Population Count Extensions to Protocol Independent Multicast (PIM)
RFC 6807

Internet Engineering Task Force (IETF)                      D. Farinacci
Request for Comments: 6807                                   G. Shepherd
Category: Experimental                                         S. Venaas
ISSN: 2070-1721                                            Cisco Systems
                                                                  Y. Cai
                                                               Microsoft
                                                           December 2012

  Population Count Extensions to Protocol Independent Multicast (PIM)

Abstract

   This specification defines a method for providing multicast
   distribution-tree accounting data.  Simple extensions to the Protocol
   Independent Multicast (PIM) protocol allow a rough approximation of
   tree-based data in a scalable fashion.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for examination, experimental implementation, and
   evaluation.

   This document defines an Experimental Protocol for the Internet
   community.  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).  Not
   all documents approved by the IESG are a candidate for any level of
   Internet Standard; see 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/rfc6807.

Farinacci, et al.             Experimental                      [Page 1]
RFC 6807           Population Count Extensions to PIM      December 2012

Copyright Notice

   Copyright (c) 2012 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
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Requirements Notation  . . . . . . . . . . . . . . . . . .  4
     1.2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Pop-Count-Supported Hello Option . . . . . . . . . . . . . . .  4
   3.  New Pop-Count Join Attribute Format  . . . . . . . . . . . . .  5
     3.1.  Options  . . . . . . . . . . . . . . . . . . . . . . . . .  8
       3.1.1.  Link Speed Encoding  . . . . . . . . . . . . . . . . . 10
     3.2.  Example Message Layouts  . . . . . . . . . . . . . . . . . 10
   4.  How to Use Pop-Count Encoding  . . . . . . . . . . . . . . . . 11
   5.  Implementation Approaches  . . . . . . . . . . . . . . . . . . 12
   6.  Caveats  . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
   7.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 13
   8.  Security Considerations  . . . . . . . . . . . . . . . . . . . 13
   9.  Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 14
   10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
     10.1. Normative References . . . . . . . . . . . . . . . . . . . 14
     10.2. Informative References . . . . . . . . . . . . . . . . . . 14

Farinacci, et al.             Experimental                      [Page 2]
RFC 6807           Population Count Extensions to PIM      December 2012

1.  Introduction

   This document specifies a mechanism to convey accounting information
   using the Protocol Independent Multicast (PIM) protocol [RFC4601]
   [RFC5015].  Putting the mechanism in PIM allows efficient
   distribution and maintenance of such accounting information.
   Previous mechanisms require data to be correlated from multiple
   router sources.

   This mechanism allows a single router to be queried to obtain
   accounting and statistic information for a multicast distribution
   tree as a whole or any distribution sub-tree downstream from a
   queried router.  The amount of information is fixed and does not
   increase as multicast membership, tree diameter, or branching
   increases.

   The sort of accounting data this specification provides, on a per-
   multicast-route basis, are:

   1.  The number of branches in a distribution tree.