Multicast Router Discovery
RFC 4286

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Network Working Group                                        B. Haberman
Request for Comments: 4286                                       JHU APL
Category: Standards Track                                      J. Martin
                                                             Netzwert AG
                                                           December 2005

                       Multicast Router Discovery

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 (2005).

Abstract

   The concept of Internet Group Management Protocol (IGMP) and
   Multicast Listener Discovery (MLD) snooping requires the ability to
   identify the location of multicast routers.  Since snooping is not
   standardized, there are many mechanisms in use to identify the
   multicast routers.  However, this can lead to interoperability issues
   between multicast routers and snooping switches from different
   vendors.

   This document introduces a general mechanism that allows for the
   discovery of multicast routers.  This new mechanism, Multicast Router
   Discovery (MRD), introduces a standardized means of identifying
   multicast routers without a dependency on particular multicast
   routing protocols.

Haberman, et al.            Standards Track                     [Page 1]
RFC 4286               Multicast Router Discovery          December 2005

Table of Contents

   1. Introduction ....................................................3
   2. Protocol Overview ...............................................3
   3. Multicast Router Advertisement ..................................4
      3.1. Advertisement Configuration Variables ......................4
           3.1.1. AdvertisementInterval ...............................5
           3.1.2. AdvertisementJitter .................................5
           3.1.3. MaxInitialAdvertisementInterval .....................5
           3.1.4. MaxInitialAdvertisements ............................5
           3.1.5. NeighborDeadInterval ................................5
           3.1.6. MaxMessageRate ......................................6
      3.2. Advertisement Packet Format ................................6
           3.2.1. Type Field ..........................................6
           3.2.2. Advertisement Interval Field ........................6
           3.2.3. Checksum Field ......................................6
           3.2.4. Query Interval Field ................................7
           3.2.5. Robustness Variable Field ...........................7
      3.3. IP Header Fields ...........................................7
           3.3.1. Source Address ......................................7
           3.3.2. Destination Address .................................7
           3.3.3. Time-to-Live / Hop Limit ............................7
           3.3.4. IPv4 Protocol .......................................7
           3.3.5. IPv6 Next Header ....................................7
      3.4. Sending Multicast Router Advertisements ....................8
      3.5. Receiving Multicast Router Advertisements ..................8
   4. Multicast Router Solicitation ...................................9
      4.1. Solicitation Packet Format .................................9
           4.1.1. Type Field ..........................................9
           4.1.2. Reserved Field ......................................9
           4.1.3. Checksum Field ......................................9
      4.2. IP Header Fields ..........................................10
           4.2.1. Source Address .....................................10
           4.2.2. Destination Address ................................10
           4.2.3. Time-to-Live / Hop Limit ...........................10
           4.2.4. IPv4 Protocol ......................................10
           4.2.5. IPv6 Next Header ...................................10
      4.3. Sending Multicast Router Solicitations ....................10
      4.4. Receiving Multicast Router Solicitations ..................10
   5. Multicast Router Termination ...................................11
      5.1. Termination Packet Format .................................11
           5.1.1. Type Field .........................................11
           5.1.2. Reserved Field .....................................11
           5.1.3. Checksum Field .....................................11
      5.2. IP Header Fields ..........................................12
           5.2.1. Source Address .....................................12
           5.2.2. Destination Address ................................12