Class Number is selected so that the nodes that do not recognize
 this object drop it silently.  That is, the top bit is set and the
 next bit is clear.
 This object has the following format:
 Class-Num = 133 (form 10bbbbbb), C_Type = 1
     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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                                                               |
    //                        (Subobjects)                         //
    |                                                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 The contents of the LINK_CAPABILITY object is defined as a series of
 variable-length data items called subobjects.  The subobject format
 is defined in [RFC3209].
 The following subobjects are currently defined.
  1. Type 1: the link local IPv4 address of a link or a numbered bundle

using the format defined in [RFC3209].

  1. Type 2: the link local IPv6 address of a link or a numbered bundle

using the format defined in [RFC3209].

  1. Type 4: the link local identifier of an unnumbered link or bundle

using the format defined in [RFC3477].

Papadimitriou & Farrel Standards Track [Page 11] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

  1. Type 64: the Maximum Reservable Bandwidth corresponding to this

link or bundle (see [RFC4201]).

  1. Type 65: the interface switching capability descriptor (see

[RFC4202]) corresponding to this link or bundle (see also

    [RFC4201]).
 Note: future revisions of this document may extend the above list.
 A single instance of this object MAY be used to exchange capability
 information relating to more than one link or bundled link.  In this
 case, the following ordering MUST be used:
  1. each link MUST be identified by an identifier subobject (Type 1,

2, or 4)

  1. capability subobjects (Type 64 or 65, and future subobjects) MUST

be placed after the identifier subobject for the link or bundle to

    which they refer.
 Multiple instances of the LINK_CAPABILITY object within the same
 Notify message are not supported by this specification.  In the event
 that a Notify message contains multiple LINK_CAPABILITY objects, the
 receiver SHOULD process the first one as normal and SHOULD ignore
 subsequent instances of the object.

5.4. Revised Message Formats

 The Notify message is enhanced to support Call establishment and
 teardown of Calls.  See Section 6 for a description of the
 procedures.

5.4.1. Notify Message

 The Notify message is modified in support of Call establishment by
 the optional addition of the LINK_CAPABILITY object.  Further, the
 SESSION_ATTRIBUTE object is added to the <notify session> sequence to
 carry the long Call ID.  The presence of the SESSION_ATTRIBUTE object
 MAY be used to distinguish a Notify message used for Call management,
 but see Section 5.5 for another mechanism.  The <notify session list>
 MAY be used to simultaneously set up multiple Calls.

Papadimitriou & Farrel Standards Track [Page 12] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

 The format of the Notify Message is as follows:
 <Notify message>  ::= <Common Header> [ <INTEGRITY> ]
                       [[ <MESSAGE_ID_ACK> | <MESSAGE_ID_NACK>]...]
                       [ <MESSAGE_ID> ]
                       <ERROR_SPEC>
                       <notify session list>
 <notify session list> ::= [ <notify session list> ] <notify session>
 <notify session>  ::= <SESSION> [ <ADMIN_STATUS> ]
                       [ <POLICY_DATA>...]
                       [ <LINK_CAPABILITY> ]
                       [ <SESSION_ATTRIBUTE> ]
                       [ <sender descriptor> | <flow descriptor> ]
 <sender descriptor> ::= see [RFC3473]
 <flow descriptor> ::= see [RFC3473]

5.5. ADMIN_STATUS Object

 Notify messages exchanged for Call control and management purposes
 carry a specific new bit (the Call Management or C bit) in the
 ADMIN_STATUS object.
 [RFC3473] indicates that the format and contents of the ADMIN_STATUS
 object are as defined in [RFC3471].  The new "C" bit is added for
 Call control as shown below.
     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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |R|                        Reserved                     |C|T|A|D|
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       Reflect (R): 1 bit - see [RFC3471]
       Testing (T): 1 bit - see [RFC3471]
       Administratively down (A): 1 bit - see [RFC3471]
       Deletion in progress (D): 1 bit - see [RFC3471]
       Call Management (C): 1 bit
          This bit is set when the message is being used to control
          and manage a Call.
 The procedures for the use of the C bit are described in Section 6.

Papadimitriou & Farrel Standards Track [Page 13] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

6. Procedures in Support of Calls and Connections

6.1. Call/Connection Setup Procedures

 This section describes the processing steps for Call and Connection
 setup.
 There are three cases considered:
  1. A Call is set up without any associated Connection. It is assumed

that Connections will be added to the Call at a later time, but

    this is neither a requirement nor a constraint.
  1. A Connection may be added to an existing Call. This may happen if

the Call was set up without any associated Connections, or if

    another Connection is added to a Call that already has one or more
    associated Connections.
  1. A Connection may be established without any reference to a Call

(see Section 6.4). This encompasses the previous LSP setup

    procedure.
 Note that a Call MUST NOT be imposed upon a Connection that is
 already established.  To do so would require changing the short Call
 ID in the SESSION object of the existing LSPs and this would
 constitute a change in the Session Identifier.  This is not allowed
 by existing protocol specifications.
 Call and Connection teardown procedures are described later in
 Section 6.6.

