GENWiki

Premier IT Outsourcing and Support Services within the UK

User Tools

Site Tools


rfc:rfc2443

Network Working Group J. Luciani Request for Comments: 2443 Bay Networks Category: Experimental A. Gallo

                                                                   IBM
                                                         November 1998
               A Distributed MARS Service Using SCSP

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 Internet Society (1998).  All Rights Reserved.

Abstract

 This document describes a method for distributing a MARS service
 within a LIS[1].  This method uses the Server Cache Synchronization
 Protocol (SCSP)[2] to synchronize the MARS Server databases within a
 LIS.  When SCSP is used to synchronize the caches of MARS Servers in
 a LIS, the LIS defines the boundary of an SCSP Server Group (SG).

1. Introduction

 The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
 SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this
 document, are to be interpreted as described in [5].
 The MARS is an extended analog of the ATMARP Server introduced in
 [4]. It provides the necessary connection and addressing services
 required by layer 3 multicast services over ATM. There are three
 basic elements to the MARS model. First, the MARS Server which
 manages and distributes layer 3 group membership information to the
 LIS. Second, MARS Clients which register with and query a single MARS
 Server for layer 3 multicast information. Third, MCS Clients which
 register with a single MARS Server and provide layer 3 multicast
 forwarding services for a LIS.
 Both MARS Clients and MCS Clients explicitly register with the MARS
 Server before exchanging layer 3 multicast information. During the
 registration process MARS Clients are place on the Cluster Control VC

Luciani & Gallo Experimental [Page 1] RFC 2443 MARS Service Using SCSP November 1998

 (CCVC) and MCS Clients are placed on the Server Control VC (SCVC).
 Both the CCVC and SCVC are then used to propagate layer 3 multicast
 updates to the clients which make up a LIS. During the registration
 process MARS Clients are also assigned a unique Cluster Member ID
 (CMI) which is used to identify reflected packets in the presence of
 MCS Clients.
 In the Distributed MARS Model there MAY be multiple MARS Servers in a
 given LIS, and since any MARS Server within the LIS MUST be able to
 provide layer 3 multicast information about any multicast group
 within the LIS, there MUST be a method by which to synchronize
 multicast information across all MARS Servers within the LIS.
 The Server Cache Synchronization Protocol (SCSP) solves the
 generalized server synchronization/cache-replication problem for
 distributed databases, and thus SCSP MAY be applied to the MARS
 Server database synchronization problem within a LIS. When SCSP is
 used to synchronize the caches of MARS Servers in a LIS, the LIS
 defines the boundary of and SCSP Server Group (SG).
 SCSP is defined in two parts: the protocol independent part and the
 client/server protocol specific part. The protocol independent part
 is specified in [2] whereas this document will specify the
 client/server protocol specific part where the MARS Server is the
 client/server protocol.

2. Overview

 All MARS Servers belonging to a LIS are said to belong to a Server
 Group (SG).  A SG is identified by, not surprisingly, its SGID which
 is contained in a field in all SCSP packets. All SCSP packets contain
 a Protocol ID (PID) field as well. This PID field is set to 0x0003 to
 signify that SCSP is synchronizing MARS Server databases as opposed
 to synchronizing some other protocol's databases. (see Section
 B.2.0.1 of [2] for more details).  In general, PIDs for SCSP will be
 assigned by IANA upon request given that a client/server protocol
 specific specification has been written. In the case of MARS Servers,
 the client/server protocol specific specification was written at the
 same time as SCSP, and thus a PID=0x0003 was assigned in [2].
 SCSP places no topological requirements upon a MARS Server SG.
 Obviously, however, the resultant graph of MARS Servers must span the
 set of MARS Servers being synchronized. For more information about
 the client/server protocol independent part of SCSP, the reader is
 encouraged to see [2].

Luciani & Gallo Experimental [Page 2] RFC 2443 MARS Service Using SCSP November 1998

 When a SG is using SCSP for synchronization, a MARS Client or MCS
 Client will register with only one MARS Server although it is allowed
 to choose any MARS Server in the SG for this registration. At
 registration time the MARS Client or MCS Client will be added to that
 MARS Servers respective CCVC or SCVC. Also, MARS Clients will be
 issued a unique CMI for the entire LIS. This document assumes at a
 minimum each MARS Server in the SG will be configured with a unique
 range of CMIs to assign to clients registering with that MARS Server.
 Use of some external means for allocating CMIs to MARS Servers in a
 SG is possible but beyond the scope of this document.
 When a MARS Client or MCS Client successfully registers with a MARS
 Server in the SG that MARS Server will propagate the registration
 information to its peer MARS Servers. The same propagation will occur
 for any subsequent group membership information learned from the
 clients. The peer MARS Server will then update its group membership
 database and propagate the information out its own CCVC or SCVC if
 needed.
 In the case of a MARS Server failure all peer MARS Servers in the SG
 MUST flush the client/group membership information learned from the
 failed MARS Server. The clients belonging to the failed MARS Servers
 CCVC and SCVC will migrate to the next available MARS Server as
 specified in Section 5.3 of [1]. When a client detects a failure of
 its MARS, it steps to the next backup MARS Server and attempts to
 register with the server. If the registration is successful the
 client will re-join all of its previous group membership information.
 If the registration fails, the process repeats until a functional
 MARS Server is found.
 Determining the operational state of a MARS Servers in a SG requires
 that each MARS Server send out an "alive" or "heartbeat" message
 similar to the MARS Redirect message sent out on the CCVC or SCVC for
 MARS Clients. However, this message will only be sent to MARS Servers
 in the SG and is from here on defined as the MARS Server Redirect
 Entry.
 In order to detect that a MARS Server failure has occurred each
 server MUST update it's MARS Server Redirect Entry state at least
 every 2 minutes, it is RECOMMENDED that it is updated every 1 minute.
 Failure to receive two consecutive MARS Server Redirect Entry updates
 from a given MARS Server in the SG will cause all membership
 information learned from this server to be flushed. The MARS Server
 Redirect Entry state is also used to create the MARS_REDIRECT_MAP
 messages sent out on CCVC for each MARS Server in the SG. The
 ordering of each server learned will be based on the MARS Servers
 SCSP Sender ID. The ordering of the MARS_REDIRECT_MAP will first

Luciani & Gallo Experimental [Page 3] RFC 2443 MARS Service Using SCSP November 1998

 contain the list of MARS Servers learned via MARS Server Redirect
 Entry updates in ascending order based on the SCSP Sender ID,
 followed by any externally configured or learned backup MARS Servers.
 In the case of a MARS Client or MCS Client failure where the client
 is unexpectedly removed from the CCVC or SCVC the MARS Server MUST
 notify its peer SG members via a proxy deregister for that client.
 Upon receiving a proxy deregister request from a peer SG member all
 membership information for the deregistering client MUST be removed.
 Any Clients sending multicast data to the failed client should also
 receive an unexpected removal of this client which will intern cause
 the sending client to revalidate the multicast groups current
 membership as outlined in Section 5.1.5.1 of [1].

3. Format of the CSA Record MARS Specific Part

 CSA Records in SCSP contain a "Client/Server Protocol Specific Part"
 which contains the non-protocol independent information for a given
 server's cache entry.
 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
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |        Hardware Type          |        Protocol Type          |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                              SNAP                             |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     SNAP      |   Unused      |    Version    |   State       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |            Flags              |       Cluster Member ID       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | Src Addr Len  | Group Addr Len| ATM Addr T/L  |ATM SubAddr T/L|
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Source Protocol Address             (variable length)     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Source ATM Address                  (variable length)     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Source ATM SubAddress               (variable length)     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Minimum Multicast Group Address     (variable length)     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Maximum Multicast Group Address     (variable length)     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Hardware Type
   Defines the type of "link layer" addresses being carried.  This
   value is the ATM Forum 'address family number' specified in [3] as
   15 decimal (0x000F).  This is the mar$afn field defined in [1].

Luciani & Gallo Experimental [Page 4] RFC 2443 MARS Service Using SCSP November 1998

 Protocol Type
   This field is the protocol type number for the protocol using MARS
   from [3].  (IPv4 is 0x0800).  This is the mar$pro.type field from
   [1].
 Protocol SNAP
   This field is the optional protocol SNAP extension to protocol
   type. This is the mar$pro.snap field from [1].
 Version Number
   0                    MARS Specific part of the CSA record.
   0x01                 Reserved for NHRP.
   0x02 - 0xEF          Reserved for future use by the IETF.
   0xF0 - 0xFE          Allocated for use by the ATM Forum.
   0xFF                 Experimental/Local use.
   Version Number for this document MUST be set to 0x00.
 State
   1   MARS Server Redirect Entry.
   2   MCS Serve/Register request.
   3   MARS Client Join/Register request.
   4   MARS Client Leave/Deregister request.
   5   MCS Unserve/Deregister request.
   All other State values should cause the CSA to be discarded.
 Flags
   The flags field is used to contain several flags and is similar to
   the mar$flags field from [1].
     mar$flags
        Bit 15   - mar$flags.layer3grp
        Bit 13   - mar$flags.register
        Bit 0-7  - mar$flags.sequence
     All remaining bits are reserved and MUST be zero. The
     mars$flags.sequence field is of local significance only to the
     Local Server (LS).
 Cluster Member CMI
   This field contains the CMI which uniquely identifies each endpoint
   within a LIS. This is the mar$cmi field from [1].
 Src Addr Len
   This field contains the length of the Source Protocol Address
   field.  For IPv4, the value is 4 if an address is specified. A null
   (non-existent) address MUST be coded as zero length, and no space
   allocated for it in the message body.  This is the mar$spln field
   from [1].

Luciani & Gallo Experimental [Page 5] RFC 2443 MARS Service Using SCSP November 1998

 Group Addr Len
   This field contains the length of the Group Protocol Address field.
   For IPv4, the value is 4 if an address is specified. A null (non-
   existent) address MUST be coded as zero length, and no space
   allocated for it in the message body.  This is the mar$tpln field
   from [1].
 ATM Addr T/L
   This field contains the type and length of the Source ATM Address
   field.  The type and length encoding is described in Section 5.1.2
   of [1].
 ATM SubAddr T/L
   This field contains the type and length of the Source ATM
   SubAddress field.  The type and length encoding is described in
   Section 5.1.2 of [1].
 Source Protocol Address
   This is the internetwork address for the source of an address
   binding in a MARS server cache entry. If null, no storage will be
   allocated.  This is the mar$spa field from [1].
 Source ATM Address
   This is the Source's ATM address of an address binding in a MARS
   server cache entry.  The address, if specified, is E.164 or ATM
   Forum NSAPA. This is the mar$sha field from [1].
 Source ATM SubAddress
   This is the Source's ATM subaddress of an address binding in a MARS
   server cache entry.  The subaddress, if specified, is an ATM Forum
   NSAPA.  If null, no storage will be allocated. This is the mar$ssa
   field from [1].
 Minimum Multicast Group Address
   This is the internetwork address of the lower bound on the range of
   multicast group addresses for the address binding in a MARS server
   cache entry. If null, no storage will be allocated. This is the
   mar$min.N field from [1].
 Maximum Multicast Group Address
   This is the internetwork address of the upper bound on the range of
   multicast group addresses for the address binding in a MARS server
   cache entry. If null, no storage will be allocated. This is the
   mar$max.N field from [1].

Luciani & Gallo Experimental [Page 6] RFC 2443 MARS Service Using SCSP November 1998

4. Values for SCSP Protocol Independent Part

 The following sections give values for fields of the SCSP Protocol
 Independent Part of the various SCSP messages.

