PIM Multi-Topology ID (MT-ID) Join Attribute
RFC 6420

Internet Engineering Task Force (IETF)                            Y. Cai
Request for Comments: 6420                                         H. Ou
Category: Standards Track                            Cisco Systems, Inc.
ISSN: 2070-1721                                            November 2011

              PIM Multi-Topology ID (MT-ID) Join Attribute

Abstract

   This document introduces a new type of PIM Join Attribute that
   extends PIM signaling to identify a topology that should be used when
   constructing a particular multicast distribution tree.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc6420.

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   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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Cai & Ou                     Standards Track                    [Page 1]
RFC 6420                PIM MT-ID Join Attribute           November 2011

Table of Contents

   1. Introduction ....................................................2
   2. Terminology .....................................................3
   3. Functional Overview .............................................4
      3.1. PIM RPF Topology ...........................................4
      3.2. PIM MT-ID ..................................................6
      3.3. Applicability ..............................................7
   4. Protocol Specification of PIM MT-ID .............................7
      4.1. PIM MT-ID Hello Option .....................................7
      4.2. PIM MT-ID Join Attribute ...................................7
           4.2.1. Sending PIM MT-ID Join Attribute ....................7
           4.2.2. Receiving PIM MT-ID Join Attribute ..................8
           4.2.3. Validating PIM MT-ID Join Attribute .................8
           4.2.4. Conflict Resolution .................................9
                  4.2.4.1. Conflict Resolution Rules for
                           Upstream Routers ..........................10
                  4.2.4.2. Conflict Resolution Rules for
                           Downstream Routers ........................10
   5. Packet Format ..................................................10
      5.1. PIM MT-ID Hello Option ....................................11
      5.2. PIM MT-ID Join Attribute TLV Format .......................11
   6. IANA Considerations ............................................11
      6.1. PIM MT-ID Hello Option ....................................11
      6.2. PIM MT-ID Join Attribute Type .............................12
   7. Security Considerations ........................................12
   8. Acknowledgments ................................................12
   9. References .....................................................12
      9.1. Normative References ......................................12
      9.2. Informative References ....................................13

1.  Introduction

   Some unicast protocols, such as OSPF and IS-IS, allow a single
   network to be viewed as multiple topologies [RFC4915] [RFC5120].
   Deploying multi-topology (MT) routing allows different paths through
   the network to be selected to support different traffic or to offer
   protection paths in the event of failures.

   PIM [RFC4601] employs a technique known as Reverse Path Forwarding
   (RPF) to construct forwarding trees between multicast sources and
   receivers.  The procedure of RPF uses topology information provided
   by routing protocols, such as OSPF and IS-IS.  Using the PIM MT-ID
   Join Attribute specified in this document enables PIM to access the
   multiple topologies created by the routing protocols and construct
   multicast forwarding trees using separate network paths even when the