6.2. Call Setup

 A Call is set up before, and independent of, LSP (i.e., Connection)
 setup.
 Call setup MAY necessitate verification of the link status and link
 capability negotiation between the Call ingress node and the Call
 egress node.  The procedure described below is applied only once for
 a Call and hence only once for the set of LSPs associated with a
 Call.
 The Notify message (see [RFC3473]) is used to signal the Call setup
 request and response.  The new Call Management (C) bit in the
 ADMIN_STATUS object is used to indicate that this Notify is managing
 a Call.  The Notify message is sent with source and destination
 IPv4/IPv6 addresses set to any of the routable ingress/egress node
 addresses respectively.

Papadimitriou & Farrel Standards Track [Page 14] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

 At least one session MUST be listed in the <notify session list> of
 the Notify message.  In order to allow for long identification of the
 Call, the SESSION_ATTRIBUTE object is added as part of the <notify
 session list>.  Note that the ERROR_SPEC object is not relevant in
 Call setup and MUST carry the Error Code zero ("Confirmation") to
 indicate that there is no error.
 During Call setup, the ADMIN_STATUS object is sent with the following
 bits set.  Bits not listed MUST be set to zero.
 R - to cause the egress to respond
 C - to indicate that the Notify message is managing a Call.
 The SESSION, SESSION_ATTRIBUTE, SENDER_TEMPLATE, SENDER_TSPEC objects
 included in the <notify session> of the Notify message are built as
 follows.
  1. The SESSION object includes as Tunnel_End_Point_Address any of the

Call-terminating (egress) node's IPv4/IPv6 routable addresses.

    The Call_ID is set to a non-zero value unique within the context
    of the address pairing provided by the Tunnel_End_Point_Address
    and the Sender_Address from the SENDER_TEMPLATE object (see
    below).  This value will be used as the short Call ID carried on
    all messages for LSPs associated with this Call.
    Note that the Call_ID value of zero is reserved and MUST NOT be
    used since it will be present in SESSION objects of LSPs that are
    not associated with Calls.  The Tunnel_ID of the SESSION object is
    not relevant for this procedure and SHOULD be set to zero.  The
    Extended_Tunnel_ID of the SESSION object is not relevant for this
    procedure and MAY be set to zero or to an address of the ingress
    node.
  1. The SESSION_ATTRIBUTE object contains priority flags. Currently

no use of these flags is envisioned, however, future work may

    identify value in assigning priorities to Calls; accordingly the
    Priority fields MAY be set to non-zero values.  None of the Flags
    in the SESSION_ATTRIBUTE object is relevant to this process and
    this field SHOULD be set to zero.  The Session Name field is used
    to carry the long Call Id as described in Section 5.
  1. The SENDER_TEMPLATE object includes as Sender Address any of the

Call-initiating (ingress) node's IPv4/IPv6 routable addresses.

    The LSP_ID is not relevant and SHOULD be set to zero.
  1. The bandwidth value inserted in the SENDER_TSPEC and FLOWSPEC

objects MUST be ignored upon receipt and SHOULD be set to zero

    when sent.

Papadimitriou & Farrel Standards Track [Page 15] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

 Additionally, ingress/egress nodes that need to communicate their
 respective link local capabilities may include a LINK_CAPABILITY
 object in the Notify message.
 The receiver of a Notify message may identify whether it is part of
 Call management or reporting an error by the presence or absence of
 the SESSION_ATTRIBUTE object in the <notify session list>.  Full
 clarity, however, may be achieved by inspection of the new Call
 Management (C) bit in the ADMIN_STATUS object.
 Note that the POLICY_DATA object may be included in the <notify
 session list> and MAY be used to identify requestor credentials,
 account numbers, limits, quotas, etc.  This object is opaque to RSVP,
 which simply passes it to policy control when required.
 Message IDs MUST be used during Call setup.

6.2.1. Accepting Call Setup

 A node that receives a Notify message carrying the ADMIN_STATUS
 object with the R and C bits set is being requested to set up a Call.
 The receiver MAY perform authorization and policy according to local
 requirements.
 If the Call is acceptable, the receiver responds with a Notify
 message reflecting the information from the Call request with two
 exceptions.
  1. The responder removes any LINK_CAPABLITY object that was received

and MAY insert a LINK_CAPABILITY object that describes its own

    access link.
  1. The ADMIN_STATUS object is sent with only the C bit set. All

other bits MUST be set to zero.

 The responder MUST use the Message ID object to ensure reliable
 delivery of the response.  If no Message ID Acknowledgement is
 received after the configured number of retries, the responder SHOULD
 continue to assume that the Call was successfully established.  Call
 liveliness procedures are covered in Section 6.7.

6.2.2. Call Setup Failure and Rejection

 Call setup may fail or be rejected.
 If the Notify message can not be delivered, no Message ID
 acknowledgement will be received by the sender.  In the event that
 the sender has retransmitted the Notify message a configurable number

Papadimitriou & Farrel Standards Track [Page 16] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

 of times without receiving a Message ID Acknowledgement (as described
 in [RFC2961]), the initiator SHOULD declare the Call failed and
 SHOULD send a Call teardown request (see Section 6.6).
 It is also possible that a Message ID Acknowledgement is received but
 no Call response Notify message is received.  In this case, the
 initiator MAY re-send the Call setup request a configurable number of
 times (see Section 6.7) before declaring that the Call has failed.
 At this point, the initiator MUST send a Call teardown request (see
 Section 6.6).
 If the Notify message cannot be parsed or is in error, it MAY be
 responded to with a Notify message carrying the error code 13
 ("Unknown object class") or 14 ("Unknown object C-Type") if
 appropriate to the error detected.
 The Call setup MAY be rejected by the receiver because of security,
 authorization, or policy reasons.  Suitable error codes already exist
 [RFC2205] and can be used in the ERROR_SPEC object included in the
 Notify message sent in response.
 Error response Notify messages SHOULD also use the Message ID object
 to achieve reliable delivery.  No action should be taken on the
 failure to receive a Message ID Acknowledgement after the configured
 number of retries.

6.3. Adding a Connections to a Call

 Once a Call has been established, LSPs can be added to the Call.
 Since the short Call ID is part of the SESSION object, any LSP that
 has the same Call ID value in the SESSION object belongs to the same
 Call, and the Notify message used to establish the Call carried the
 same Call ID in its SESSION object.
 There will be no confusion between LSPs that are associated with a
 Call and those which are not, since the Call ID value MUST be equal
 to zero for LSPs that are not associated with a Call, and MUST NOT be
 equal to zero for a valid Call ID.
 LSPs for different Calls can be distinguished because the Call ID is
 unique within the context of the source address (in the
 SENDER_TEMPLATE object) and the destination address (in the SESSION
 object).
 Ingress and egress nodes MAY group together LSPs associated with the
 same Call and process them as a group according to implementation
 requirements.  Transit nodes need not be aware of the association of
 multiple LSPs with the same Call.

Papadimitriou & Farrel Standards Track [Page 17] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

 The ingress node MAY choose to set the "Session Name" of an LSP to
 match the long Call ID of the associated Call.
 The C bit of the ADMIN_STATUS object MUST NOT be set on LSP messages
 including on Notify messages that pertain to the LSP and MUST be
 ignored.

6.3.1. Adding a Reverse Direction LSP to a Call

 Note that once a Call has been established, it is symmetric.  That
 is, either end of the Call may add LSPs to the Call.
 Special care is needed when managing LSPs in the reverse direction
 since the addresses in the SESSION and SENDER_TEMPLATE are reversed.
 However, since the short Call ID is unique in the context of a given
 ingress-egress address pair, it may safely be used to associate the
 LSP with the Call.
 Note that since Calls are defined here to be symmetrical, the issue
 of potential Call ID collision arises.  This is discussed in Section
 6.5.

6.4. Call-Free Connection Setup

 It continues to be possible to set up LSPs as per [RFC3473] without
 associating them with a Call.  If the short Call ID in the SESSION
 object is set to zero, there is no associated Call and the Session
 Name field in the SESSION_ATTRIBUTE object MUST be interpreted simply
 as the name of the session (see [RFC3209]).
 The C bit of the ADMIN_STATUS object MUST NOT be set on messages for
 LSP control, including on Notify messages that pertain to LSPs, and
 MUST be ignored when received on such messages.

