GENWiki

Premier IT Outsourcing and Support Services within the UK

User Tools

Site Tools


rfc:rfc5186

Network Working Group B. Haberman Request for Comments: 5186 Johns Hopkins University Category: Informational J. Martin

                                                         Woven Systems
                                                              May 2008
      Internet Group Management Protocol Version 3 (IGMPv3) /
        Multicast Listener Discovery Version 2 (MLDv2) and
               Multicast Routing Protocol Interaction

Status of This Memo

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

Abstract

 The definitions of the Internet Group Management Protocol Version 3
 (IGMPv3) and Multicast Listener Discovery Version 2 (MLDv2) require
 new behavior within the multicast routing protocols.  The additional
 source information contained in IGMPv3 and MLDv2 messages
 necessitates that multicast routing protocols manage and utilize the
 information.  This document describes how multicast routing protocols
 will interact with these source-filtering group management protocols.

1. Introduction

 The definitions of IGMPv3 [IGMP3] and MLDv2 [MLDv2] require new
 behavior within the multicast routing protocols.  The additional
 source information contained in IGMPv3 and MLDv2 messages
 necessitates that multicast routing protocols manage and utilize the
 information.  This document will describe how multicast routing
 protocols will interpret information learned from these source-
 filtering group management protocols.

2. Multicast Forwarding State

 Existing multicast routing protocols utilize the group management
 database in determining if local members exist for a particular
 multicast group.  With previous group management protocols, this
 database had one type of record indicating the group for which there
 was interest and the associated local interfaces.

Haberman & Martin Informational [Page 1] RFC 5186 IGMPv3/MLDv2 and Multicast Protocols May 2008

 In the case of IGMPv3 and MLDv2, these routing protocols may now
 build multicast forwarding state based on the source filter
 information available for each multicast group that has local
 membership.  This requires that the group management database have
 four record types.  Only one record may exist for a given interface
 and a given multicast group.
    1. EXCLUDE <>
       The EXCLUDE <> record indicates interest in all sources
       destined to this group address for a set of local interfaces.
       It is equivalent to the single record type existing in previous
       versions of the group management protocols.
    2. INCLUDE <>
       The INCLUDE <> record indicates that there is no interest in
       any sources destined to this group address for a set of local
       interfaces.
    3. EXCLUDE <list>
       The EXCLUDE <list> record indicates that there is interest in
       all sources other than the specifically listed sources for a
       set of local interfaces.
    4. INCLUDE <list>
       The INCLUDE <list> record indicates that there is interest in
       only the specifically listed sources for a set of local
       interfaces.
 The records in the group management database should be utilized when
 generating forwarding state for a multicast group.  If the source
 address in the multicast packet exists in the database for the
 specified multicast group and is in an INCLUDE list or is not listed
 in an EXCLUDE list, the multicast routing protocol should add the
 interface to the list of downstream interfaces; otherwise, it should
 not be added based on local group membership.

3. DVMRP Interaction

 The Distance Vector Multicast Routing Protocol (DVMRP) [DVMRP] does
 not incorporate any knowledge of the multicast group's senders.
 Therefore, DVMRP will act only on the multicast group address
 contained in an IGMPv3 or MLDv2 report.
 Future standardized versions of DVMRP may incorporate pruning and
 grafting messages similar to PIM-DM (discussed in Section 5).  The
 rules defined in Section 5 can be applied in this situation.

Haberman & Martin Informational [Page 2] RFC 5186 IGMPv3/MLDv2 and Multicast Protocols May 2008

4. MOSPF Interaction

 In Multicast Extensions to OSPF (MOSPF) [MOSPF], the consideration of
 source filter information in the group management database is limited
 to the building of forwarding state (discussed above).  This is due
 to the flooding of group-membership-LSAs within MOSPF.

5. PIM-DM Interaction

 The PIM-DM protocol [PIMDM] interaction with a source-filtering group
 management protocol is important in two areas: multicast distribution
 tree pruning and multicast distribution tree grafting.  The following
 sections will describe the behavior needed in PIM-DM to interoperate
 with IGMPv3 and MLDv2.

5.1. PIM-DM Prunes

 PIM-DM prune messages are initiated when a PIM-DM router determines
 that there are no entities interested in the data flowing on the
 (S,G) forwarding state.  If the multicast router is running IGMPv3 or
 MLDv2, this is determined by the source S being in EXCLUDE state in
 the source filter for the destination G, or all interest in G being
 terminated for an existing (S,G) forwarding entry.

5.2. PIM-DM Grafts

 PIM-DM graft messages are sent in order to override an existing PIM-
 DM prune.  In the case of IGMPv3 or MLDv2, this occurs when prune
 state exists for (S,G) and a state change occurs in which the source
 filter state for S changes to INCLUDE for the specified G.

6. PIM-SM Interaction

 A PIM-SM interaction takes place when a PM-SM [PIMSM] router receives
 an IGMP or MLD message regarding a group address that is in the Any
 Source Multicast (ASM) range.  This range is defined as the entire
 multicast address space excluding the global SSM range [SSM] and any
 locally defined Source Specific space.

Haberman & Martin Informational [Page 3] RFC 5186 IGMPv3/MLDv2 and Multicast Protocols May 2008

6.1. PIM-SM Joins (ASM Behavior)

 PIM-SM join messages are initiated when a PIM-SM router determines
 that there are entities interested in a specific group or a specific
 source sending to the group.  If this is due to an IGMPv3 or MLDv2
 report with a zero-length EXCLUDE list, then the join is sent as a
 (*,G) join towards the RP.
 If the join is triggered by an IGMPv3 or MLDv2 state change that
 affects source information, the PIM-SM join is sent as a (S,G) join
 towards the specific source.  This behavior optimizes the join
 process, as well as facilitates the adoption of the SSM model.  The
 generation of this (S,G) join can cause failures in architectures
 where leaf routers do not have global reachability, and thus, can be
 overridden by local policy.  If this is the case, then all triggered
 joins are sent towards the RP as (*,G) joins.  The router sending the
 (*,G) join is responsible for filtering the data as per the IGMPv3
 database before forwarding.

6.2. PIM-SM Prunes (ASM Behavior)

 PIM-SM prune messages are initiated when a PIM-SM router determines
 that there are no entities interested in a specific group, or a
 specific source sending to the group.  If this is triggered by either
 receiving a report with an EXCLUDE or if a specific Source/Group
 times out, then an (S,G) prune is sent towards the upstream router.
 If all of the IGMPv3 or MLDv2 derived requests for a group time out,
 then (S,G) and (*,G) prunes are sent upstream as needed to stop all
 flow of traffic for that group.

7. PIM-SSM Interaction

 A PIM-SSM interaction takes place when a PIM-SM router receives an
 IGMPv3 or MLDv2 message regarding a group address that is in the
 Source Specific Multicast range.  This behavior is not defined in
 this document, but rather in [PIMSM].

8. Security Considerations

 This document does not introduce any additional security issues above
 and beyond those already discussed in [PIMDM], [PIMSM], [IGMP3], and
 [MLDv2].

9. Acknowledgements

 The authors would like to thank Murali Brahmadesam, Leonard Giuliano,
 and Hal Sandick for their feedback and suggestions.

Haberman & Martin Informational [Page 4] RFC 5186 IGMPv3/MLDv2 and Multicast Protocols May 2008

10. Normative References

 [IGMP3] Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A.
         Thyagarajan, "Internet Group Management Protocol, Version 3",
         RFC 3376, October 2002.
 [MLDv2] Vida, R., Ed., and L. Costa, Ed., "Multicast Listener
         Discovery Version 2 (MLDv2) for IPv6", RFC 3810, June 2004.
 [DVMRP] Waitzman, D., Partridge, C., and S. Deering, "Distance Vector
         Multicast Routing Protocol", RFC 1075, November 1988.
 [MOSPF] Moy, J., "Multicast Extensions to OSPF", RFC 1584, March
         1994.
 [PIMDM] Adams, A., Nicholas, J., and W. Siadak, "Protocol Independent
         Multicast - Dense Mode (PIM-DM): Protocol Specification
         (Revised)", RFC 3973, January 2005.
 [PIMSM] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas,
         "Protocol Independent Multicast - Sparse Mode (PIM-SM):
         Protocol Specification (Revised)", RFC 4601, August 2006.
 [SSM]   Holbrook, H. and B. Cain, "Source-Specific Multicast for IP",
         RFC 4607, August 2006.

Authors' Addresses

 Brian Haberman
 The Johns Hopkins University Applied Physics Laboratory
 11100 Johns Hopkins Road
 Laurel, MD  20723-6099
 US
 Phone: +1 443 778 1319
 EMail: brian@innovationslab.net
 Jim Martin
 Woven Systems
 2455 Augustine Drive, Suite 211
 Santa Clara, CA  95054
 US
 Phone: +1 408 654-8143
 EMail: jim@wovensystems.com

Haberman & Martin Informational [Page 5] RFC 5186 IGMPv3/MLDv2 and Multicast Protocols May 2008

Full Copyright Statement

 Copyright (C) The IETF Trust (2008).
 This document is subject to the rights, licenses and restrictions
 contained in BCP 78, and except as set forth therein, the authors
 retain all their rights.
 This document and the information contained herein are provided on an
 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
 THE INTERNET ENGINEERING TASK FORCE DISCLAIM 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.

Intellectual Property

 The IETF takes no position regarding the validity or scope of any
 Intellectual Property Rights or other rights that might be claimed to
 pertain to the implementation or use of the technology described in
 this document or the extent to which any license under such rights
 might or might not be available; nor does it represent that it has
 made any independent effort to identify any such rights.  Information
 on the procedures with respect to rights in RFC documents can be
 found in BCP 78 and BCP 79.
 Copies of IPR disclosures made to the IETF Secretariat and any
 assurances of licenses to be made available, or the result of an
 attempt made to obtain a general license or permission for the use of
 such proprietary rights by implementers or users of this
 specification can be obtained from the IETF on-line IPR repository at
 http://www.ietf.org/ipr.
 The IETF invites any interested party to bring to its attention any
 copyrights, patents or patent applications, or other proprietary
 rights that may cover technology that may be required to implement
 this standard.  Please address the information to the IETF at
 ietf-ipr@ietf.org.

Haberman & Martin Informational [Page 6]

/data/webs/external/dokuwiki/data/pages/rfc/rfc5186.txt · Last modified: 2008/05/29 18:23 by 127.0.0.1

Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki