PIM Message Type Space Extension and Reserved Bits
RFC 8736

Document Type RFC - Proposed Standard (February 2020; No errata)
Obsoletes RFC 6166
Last updated 2020-02-29
Replaces draft-venaas-pim-reserved-bits
Stream IETF
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Reviews
Stream WG state Submitted to IESG for Publication
Document shepherd Mike McBride
Shepherd write-up Show (last changed 2019-08-07)
IESG IESG state RFC 8736 (Proposed Standard)
Consensus Boilerplate Yes
Telechat date
Responsible AD Deborah Brungard
Send notices to Mike McBride <mmcbride7@gmail.com>
IANA IANA review state Version Changed - Review Needed
IANA action state RFC-Ed-Ack


Internet Engineering Task Force (IETF)                         S. Venaas
Request for Comments: 8736                           Cisco Systems, Inc.
Obsoletes: 6166                                                A. Retana
Updates: 3973, 5015, 5059, 6754, 7761,      Futurewei Technologies, Inc.
         8364                                              February 2020
Category: Standards Track                                               
ISSN: 2070-1721

           PIM Message Type Space Extension and Reserved Bits

Abstract

   The PIM version 2 messages share a common message header format.  The
   common header definition contains eight reserved bits.  This document
   specifies how these bits may be used by individual message types and
   creates a registry containing the per-message-type usage.  This
   document also extends the PIM type space by defining three new
   message types.  For each of the new types, four of the previously
   reserved bits are used to form an extended type range.

   This document updates RFCs 7761 and 3973 by defining the use of the
   currently Reserved field in the PIM common header.  This document
   further updates RFCs 7761 and 3973, along with RFCs 5015, 5059, 6754,
   and 8364, by specifying the use of the currently reserved bits for
   each PIM message.

   This document obsoletes RFC 6166.

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 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc8736.

Copyright Notice

   Copyright (c) 2020 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
   (https://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.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction
   2.  Conventions Used in This Document
   3.  PIM Header Common Format
   4.  Flag Bit Definitions
     4.1.  Flag Bits for Type 4 (Bootstrap)
     4.2.  Flag Bits for Type 10 (DF Election)
     4.3.  Flag Bits for Type 12 (PFM)
     4.4.  Flag Bits for Types 13, 14, and 15 (Type Space Extension)
   5.  PIM Type Space Extension
   6.  Security Considerations
   7.  IANA Considerations
   8.  References
     8.1.  Normative References
     8.2.  Informative References
   Authors' Addresses

1.  Introduction

   The PIM version 2 messages share a common message header format
   defined in the PIM Sparse Mode specification [RFC7761].  The common
   header definition contains eight reserved bits.  While all message
   types use this common header, there is no document formally
   specifying that these bits are to be used per message type.

   This document refers to the bits specified as "reserved" in the
   common PIM header [RFC7761] as "PIM message type Flag Bits" or,
   simply, "Flag Bits", and it specifies that they are to be separately
   used on a per-message-type basis.  It creates a registry containing
   the per-message-type usage.

   This document updates [RFC7761] and [RFC3973] by defining the use of
   the currently Reserved field in the PIM common header.  This document
   further updates [RFC7761] and [RFC3973], along with [RFC5015],
   [RFC5059], [RFC6754], and [RFC8364], by specifying the use of the
   currently reserved bits for each PIM message.

   The currently defined PIM message types are in the range from 0 to
   15.  That type space is almost exhausted.  Message type 15 was
   reserved by [RFC6166] for type space extension.  In Section 5, this
   document specifies the use of the Flag Bits for message types 13, 14,
   and 15 in order to extend the PIM type space.  This document
   obsoletes [RFC6166].

2.  Conventions Used in This Document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

3.  PIM Header Common Format

   The common PIM header is defined in Section 4.9 of [RFC7761].  This
   document updates the definition of the Reserved field and refers to
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