6.5. Call Collision

 Since Calls are symmetrical, it is possible that both ends of a Call
 will attempt to establish Calls with the same long Call IDs at the
 same time.  This is only an issue if the source and destination
 address pairs match.  This situation can be avoided by applying some
 rules to the contents of the long Call ID, but such mechanisms are
 outside the scope of this document.
 If a node that has sent a Call setup request and has not yet received
 a response itself receives a Call setup request with the same long
 Call ID and matching source/destination addresses, it SHOULD process
 as follows:

Papadimitriou & Farrel Standards Track [Page 18] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

  1. If its source address is numerically greater than the remote

source address, it MUST discard the received message and continue

    to wait for a response to its setup request.
  1. If its source address is numerically smaller than the remote

source address, it MUST discard state associated with the Call

    setup that it initiated, and MUST respond to the received Call
    setup.
 If a node receives a Call setup request carrying an address pair and
 long Call ID that match an existing Call, the node MUST return an
 error message (Notify message) with the new Error Code "Call
 Management" and the new Error Value "Duplicate Call" in response to
 the new Call request, and MUST NOT make any changes to the existing
 Call.
 A further possibility for contention arises when short Call IDs are
 assigned by a pair of nodes for two distinct Calls that are set up
 simultaneously using different long Call IDs.  In this event, a node
 receives a Call setup request carrying a short Call ID that matches
 one that it previously sent for the same address pair.  The following
 processing MUST be followed:
  1. If the receiver's source address is numerically greater than the

remote source address, the receiver returns an error (Notify

    message) with the new Error Code "Call Management" and the new
    Error Value "Call ID Contention".
  1. If the receiver's source address is numerically less than the

remote source address, the receiver accepts and processes the Call

    request.  It will receive an error message sent as described
    above, and at that point, it selects a new short Call ID and re-
    sends the Call setup request.

6.6. Call/Connection Teardown

 As with Call/Connection setup, there are several cases to consider.
  1. Removal of a Connection from a Call
  2. Removal of the last Connection from a Call
  3. Teardown of an "empty" Call
 The case of tearing down an LSP that is not associated with a Call
 does not need to be examined as it follows exactly the procedures
 described in [RFC3473].

Papadimitriou & Farrel Standards Track [Page 19] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

6.6.1. Removal of a Connection from a Call

 An LSP that is associated with a Call may be deleted using the
 standard procedures described in [RFC3473].  No special procedures
 are required.
 Note that it is not possible to remove an LSP from a Call without
 deleting the LSP.  It is not valid to change the short Call ID from
 non-zero to zero since this involves a change to the SESSION object,
 which is not allowed.

6.6.2. Removal of the Last Connection from a Call

 When the last LSP associated with a Call is deleted, the question
 arises as to what happens to the Call.  Since a Call may exist
 independently of Connections, it is not always acceptable to say that
 the removal of the last LSP from a Call removes the Call.
 The removal of the last LSP does not remove the Call and the
 procedures described in the next Section MUST be used to delete the
 Call.

6.6.3. Teardown of an "Empty" Call

 When all LSPs have been removed from a Call, the Call may be torn
 down or left for use by future LSPs.
 Deletion of Calls is achieved by sending a Notify message just as for
 Call setup, but the ADMIN_STATUS object carries the R, D, and C bits
 on the teardown request and the D and C bits on the teardown
 response.  Other bits MUST be set to zero.
 When a Notify message is sent for deleting a Call and the initiator
 does not receive the corresponding reflected Notify message (or
 possibly even the Message ID Ack), the initiator MAY retry the
 deletion request using the same retry procedures as used during Call
 establishment.  If no response is received after full retry, the node
 deleting the Call MAY declare the Call deleted, but under such
 circumstances the node SHOULD avoid re-using the long or short Call
 IDs for at least five times the Notify refresh period.

6.6.4. Attempted Teardown of a Call with Existing Connections

 If a Notify request with the D bit of the ADMIN_STATUS object set is
 received for a Call for which LSPs still exist, the request MUST be
 rejected with the Error Code "Call Management" and Error Value
 "Connections Still Exist".  The state of the Call MUST NOT be
 changed.

Papadimitriou & Farrel Standards Track [Page 20] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

6.6.5. Teardown of a Call from the Egress

 Since Calls are symmetric, they may be torn down from the ingress or
 egress.
 When the Call is "empty" (has no associated LSPs), it may be deleted
 by the egress sending a Notify message just as described above.
 Note that there is a possibility that both ends of a Call initiate
 Call deletion at the same time.  In this case, the Notify message
 acting as teardown request MAY be interpreted by its recipient as a
 teardown response.  But since the Notify messages acting as teardown
 requests carry the R bit in the ADMIN_STATUS object, they MUST be
 responded to anyway.  If a teardown request Notify message is
 received for an unknown Call ID, it is, nevertheless, responded to in
 the affirmative.