4.1 Values for the SCSP "Mandatory Common Part"

 Protocol ID = 0x0003
 Sender ID Len = 0x04
 Recvr ID Len = 0x04
 See Section B.2.0.1 of [2] for a detailed description of these
 fields.

4.2 Values for the SCSP "CSAS Record"

 Cache Key Len = 0x04
 Orig ID Len = 0x04
 See Section B.2.0.2 of [2] for a detailed description of these
 fields.

5. Detailed State Descriptions

5.1 MARS Server Redirect Entry.

 The MARS Server Redirect Entry is used to determine the operational
 state of a MARS Server in the SG. Each server MUST update it's MARS
 Server Redirect Entry state at least every 2 minutes, it is
 RECOMMENDED that it is updated every 1 minute.
 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
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |        Hardware Type          |        Protocol Type          |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                              SNAP                             |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     SNAP      |   Unused      |    Version    |   State       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |            Flags              |       Cluster Member ID       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | Src Addr Len  | Group Addr Len| ATM Addr T/L  |ATM SubAddr T/L|
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Source ATM Address                  (variable length)     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Source ATM SubAddress               (variable length)     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Luciani & Gallo Experimental [Page 7] RFC 2443 MARS Service Using SCSP November 1998

 Hardware Type
   This value is the ATM Forum 'address family number' specified in
   [3] as 15 decimal (0x000F).
 Protocol Type
   This field is the protocol type number for the protocol using MARS
   from [3].  (IPv4 is 0x0800).
 Protocol SNAP
   This field is the optional protocol SNAP extension to protocol
   type.  This is the mar$pro.snap field from [1].
 Version Number
   Version Number for this document MUST be set to 0x00.
 State
   State value is coded as 1 decimal for a MARS Server Redirect Entry.
 The Flags, Cluster Member ID, Src Addr Len, and Group Addr Len fields
 are unused and set to zero.
 The ATM Addr T/L, ATM SubAddr T/L, Source ATM Address, and Source ATM
 SubAddress fields define the ATM address for the source of the MARS
 Server Redirect Entry in the SG. The coding for these fields are the
 same as described in Section 3 of this document.
 Failure to receive two consecutive MARS Server Redirect Entry updates
 from a given MARS Server in the SG will cause all membership
 information learned from this server to be flushed. When a valid MARS
 Server Redirect Entry update is received the source of this update
 will be placed into the table of backup MARS Servers sent in the
 MARS_REDIRECT_MAP message. The ordering of servers in the
 MARS_REDIRECT_MAP will first contain the list of MARS Servers learned
 via MARS Server Redirect Entry updates in ascending order based on
 the SCSP Sender ID, followed by any externally configured or learned
 backup MARS Servers. The format of the MARS_REDIRECT_MAP can be found
 in Section 5.4.3 of [1].

5.2 MCS Serve/Register request.

 The MCS Serve/Register request is used to propagate the registering
 or servicing of specific groups by an MCS Client within the SG
 domain. It is similar to an MARS_MSERV request defined in Section
 6.2.2 and 6.2.3 of [1]. When a MARS Server in the SG successfully
 adds a new MCS Client to it's SCVC or adds MCS support for a specific
 group it MUST send a MCS Serve/Register request to the SG. An MCS
 Client can only register with one MARS Server in the SG.

Luciani & Gallo Experimental [Page 8] RFC 2443 MARS Service Using SCSP November 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
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |        Hardware Type          |        Protocol Type          |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                              SNAP                             |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     SNAP      |   Unused      |    Version    |   State       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |            Flags              |       Cluster Member ID       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | Src Addr Len  | Group Addr Len| ATM Addr T/L  |ATM SubAddr T/L|
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Source Protocol Address             (variable length)     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Source ATM Address                  (variable length)     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Source ATM SubAddress               (variable length)     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Minimum Multicast Group Address     (variable length)     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Maximum Multicast Group Address     (variable length)     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Hardware Type
   This value is the ATM Forum 'address family number' specified in
   [3] as 15 decimal (0x000F).
 Protocol Type
   This field is the protocol type number for the protocol using MARS
   from [3].  (IPv4 is 0x0800).
 Protocol SNAP
   This field is the optional protocol SNAP extension to protocol
   type.  This is the mar$pro.snap field from [1].
 Version Number
   Version Number for this document MUST be set to 0x00.
 State
   State value is coded as 2 decimal for a MCS Serve/Register request.
 Flags
   The flags field is used to contain several flags:

Luciani & Gallo Experimental [Page 9] RFC 2443 MARS Service Using SCSP November 1998

     mar$flags
        Bit 15   - mar$flags.layer3grp
        Bit 13   - mar$flags.register
        Bit 0-7  - mar$flags.sequence
   The mar$flags.register bit MUST be set the same as in the
   originating MARS_MSERV request. The mar$flags.layer3grp bit MUST be
   zero and the mar$flags.sequence bits are of local significance only
   to the LS.
 Cluster Member CMI
   This field contains the CMI assigned by the MARS Server which
   processed the MARS_MSERV request and uniquely identifies the MCS
   Client in the MARS server cache.
 Src Addr Len
   This field contains the length of the Source Protocol Address
   field.  For IPv4, the value is 4 if an address is specified. A null
   (non-existent) address MUST be coded as zero length, and no space
   allocated for it in the message body.
 Group Addr Len
   This field contains the length of the Group Protocol Address field.
   If the register bit in the flags field is set to 1 in the request
   this field MUST be zero.  If the register bit is zero in the flags
   field the value of this field for IPv4 is 4.
 ATM Addr T/L
   This field contains the type and length of the Source ATM Address
   field for the MCS Client that originated the MARS_MSERV request.
   The type and length encoding is described in Section 3.
 ATM SubAddr T/L
   This field contains the type and length of the Source ATM
   SubAddress field for the MCS Client that originated the MARS_MSERV
   request.  The type and length encoding is described in Section 3.
 Source Protocol Address
   This is the internetwork address for the source of an address
   binding in a MARS server cache entry. If Src Addr Len is set to
   zero no storage will be allocated.
 Source ATM Address
   This is the MCS Client's ATM address of an address binding in a
   MARS server cache entry. The address is E.164 or ATM Forum NSAPA.

Luciani & Gallo Experimental [Page 10] RFC 2443 MARS Service Using SCSP November 1998

 Source ATM SubAddress
   This is the MCS Client's ATM subaddress of an address binding in a
   MARS server cache entry. The subaddress, if specified, is an ATM
   Forum NSAPA.  If null, no storage will be allocated.
 Minimum Multicast Group Address
   This is the internetwork address of the lower bound on the range of
   multicast group addresses for the address binding in a MARS server
   cache entry. If Group Addr Len is set to zero no storage will be
   allocated.
 Maximum Multicast Group Address
   This is the internetwork address of the upper bound on the range of
   multicast group addresses for the address binding in a MARS server
   cache entry. If Group Addr Len is set to zero no storage will be
   allocated.
 An MCS Client can only register with one MARS Server in the SG and is
 only placed on the SCVC for the MARS Server for which it is
 registered with.
 When a MCS Client Serve/Register request specifying a group address
 is received by a MARS Server it MUST create a cache entry associated
 with this client. In addition to adding the cache entry it MUST send
 out a MARS_MIGRATE message on it's CCVC. This is needed so that
 clients using a mesh topology can migrate to a server based topology.
 Details regarding the MARS_MIGRATE message can be found in Section
 5.1.6 of [1].

5.3 MARS Client Join/Register request.

 The MARS Client Join/Register request is used to propagate the
 registering or joining of specific group ranges by MARS Clients
 within the SG domain.  It is similar to the MARS_JOIN request defined
 in Sections 5.2.1 to 5.2.3 of [1]. When a MARS Server in the SG
 successfully registers a new MARS Client or a registered client joins
 a specific group address range the MARS Server MUST send a MARS
 Client Join/Register request to the SG. A MARS Client can only
 register with one MARS Server in the SG and is placed only on that
 servers CCVC.

Luciani & Gallo Experimental [Page 11] RFC 2443 MARS Service Using SCSP November 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
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |        Hardware Type          |        Protocol Type          |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                              SNAP                             |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     SNAP      |   Unused      |    Version    |   State       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |            Flags              |       Cluster Member ID       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | Src Addr Len  | Group Addr Len| ATM Addr T/L  |ATM SubAddr T/L|
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Source Protocol Address             (variable length)     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Source ATM Address                  (variable length)     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Source ATM SubAddress               (variable length)     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Minimum Multicast Group Address     (variable length)     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |     Maximum Multicast Group Address     (variable length)     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Hardware Type
   This value is the ATM Forum 'address family number' specified in
   [3] as 15 decimal (0x000F).
 Protocol Type
   This field is the protocol type number for the protocol using MARS
   from [3].  (IPv4 is 0x0800).
 Protocol SNAP
   This field is the optional protocol SNAP extension to protocol
   type.  This is the mar$pro.snap field from [1].
 Version Number
   Version Number for this document MUST be set to 0x00.
 State
   State value is coded as 3 decimal for a MARS Client Join/Register
   request.

Luciani & Gallo Experimental [Page 12] RFC 2443 MARS Service Using SCSP November 1998

 Flags
   The flags field is used to contain several flags:
     mar$flags
        Bit 15   - mar$flags.layer3grp
        Bit 13   - mar$flags.register
        Bit 0-7  - mar$flags.sequence
   The mars$flags.layer3grp and mar$flags.register bits MUST be set
   the same as in the originating MARS_JOIN request. The
   mar$flags.sequence bits are of local significance only to the LS.
 Cluster Member CMI
   This field contains the CMI assigned by the MARS Server which
   processed the MARS_JOIN request and uniquely identifies the MARS
   Client in the MARS server cache.
 Src Addr Len
   This field contains the length of the Source Protocol Address
   field.  For IPv4, the value is 4 if an address is specified. A null
   (non-existent) address MUST be coded as zero length, and no space
   allocated for it in the message body.
 Group Addr Len
   This field contains the length of the Group Protocol Address field.
   If the register bit in the flags field is set to 1 in the request
   this field MUST be zero.  If the register bit is zero in the flags
   field the value of this field for IPv4 is 4.
 ATM Addr T/L
   This field contains the type and length of the Source ATM Address
   field for the MARS Client that originated the MARS_JOIN request.
   The type and length encoding is described in Section 3.
 ATM SubAddr T/L
   This field contains the type and length of the Source ATM
   SubAddress field for the MARS Client that originated the MARS_JOIN
   request.  The type and length encoding is described in Section 3.
 Source Protocol Address
   This is the internetwork address for the source of an address
   binding in a MARS server cache entry. If Src Addr Len is set to
   zero no storage will be allocated.
 Source ATM Address
   This is the MARS Client's ATM address of an address binding in a
   MARS server cache entry. The address is E.164 or ATM Forum NSAPA.

Luciani & Gallo Experimental [Page 13] RFC 2443 MARS Service Using SCSP November 1998

 Source ATM SubAddress
   This is the MARS Client's ATM subaddress of an address binding in a
   MARS server cache entry. The subaddress, if specified, is an ATM
   Forum NSAPA.  If null, no storage will be allocated.
 Minimum Multicast Group Address
   This is the internetwork address of the lower bound on the range of
   multicast group addresses for the address binding in a MARS server
   cache entry. If Group Addr Len is set to zero no storage will be
   allocated.
 Maximum Multicast Group Address
   This is the internetwork address of the upper bound on the range of
   multicast group addresses for the address binding in a MARS server
   cache entry. If Group Addr Len is set to zero no storage will be
   allocated.
 An MARS Client can only register with one MARS Server in the SG and
 is only placed on the CCVC for the MARS Server for which it is
 registered with. If the mar$flags.layer3grp is set to 1 than the
 Minimum and Maximum Multicast Group Addresses MUST be equal for IPv4.
 When a MARS Client Join/Register request is sent with the
 mar$flags.register bit set to 1 all of the servers in the SG will
 create a cache entry for this client using the information in the
 request.
 When a registered MARS Client issues a MARS_JOIN for a specific group
 address range a MARS Client Join/Register request MUST be sent to the
 servers in the SG. The actions taken by each server in the SG depend
 on previous group membership actions and MCS supported groups.
 Each MARS Server MUST perform the necessary redistribution and hole
 punching algorithms before propagating this request to the CCVC and
 SCVC on each server. The redistribution and hole punching algorithms
 used for propagating join requests to the CCVC are the same as
 defined in Sections 6.1.2 and 6.2.4 of [1]. If the originating
 MARS_JOIN request is a duplicate of a previously joined range or
 contains no group address range than a MARS Client Join/Register MUST
 NOT be sent to the SG.
 The redistribution and hole punching algorithms used for propagating
 join requests as MARS_SJOIN request on a SCVC is the same as Section
 6.2.4 except for the following. Only the MARS Servers which contain
 the registered MCS Clients for the target group ranges should
 propagate this information to their SCVCs.

Luciani & Gallo Experimental [Page 14] RFC 2443 MARS Service Using SCSP November 1998

5.4 MARS Client Leave/Deregister request.

 The MARS Client Leave/Deregister request is used to propagate the
 deregistering or leaving of specific group ranges by registered MARS
 Clients within the SG domain. It is similar to the MARS_LEAVE request
 defined in Sections 5.2.1 to 5.2.3 of [1]. When a MARS Server in the
 SG successfully deregisters a registered MARS Client or a registered
 client leaves a specific group address range for which it had joined
 the MARS Server MUST send a MARS Client Leave/Deregister request to
 the SG. If a registered MARS Client is unexpectedly removed from the
 CCVC the MARS Server MUST act as a proxy and send a MARS Client
 Leave/Deregister request to the SG.
 The format and meanings of the fields in a MARS Client
 Leave/Deregister request are the same as in Section 5.3 except the
 State is coded as 4 decimal for a MARS Client Leave/Deregister
 request.
 When a MARS Client Leave/Deregister request is sent with the
 mar$flags.register bit set to 1 all of the servers in the SG
 receiving this update MUST purge all cache entries for this client.
 When a registered MARS Client issues a MARS_LEAVE for a specific
 group address range a MARS Client LEAVE/Deregister request MUST be
 sent to the servers in the SG. The actions taken by each server in
 the SG depend on previous group membership actions and MCS supported
 groups.
 Each MARS Server MUST perform the necessary redistribution and hole
 punching algorithms before propagating this request to the CCVC and
 SCVC on each server. The redistribution and hole punching algorithms
 used for propagating leave requests to the CCVC are the same as
 defined in Sections 6.1.2 and 6.2.4 of [1]. If the originating
 MARS_LEAVE request does not correspond to a previously joined range
 or contains no group address range than a MARS Client
 Leave/Deregister MUST NOT be sent to the SG.
 The redistribution and hole punching algorithms used for propagating
 leave requests as MARS_SLEAVE requests on a SCVC is the same as
 Section 6.2.4 except for the following. Only the MARS Servers which
 contain the registered MCS Clients for the target group ranges should
 propagate this information to their SCVCs.

5.5 MCS Unserve/Deregister request.

 The MCS Unserve/Deregister request is used to propagate the
 deregistering or unservicing of specific groups by a registered MCS
 Client within the SG domain. It is similar to an MARS_MUNSERV request

Luciani & Gallo Experimental [Page 15] RFC 2443 MARS Service Using SCSP November 1998

 defined in Section 6.2.2 and 6.2.3 of [1]. When a MARS Server in the
 SG successfully deregisters a registered MCS Client or registered MCS
 Client stops serving a specific group address range for which it had
 serviced the MARS Server MUST send a MCS Unserve/Deregister request
 to the SG. If a registered MCS Client is unexpectedly removed from
 the SCVC the MARS Server owning the SCVC MUST act as a proxy and send
 a MCS Unserve/Deregister request to the SG.
 The format and meanings of the fields in a MCS Unserve/Deregister
 request are the same as in Section 5.2 except the State is coded as 5
 decimal for a MCS Unserve/Deregister request.
 When a MCS Client Unserve/Deregister request is sent with the
 mar$flags.register bit set to 1 all of the servers in the SG
 receiving this update MUST purge all cache entries for this client.
 When a registered MCS Client issues a MARS_MUNSERV for a specific
 group address range being served a MCS Client Unserve/Deregister
 request MUST be sent to the servers in the SG. The members of the SG
 that receive this update must then clear the cache entry associated
 with this MCS Client.
 In addition to clearing one or more cache entries associated with
 receiving a  MCS Client Unserve/Deregister request each MARS Server
 in the SG MUST send out a MARS_LEAVE message on it's CCVC in order
 for clients to change back to a mesh topology.

6. Security Considerations

 There is no mechanism to encrypt the CSA Record MARS Specific Part of
 the message exchanged between servers. However, there are base SCSP
 security features in the SCSP Protocol Independent part [2] which can
 be used to protect against attacks.
 Any SCSP MARS is susceptible to Denial of Service (DOS) attacks. A
 rouge MARS Client can inundate its Server with MARS packets. This is
 a base MARS problem as currently defined by [1]. A rouge host can
 also inundate its neighboring SCSP MARS with SCSP packets. However,
 if the authentication option is used, the SCSP MARS databases will
 not become corrupted, as the bogus packets will be discarded when the
 authentication check fails.
 Due to the pair wise authentication model of SCSP MARS, the
 information received from any properly authenticated server is
 trusted and propagated throughout the server group. Consequently, if
 security of any SCSP MARS server is compromised, the entire database
 becomes vulnerable to corruption originating from the compromised
 server.

Luciani & Gallo Experimental [Page 16] RFC 2443 MARS Service Using SCSP November 1998

References

 [1] Armitage, G., "Support for Multicast over UNI 3.0/3.1 based ATM
     Networks", RFC 2022, November 1996.
 [2] Luciani, J., Armitage, G., Halpern, J. and N. Doraswamy, "Server
     Cache Synchronization Protocol", RFC 2334, April 1998.
 [3] Reynolds, J. and J. Postel, "Assigned Numbers", STD 2, RFC 1700,
     October 1994.  See also: http://www.iana.org/numbers.html
 [4] Laubach, M., "Classic IP and ARP over ATM", RFC 1577, January
     1994.
 [5] Bradner, S., "Key Words for use in RFCs to Indicate Requirement
     Levels," BCP 14, RFC 2119, March 1997.

Acknowledgments

 The authors would like to thank Grenville Armitage for his previous
 distributed MARS work and also the members of the ION working group
 of the IETF, whose review and discussion of this document has been
 invaluable.

Authors' Addresses

 James V. Luciani
 Bay Networks, Inc.
 3 Federal Street, BL3-04
 Billerica, MA  01821
 Phone: +1-508-916-4734
 EMail: luciani@baynetworks.com
 Anthony M. Gallo
 IBM, Networking Hardware Division
 Dept. M6LA/B664
 P.O. Box 12195
 Research Triangle Park, NC 27709
 Phone: +1-919-254-9889
 EMail: gallo@raleigh.ibm.com

Luciani & Gallo Experimental [Page 17] RFC 2443 MARS Service Using SCSP November 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.

Luciani & Gallo Experimental [Page 18]

/data/webs/external/dokuwiki/data/pages/rfc/rfc2443.txt · Last modified: 1998/11/13 23:22 by 127.0.0.1

Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki