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Cisco Systems Router-port Group Management Protocol (RGMP) (RFC3488)

IP.com Disclosure Number: IPCOM000011550D
Original Publication Date: 2003-Feb-01
Included in the Prior Art Database: 2003-Mar-04
Document File: 18 page(s) / 37K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

I. Wu: AUTHOR [+2]

Abstract

This document describes the Router-port Group Management Protocol (RGMP). This protocol was developed by Cisco Systems and is used between multicast routers and switches to restrict multicast packet forwarding in switches to those routers where the packets may be needed.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 8% of the total text.

Network Working Group                                              I. Wu

Request for Comments: 3488                                     T. Eckert

Category: Informational                                    Cisco Systems

                                                           February 2003

                             Cisco Systems

              Router-port Group Management Protocol (RGMP)

Status of this Memo

   This memo provides information for the Internet community.  It does

   not specify an Internet standard of any kind.  Distribution of this

   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

Abstract

   This document describes the Router-port Group Management Protocol

   (RGMP).  This protocol was developed by Cisco Systems and is used

   between multicast routers and switches to restrict multicast packet

   forwarding in switches to those routers where the packets may be

   needed.

   RGMP is designed for backbone switched networks where multiple, high

   speed routers are interconnected.

1. Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",

   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this

   document are to be interpreted as described in BCP 14, RFC 2119 [2].

2. Introduction

   IGMP Snooping is a popular, but not well documented mechanism to

   restrict multicast traffic, in switched networks, to those ports that

   want to receive the multicast traffic.  It dynamically establishes

   and terminates multicast group specific forwarding in switches that

   support this feature.

Wu & Eckert                  Informational                      [Page 1]

RFC 3488                  Cisco Systems RGMP               February 2003

   The main limitation of IGMP Snooping is that it can only restrict

   multicast traffic onto switch ports where receiving hosts are

   connected directly or indirectly via other switches.  IGMP Snooping

   can not restrict multicast traffic to ports where at least one

   multicast router is connected.  It must instead flood multicast

   traffic to these ports.  Snooping on IGMP messages alone is an

   intrinsic limitation.  Through it, a switch can only learn which

   multicast flows are being requested by hosts.  A switch can not learn

   through IGMP which traffic flows need to be received by router ports

   to be routed because routers do not report these flows via IGMP.

   In situations where multiple multicast routers are connected to a

   switched backbone, IGMP Snooping will not reduce multicast traffic

   load.  Nor will it assist in increasing internal bandwidth through

   th...