Internet Group Management Protocol Version 3 (IGMPv3) / Multicast Listener Discovery Version 2 (MLDv2) and Multicast Routing Protocol Interaction
The information below is for an old version of the document that is already published as an RFC.
This is an older version of an Internet-Draft that was ultimately published as RFC 5186.
|Last updated||2015-10-14 (Latest revision 2003-10-26)|
|RFC stream||Internet Engineering Task Force (IETF)|
|Additional resources||Mailing list discussion|
|IESG||IESG state||RFC 5186 (Informational)|
|Responsible AD||Margaret Cullen|
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MAGMA Working Group B. Haberman Internet Draft Caspian Networks draft-ietf-magma-igmpv3-and-routing-05.txt J. Martin October 2003 Netzwert AG Expires April 2004 IGMPv3/MLDv2 and Multicast Routing Protocol Interaction Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026 [RFC 2026]. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Abstract The definitions of IGMPv3 and MLDv2 require new behavior within the multicast routing protocols. The additional source information contained in IGMPv3 and MLDv2 messages necessitates multicast routing protocols to 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 multicast routing protocols to 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 Haberman, Martin 1 Internet Draft IGMPv3/MLDv2 and Multicast Protocols October 2003 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. 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 the group management database to 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 only 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 DVMRP protocol[DVMRP] 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 DVMRP to interoperate with IGMPv3 and MLDv2. 3.1 DVMRP Prunes Haberman, Martin 2 Internet Draft IGMPv3/MLDv2 and Multicast Protocols October 2003 DVMRP prune messages are initiated when a DVMRP 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. 3.2 DVMRP Grafts DVMRP graft messages are sent in order to override an existing DVMRP 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. 4. MOSPF Interaction In 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 Like DVMRP, PIM-DM[PIMDM] must utilize the source filter information when generating Prune and Graft messages. The following sections describe the creation of these message types. 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 Haberman, Martin 3 Internet Draft IGMPv3/MLDv2 and Multicast Protocols October 2003 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. 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 a 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 [PIMSM], [IGMP3], and [MLDv2]. Haberman, Martin 4 Internet Draft IGMPv3/MLDv2 and Multicast Protocols October 2003 9. Acknowledgements The authors would like to thank Murali Brahmadesam, Leonard Giuliano, and Hal Sandick for their feedback and suggestions. 10. Authors' Addresses Brian Haberman Caspian Networks 753 Bridgewater Drive Sykesville, MD 21784 email@example.com +1-410-552-1421 Jim Martin Netzwert AG An den Treptowers 1 D-12435 Berlin jim@Netzwert.AG +49.30/5 900 800-180 11. References 11.1 Normative References [IGMP3] B. Cain, et al, "Internet Group Management Protocol, Version 3", RFC 3376, October 2002. [MLDv2] R. Vida, et al., Multicast Listener Discovery Version 2 (MLDv2) for IPv6, work in progress. [DVMRP] T. Pusateri, "Distance Vector Multicast Routing Protocol", work in progress. [MOSPF] J. Moy, "Multicast Extensions to OSPF", RFC 1584, March 1994. [PIMDM] A. Adams, et al, "Protocol Independent Multicast - Dense Mode: Protocol Specification (Revised)", work in progress. [PIMSM] B.Fenner, et al, "Protocol Independent Multicast -Sparse Mode (PIM-SM): Protocol Specification (Revised)", work in progress. [SSM] H. Holbrook, et al, "Source-Specific Multicast for IP", work in progress. Haberman, Martin 5 Internet Draft IGMPv3/MLDv2 and Multicast Protocols October 2003 Full Copyright Statement Copyright (C) The Internet Society (2003). 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. This document expires in April, 2004. Haberman, Martin 6