The Protocol Independent Multicast (PIM) Join Attribute Format
RFC 5384

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Network Working Group                                           A. Boers
Request for Comments: 5384                                   I. Wijnands
Category: Standards Track                                       E. Rosen
                                                     Cisco Systems, Inc.
                                                           November 2008

               The Protocol Independent Multicast (PIM)
                         Join Attribute Format

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) 2008 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.

Abstract

   A "Protocol Independent Multicast - Sparse Mode" Join message sent by
   a given node identifies one or more multicast distribution trees that
   that node wishes to join.  Each tree is identified by the combination
   of a multicast group address and a source address (where the source
   address is possibly a "wild card").  Under certain conditions it can
   be useful, when joining a tree, to specify additional information
   related to the construction of the tree.  However, there has been no
   way to do so until now.  This document describes a modification of
   the Join message that allows a node to associate attributes with a
   particular tree.  The attributes are encoded in Type-Length-Value
   format.

Boers, et al.               Standards Track                     [Page 1]
RFC 5384                   PIM Join Attribute              November 2008

Table of Contents

   1. Introduction ....................................................2
   2. Specification of Requirements ...................................3
   3. Use of Join Attributes ..........................................3
      3.1. Sending Join Attributes ....................................3
      3.2. The Join Attribute Option in the PIM Hello .................4
      3.3. Receiving Join Attributes ..................................4
           3.3.1. General Considerations ..............................4
           3.3.2. Transitive and Non-Transitive Attributes ............5
           3.3.3. Conflicting Attributes ..............................5
           3.3.4. Attribute Change ....................................6
      3.4. PIM Attribute Packet Format ................................7
           3.4.1. PIM Join Packet Format ..............................7
           3.4.2. PIM Join Attribute Hello Option .....................8
   4. IANA Considerations .............................................8
   5. Security Considerations .........................................9
   6. Acknowledgments .................................................9
   7. Normative References ............................................9
   8. Informative References ..........................................9

1.  Introduction

   In the protocol known as "Protocol Independent Multicast - Sparse
   Mode" [RFC4601] (henceforth referred to as "PIM"), a Join message
   sent by a given node may identify one or more multicast distribution
   trees that that node wishes to join.  Each tree is identified by the
   combination of a multicast group address and a source address (where
   the source address is possibly a "wild card").  Under certain
   conditions it can be useful, when joining a tree, to specify
   additional information related to the construction of the tree.
   However, there has been no way to do so until now.  This document
   describes a modification of the Join message that allows a node to
   associate an attribute, encoded in Type-Length-Value (TLV) format,
   with a particular tree that it wishes to join.  These attributes are
   known as "PIM Join Attributes".

   In the PIM Join message, the Source Address is identified by being
   encoded as an "Encoded-Source Address" ([RFC4601], section 4.9.1).
   Each Encoded-Source Address occurs in the context of a particular
   group address, represented as an "Encoded-Group Address".  Together,
   the Encoded-Source Address and the Encoded-Group Address identify a
   multicast distribution tree.  The Encoded-Source Address contains an
   "encoding type" field.  The only value defined in [RFC4601] is 0.
   This specification is the first to assign another encoding type
   value.

Boers, et al.               Standards Track                     [Page 2]