6.7. Control Plane Survivability

 Delivery of Notify messages is secured using Message ID
 Acknowledgements as described in previous sections.
 Notify messages provide end-to-end communication that does not rely
 on constant paths through the network.  Notify messages are routed
 according to IGP routing information.  No consideration is,
 therefore, required for network resilience (for example, make-
 before-break, protection, fast re-route), although end-to-end
 resilience is of interest for node restart and completely disjoint
 networks.
 Periodic Notify messages SHOULD be sent by the initiator and
 terminator of the Call to keep the Call alive and to handle ingress
 or egress node restart.  The time period for these retransmissions is
 a local matter, but it is RECOMMENDED that this period should be
 twice the shortest refresh period of any LSP associated with the
 Call.  When there are no LSPs associated with a Call, an LSR is
 RECOMMENDED to use a refresh period of no less than one minute.  The
 Notify messages are identical to those sent as if establishing the
 Call for the first time, except for the LINK_CAPABILITY object, which
 may have changed since the Call was first established, due to, e.g.,
 the establishment of Connections, link failures, or the addition of
 new component links.  The current link information is useful for the
 establishment of subsequent Connections.  A node that receives a
 refresh Notify message carrying the R bit in the ADMIN_STATUS object
 MUST respond with a Notify response.  A node that receives a refresh
 Notify message (response or request) MAY reset its timer - thus, in
 normal processing, Notify refreshes involve a single exchange once
 per time period.

Papadimitriou & Farrel Standards Track [Page 21] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

 A node (sender or receiver) that is unsure of the status of a Call
 MAY immediately send a Notify message as if establishing the Call for
 the first time.
 Failure to receive a refresh Notify request has no specific meaning.
 A node that fails to receive a refresh Notify request MAY send its
 own refresh Notify request to establish the status of the Call.  If a
 node receives no response to a refresh Notify request (including no
 Message ID Acknowledgement), a node MAY assume that the remote node
 is unreachable or unavailable.  It is a local policy matter whether
 this causes the local node to teardown associated LSPs and delete the
 Call.
 In the event that an edge node restarts without preserved state, it
 MAY relearn LSP state from adjacent nodes and Call state from remote
 nodes.  If a Path or Resv message is received with a non-zero Call ID
 but without the C bit in the ADMIN_STATUS, and for a Call ID that is
 not recognized, the receiver is RECOMMENDED to assume that the Call
 establishment is delayed and ignore the received message.  If the
 Call setup never materializes, the failure by the restarting node to
 refresh state will cause the LSPs to be torn down.  Optionally, the
 receiver of such an LSP message for an unknown Call ID may return an
 error (PathErr or ResvErr message) with the error code "Call
 Management" and Error Value "Unknown Call ID".

7. Applicability of Call and Connection Procedures

 This section considers the applicability of the different Call
 establishment procedures at the NNI and UNI reference points.  This
 section is informative and is not intended to prescribe or prevent
 other options.

7.1. Network-Initiated Calls

 Since the link properties and other traffic-engineering attributes
 are likely known through the IGP, the LINK_CAPABILITY object is not
 usually required.
 In multi-domain networks, it is possible that access link properties
 and other traffic-engineering attributes are not known since the
 domains do not share this sort of information.  In this case, the
 Call setup mechanism may include the LINK_CAPABILITY object.

Papadimitriou & Farrel Standards Track [Page 22] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

7.2. User-Initiated Calls

 It is possible that the access link properties and other traffic-
 engineering attributes are not shared across the core network.  In
 this case, the Call setup mechanism may include the LINK_CAPABILITY
 object.
 Further, the first node within the network may be responsible for
 managing the Call.  In this case, the Notify message that is used to
 set up the Call is addressed by the user network edge node to the
 first node of the core network.  Moreover, neither the long Call ID
 nor the short Call ID is supplied (the Session Name Length is set to
 zero and the Call ID value is set to zero).  The Notify message is
 passed to the first core node, which is responsible for generating
 the long and short Call IDs before dispatching the message to the
 remote Call end point (which is known from the SESSION object).
 Further, when used in an overlay context, the first core node is
 allowed (see [RFC4208]) to replace the Session Name assigned by the
 ingress node and passed in the Path message.  In the case of Call
 management, the first core node:
    1) MAY insert a long Call ID in the Session Name of a Path
       message.
    2) MUST replace the Session Name with that originally issued by
       the user edge node when it returns the Resv message to the
       ingress node.

7.3. External Call Managers

 Third party Call management agents may be used to apply policy and
 authorization at a point that is neither the initiator nor terminator
 of the Call.  The previous example is a particular case of this, but
 the process and procedures are identical.

7.3.1. Call Segments

 Call Segments exist between a set of default and configured External
 Call Managers along a path between the ingress and egress nodes, and
 use the protocols described in this document.
 The techniques that are used by a given service provider to identify
 which External Call Managers within its network should process a
 given Call are beyond the scope of this document.
 An External Call Manager uses normal IP routing to route the Notify
 message to the next External Call Manager.  Notify messages (requests

Papadimitriou & Farrel Standards Track [Page 23] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

 and responses) are therefore encapsulated in IP packets that identify
 the sending and receiving External Call Managers, but the addresses
 used to identify the Call (the Sender Address in the SENDER_TEMPLATE
 object and the Tunnel Endpoint Address in the SESSION object)
 continue to identify the endpoints of the Call.

8. Non-Support of Call ID

 It is important that the procedures described above operate as
 seamlessly as possible with legacy nodes that do not support the
 extensions described.
 Clearly, there is no need to consider the case where the Call
 initiator does not support Call setup initiation.

8.1. Non-Support by External Call Managers

 It is unlikely that a Call initiator will be configured to send Call
 establishment Notify requests to an external Call manager, including
 the first core node, if that node does not support Call setup.
 A node that receives an unexpected Call setup request will fall into
 one of the following categories.
  1. Node does not support RSVP. The message will fail to be delivered

or responded to. No Message ID Acknowledgement will be sent. The

    initiator will retry and then give up.
  1. Node supports RSVP or RSVP-TE but not GMPLS. The message will be

delivered but not understood. It will be discarded. No Message

    ID Acknowledgement will be sent.  The initiator will retry and
    then give up.
  1. Node supports GMPLS but not Call management. The message will be

delivered, but parsing will fail because of the presence of the

    SESSION_ATTRIBUTE object.  A Message ID Acknowledgement may be
    sent before the parse fails.  When the parse fails, the Notify
    message may be discarded in which case the initiator will retry
    and then give up; alternatively, a parse error may be generated
    and returned in a Notify message which will indicate to the
    initiator that Call management is not supported.

8.2. Non-Support by Transit Node

 Transit nodes SHOULD NOT examine Notify messages that are not
 addressed to them.  However, they will see short Call IDs in all
 messages for all LSPs associated with Calls.

Papadimitriou & Farrel Standards Track [Page 24] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

 Previous specifications state that these fields SHOULD be ignored on
 receipt and MUST be transmitted as zero.  This might be interpreted
 by some implementations as meaning that the fields should be zeroed
 before the objects are forwarded.  If this happens, LSP setup will
 not be possible.  If either of the fields is zeroed either on the
 Path or the Resv message, the Resv message will reach the initiator
 with the field set to zero - this is an indication to the initiator
 that some node in the network is preventing Call management.  Use of
 Explicit Routes may help to mitigate this issue by avoiding such
 nodes.  Ultimately, however, it may be necessary to upgrade the
 offending nodes to handle these protocol extensions.

8.3. Non-Support by Egress Node

 It is unlikely that an attempt will be made to set up a Call to a
 remote node that does not support Calls.
 If the egress node does not support Call management through the
 Notify message, it will react (as described in Section 8.1) in the
 same way as an External Call Manager.

9. Security Considerations

 Please refer to each of the documents referenced in the following
 sections for a description of the security considerations applicable
 to the features that they provide.

9.1. Call and Connection Security Considerations

 Call setup is vulnerable to attacks both of spoofing and denial of
 service.  Since Call setup uses Notify messages, the process can be
 protected by the use of the INTEGRITY object to secure those messages
 as described in [RFC2205] and [RFC3473].  Deployments where security
 is a concern SHOULD use this mechanism.
 Implementations and deployments MAY additionally protect the Call
 setup exchange using end-to-end security mechanisms such as those
 provided by IPsec (see [RFC4302] and [RFC4303]), or using RSVP
 security [RFC2747].
 Note, additionally, that it would be desirable to use the process of
 independent Call establishment, where the Call is set up separately
 from the LSPs, to apply an extra level of authentication and policy
 for the end-to-end LSPs above that which is available with Call-less,
 hop-by-hop LSP setup.  However doing so will require additional work
 to set up security associations between the peer and the call manager
 that meet the requirements of [RFC4107].  The mechanism described in
 this document is expected to meet this use case when combined with

Papadimitriou & Farrel Standards Track [Page 25] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

 this additional work.  Application of this mechanism to the
 authentication and policy use case prior to standardization of a
 security solution is inappropriate and outside the current
 applicability of the mechanism.
 The frequency of Call establishment is application dependent and hard
 to generalize.  Key exchange for Call-related message exchanges is
 therefore something that should be configured or arranged dynamically
 in different deployments according to the advice in [RFC4107].  Note
 that the remote RSVP-TE signaling relationship between Call endpoints
 is no different from the signaling relationship between LSRs that
 establish an LSP.  That is, the LSRs are not necessarily IP-adjacent
 in the control plane in either case.  Thus, key exchange should be
 regarded as a remote procedure, not a single hop procedure.  There
 are several procedures for automatic remote exchange of keys, and
 IKEv2 [RFC4306] is particularly suggested in [RFC3473].

10. IANA Considerations

10.1. RSVP Objects

 A new RSVP object is introduced.  IANA has made an assignment from
 the "RSVP Parameters" registry using the sub-registry "Class Names,
 Class Numbers, and Class Types".
 o  LINK_CAPABILITY object
    Class-Num = 133 (form 10bbbbbb)
    The Class Number is selected so that nodes not recognizing this
    object drop it silently.  That is, the top bit is set and the next
    bit is cleared.
    C-Type = 1 (TE Link Capabilities)
    The LINK_CAPABILITY object is only defined for inclusion on Notify
    messages.
    Refer to Section 5.3 of this document.
    IANA maintains a list of subobjects that may be carried in this
    object.  This list is maintained in the registry entry for the
    LINK_CAPABILITY object as is common practice for the subobjects of
    other RSVP objects.  For each subobject, IANA lists:
  1. subobject type number
  2. subobject name
  3. reference indicating where subobject is defined.

Papadimitriou & Farrel Standards Track [Page 26] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

    The initial list of subobjects is provided in Section 5.3 of this
    document.

10.2. RSVP Error Codes and Error Values

 A new RSVP Error Code and new Error Values are introduced.  IANA has
 made assignments from the "RSVP Parameters" registry using the sub-
 registry "Error Codes and Globally-Defined Error Value Sub-Codes".
 o  Error Codes:
    - Call Management (value 32)
 o  Error Values:
    - Call Management/Call ID Contention      (value 1)
    - Call Management/Connections Still Exist (value 2)
    - Call Management/Unknown Call ID         (value 3)
    - Call Management/Duplicate Call          (value 4)

10.3. RSVP ADMIN_STATUS Object Bits

 [GMPLS-E2E] requested that IANA manage the bits of the RSVP
 ADMIN_STATUS object.  A new "Administrative Status Information Flags"
 sub-registry of the "GMPLS Signaling Parameters" registry was
 created.
 This document defines one new bit, the C bit, to be tracked in that
 sub-registry.  Bit number 28 has been assigned.  See Section 5.5 of
 this document.

11. Acknowledgements

 The authors would like to thank George Swallow, Yakov Rekhter, Lou
 Berger, Jerry Ash, and Kireeti Kompella for their very useful input
 to, and comments on, an earlier revision of this document.
 Thanks to Lyndon Ong and Ben Mack-Crane for lengthy discussions
 during and after working group last call, and to Deborah Brungard for
 a final, detailed review.
 Thanks to Suresh Krishnan for the GenArt review, and to Magnus
 Nystrom for discussions about security.
 Useful comments were received during IESG review from Brian
 Carpenter, Lars Eggert, Ted Hardie, Sam Hartman, and Russ Housley.

Papadimitriou & Farrel Standards Track [Page 27] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

12. References

12.1. Normative References

 [GMPLS-E2E] Lang, J., Ed., Rekhter, Y., Ed., and D. Papadimitriou,
             Ed., "RSVP-TE Extensions in Support of End-to-End
             Generalized Multi-Protocol Label Switching (GMPLS)
             Recovery", RFC 4872, May 2007.
 [RFC2119]   Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, March 1997.
 [RFC2205]   Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and
             S. Jamin, "Resource ReSerVation Protocol (RSVP) --
             Version 1 Functional Specification", RFC 2205, September
             1997.
 [RFC2747]   Baker, F., Lindell, B., and M. Talwar, "RSVP
             Cryptographic Authentication", RFC 2747, January 2000.
 [RFC2961]   Berger, L., Gan, D., Swallow, G., Pan, P., Tommasi, F.,
             and S. Molendini, "RSVP Refresh Overhead Reduction
             Extensions", RFC 2961, April 2001.
 [RFC3209]   Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
             and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
             Tunnels", RFC 3209, December 2001.
 [RFC3471]   Berger, L., Ed., "Generalized Multi-Protocol Label
             Switching (GMPLS) Signaling Functional Description", RFC
             3471, January 2003.
 [RFC3473]   Berger, L., Ed., "Generalized Multi-Protocol Label
             Switching (GMPLS) Signaling Resource ReserVation
             Protocol-Traffic Engineering (RSVP-TE) Extensions", RFC
             3473, January 2003.
 [RFC3477]   Kompella, K. and Y. Rekhter, "Signalling Unnumbered Links
             in Resource ReSerVation Protocol - Traffic Engineering
             (RSVP-TE)", RFC 3477, January 2003.
 [RFC3945]   Mannie, E., Ed., "Generalized Multi-Protocol Label
             Switching (GMPLS) Architecture", RFC 3945, October 2004.
 [RFC4201]   Kompella, K., Rekhter, Y., and L. Berger, "Link Bundling
             in MPLS Traffic Engineering (TE)", RFC 4201, October
             2005.

Papadimitriou & Farrel Standards Track [Page 28] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

 [RFC4202]   Kompella, K., Ed., and Y. Rekhter, Ed., "Routing
             Extensions in Support of Generalized Multi-Protocol Label
             Switching (GMPLS)", RFC 4202, October 2005.
 [RFC4208]   Swallow, G., Drake, J., Ishimatsu, H., and Y. Rekhter,
             "Generalized Multiprotocol Label Switching (GMPLS) User-
             Network Interface (UNI): Resource ReserVation Protocol-
             Traffic Engineering (RSVP-TE) Support for the Overlay
             Model", RFC 4208, October 2005.
 [RFC4302]   Kent, S., "IP Authentication Header", RFC 4302, December
             2005.
 [RFC4303]   Kent, S., "IP Encapsulating Security Payload (ESP)", RFC
             4303, December 2005.
 [RFC4306]   Kaufman, C., Ed., "Internet Key Exchange (IKEv2)
             Protocol", RFC 4306, December 2005.
 [RFC4426]   Lang, J., Ed., Rajagopalan, B., Ed., and D.
             Papadimitriou, Ed., "Generalized Multi-Protocol Label
             Switching (GMPLS) Recovery Functional Specification", RFC
             4426, March 2006.

12.2. Informative References

 [ASON-APPL] Drake, J., Papadimitriou, D., Farrel, A., Brungard, D.,
             Ali, Z., Ayyangar, A., Ould-Brahim, H., and D. Fedyk,
             "Generalized MPLS (GMPLS) RSVP-TE Signalling in support
             of Automatically Switched Optical Network (ASON), Work in
             Progress, July 2005.
 [RFC4107]   Bellovin, S. and R. Housley, "Guidelines for
             Cryptographic Key Management", BCP 107, RFC 4107, June
             2005.
 [RFC4139]   Papadimitriou, D., Drake, J., Ash, J., Farrel, A., and L.
             Ong, "Requirements for Generalized MPLS (GMPLS) Signaling
             Usage and Extensions for Automatically Switched Optical
             Network (ASON)", RFC 4139, July 2005.
 [STITCH]    Ayyangar, A., Kompella, K., Vasseur, JP., and A. Farrel,
             "Label Switched Path Stitching with Generalized
             Multiprotocol Label Switching Traffic Engineering (GMPLS
             TE)", Work in Progress, April 2007.

Papadimitriou & Farrel Standards Track [Page 29] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

 For information on the availability of the following document, please
 see http://www.itu.int.
 [G.8080]      ITU-T, "Architecture for the Automatically Switched
             Optical Network (ASON)," Recommendation G.8080/ Y.1304,
             November 2001 (and Revision, January 2003).

Authors' Addresses

 John Drake
 Boeing Satellite Systems
 2300 East Imperial Highway
 El Segundo, CA 90245
 EMail: John.E.Drake2@boeing.com
 Deborah Brungard (AT&T)
 Rm. D1-3C22 - 200 S. Laurel Ave.
 Middletown, NJ 07748, USA
 EMail: dbrungard@att.com
 Zafar Ali (Cisco)
 100 South Main St. #200
 Ann Arbor, MI 48104, USA
 EMail: zali@cisco.com
 Arthi Ayyangar (Nuova Systems)
 2600 San Tomas Expressway
 Santa Clara, CA 95051
 EMail: arthi@nuovasystems.com
 Don Fedyk (Nortel Networks)
 600 Technology Park Drive
 Billerica, MA, 01821, USA
 EMail: dwfedyk@nortel.com

Contact Addresses

 Dimitri Papadimitriou
 Alcatel-Lucent,
 Fr. Wellesplein 1,
 B-2018 Antwerpen, Belgium
 Phone: +32 3 240-8491
 EMail: dimitri.papadimitriou@alcatel-lucent.be
 Adrian Farrel
 Old Dog Consulting
 Phone: +44 (0) 1978 860944
 EMail: adrian@olddog.co.uk

Papadimitriou & Farrel Standards Track [Page 30] RFC 4974 GMPLS RSVP-TE Signaling Extensions August 2007

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Papadimitriou & Farrel Standards Track [Page 31]

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