Overview of the Internet Multicast Addressing Architecture
RFC 6308

Internet Engineering Task Force (IETF)                         P. Savola
Request for Comments: 6308                                     CSC/FUNET
Obsoletes: 2908                                                June 2011
Category: Informational
ISSN: 2070-1721

       Overview of the Internet Multicast Addressing Architecture

Abstract

   The lack of up-to-date documentation on IP multicast address
   allocation and assignment procedures has caused a great deal of
   confusion.  To clarify the situation, this memo describes the
   allocation and assignment techniques and mechanisms currently (as of
   this writing) in use.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   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/rfc6308.

Copyright Notice

   Copyright (c) 2011 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.

Savola                        Informational                     [Page 1]
RFC 6308              Multicast Address Allocation             June 2011

Table of Contents

   1. Introduction ....................................................2
      1.1. Terminology: Allocation or Assignment ......................3
   2. Multicast Address Allocation ....................................3
      2.1. Derived Allocation .........................................3
           2.1.1. GLOP Allocation .....................................4
           2.1.2. Unicast-Prefix-Based Allocation .....................4
      2.2. Administratively Scoped Allocation .........................5
      2.3. Static IANA Allocation .....................................6
      2.4. Dynamic Allocation .........................................6
   3. Multicast Address Assignment ....................................6
      3.1. Derived Assignment .........................................6
      3.2. SSM Assignment inside the Node .............................7
      3.3. Manually Configured Assignment .............................7
      3.4. Static IANA Assignment .....................................7
           3.4.1. Global IANA Assignment ..............................7
           3.4.2. Scope-Relative IANA Assignment ......................8
      3.5. Dynamic Assignments ........................................8
   4. Summary and Future Directions ...................................9
      4.1. Prefix Allocation ..........................................9
      4.2. Address Assignment ........................................10
      4.3. Future Actions ............................................11
   5. Acknowledgements ...............................................11
   6. IANA Considerations ............................................11
   7. Security Considerations ........................................11
   8. References .....................................................12
      8.1. Normative References ......................................12
      8.2. Informative References ....................................13

1.  Introduction

   Good, up-to-date documentation of IP multicast is close to
   non-existent.  Particularly, this is an issue with multicast address
   allocations (to networks and sites) and assignments (to hosts and
   applications).  This problem is stressed by the fact that there
   exists confusing or misleading documentation on the subject
   [RFC2908].  The consequence is that those who wish to learn about IP
   multicast and how the addressing works do not get a clear view of the
   current situation.

   The aim of this document is to provide a brief overview of multicast
   addressing and allocation techniques.  The term "addressing
   architecture" refers to the set of addressing mechanisms and methods