Automatic Multicast Tunneling
RFC 7450

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Internet Engineering Task Force (IETF)                     G. Bumgardner
Request for Comments: 7450                                 February 2015
Category: Standards Track
ISSN: 2070-1721

                     Automatic Multicast Tunneling

Abstract

   This document describes Automatic Multicast Tunneling (AMT), a
   protocol for delivering multicast traffic from sources in a
   multicast-enabled network to receivers that lack multicast
   connectivity to the source network.  The protocol uses UDP
   encapsulation and unicast replication to provide this functionality.

   The AMT protocol is specifically designed to support rapid deployment
   by requiring minimal changes to existing network infrastructure.

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/rfc7450.

Copyright Notice

   Copyright (c) 2015 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.  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.

Bumgardner                   Standards Track                    [Page 1]
RFC 7450                           AMT                     February 2015

Table of Contents

   1. Introduction ....................................................3
   2. Applicability ...................................................3
   3. Terminology .....................................................4
      3.1. Requirements Notation ......................................4
      3.2. Definitions ................................................4
      3.3. Abbreviations ..............................................5
   4. Protocol Overview ...............................................6
      4.1. General Architecture .......................................6
           4.1.1. Relationship to IGMP and MLD Protocols ..............6
           4.1.2. Gateways ............................................7
           4.1.3. Relays .............................................10
           4.1.4. Deployment .........................................13
           4.1.5. Discovery ..........................................14
      4.2. General Operation .........................................15
           4.2.1. Message Sequences ..................................15
           4.2.2. Tunneling ..........................................26
   5. Protocol Description ...........................................31
      5.1. Protocol Messages .........................................31
           5.1.1. Relay Discovery ....................................31
           5.1.2. Relay Advertisement ................................32
           5.1.3. Request ............................................34
           5.1.4. Membership Query ...................................35
           5.1.5. Membership Update ..................................39
           5.1.6. Multicast Data .....................................41
           5.1.7. Teardown ...........................................43
      5.2. Gateway Operation .........................................45
           5.2.1. IP/IGMP/MLD Protocol Requirements ..................45
           5.2.2. Pseudo-Interface Configuration .....................47
           5.2.3. Gateway Service ....................................48
      5.3. Relay Operation ...........................................61
           5.3.1. IP/IGMP/MLD Protocol Requirements ..................61
           5.3.2. Startup ............................................61
           5.3.3. Running ............................................62
           5.3.4. Shutdown ...........................................73
           5.3.5. Response MAC Generation ............................73
           5.3.6. Private Secret Generation ..........................74
   6. Security Considerations ........................................74
      6.1. Relays ....................................................74
      6.2. Gateways ..................................................76