RFC 2365 (rfc2365) - Page 1 of 8
Administratively Scoped IP Multicast
Alternative Format: Original Text Document
Network Working Group D. Meyer
Request for Comments: 2365 University of Oregon
BCP: 23 July 1998
Category: Best Current Practice
Administratively Scoped IP Multicast
Status of this Memo
This document specifies an Internet Best Current Practices for the
Internet Community, and requests discussion and suggestions for
improvements. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (1998). All Rights Reserved.
1. Abstract
This document defines the "administratively scoped IPv4 multicast
space" to be the range 239.0.0.0 to 239.255.255.255. In addition, it
describes a simple set of semantics for the implementation of
Administratively Scoped IP Multicast. Finally, it provides a mapping
between the IPv6 multicast address classes [RFC 1884] and IPv4
multicast address classes.
This memo is a product of the MBONE Deployment Working Group (MBONED)
in the Operations and Management Area of the Internet Engineering
Task Force. Submit comments to [email protected]> or the author.
2. Acknowledgments
Much of this memo is taken from "Administratively Scoped IP
Multicast", Van Jacobson and Steve Deering, presented at the 30th
IETF, Toronto, Canada, 25 July 1994. Steve Casner, Mark Handley and
Dave Thaler have also provided insightful comments on earlier
versions of this document.
3. Introduction
Most current IP multicast implementations achieve some level of
scoping by using the TTL field in the IP header. Typical MBONE
(Multicast Backbone) usage has been to engineer TTL thresholds that
confine traffic to some administratively defined topological region.
The basic forwarding rule for interfaces with configured TTL
thresholds is that a packet is not forwarded across the interface
unless its remaining TTL is greater than the threshold.
Meyer Best Current Practice