Multicast-Scope Zone Announcement Protocol (MZAP)
RFC 2776
Network Working Group M. Handley
Request for Comments: 2776 ACIRI
Category: Standards Track D. Thaler
Microsoft
R. Kermode
Motorola
February 2000
Multicast-Scope Zone Announcement Protocol (MZAP)
Status of this Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2000). All Rights Reserved.
Abstract
This document defines a protocol, the Multicast-Scope Zone
Announcement Protocol (MZAP), for discovering the multicast
administrative scope zones that are relevant at a particular
location. MZAP also provides mechanisms whereby common
misconfigurations of administrative scope zones can be discovered.
Table of Contents
1 Introduction ................................................ 2
2 Terminology ................................................. 4
3 Overview .................................................... 5
3.1 Scope Nesting ............................................. 6
3.2 Other Messages ............................................ 7
3.3 Zone IDs .................................................. 7
4 Detecting Router Misconfigurations .......................... 8
4.1 Detecting non-convex scope zones .......................... 8
4.2 Detecting leaky boundaries for non-local scopes ........... 9
4.3 Detecting a leaky Local Scope zone ........................ 10
4.4 Detecting conflicting scope zones ......................... 10
5 Packet Formats .............................................. 11
5.1 Zone Announcement Message ................................. 14
5.2 Zone Limit Exceeded (ZLE) ................................. 15
5.3 Zone Convexity Message .................................... 15
Handley, et al. Standards Track [Page 1]
RFC 2776 MZAP February 2000
5.4 Not-Inside Message ........................................ 16
6 Message Processing Rules .................................... 17
6.1 Internal entities listening to MZAP messages .............. 17
6.2 Sending ZAMs .............................................. 18
6.3 Receiving ZAMs ............................................ 18
6.4 Sending ZLEs .............................................. 20
6.5 Receiving ZLEs ............................................ 20
6.6 Sending ZCMs .............................................. 21
6.7 Receiving ZCMs ............................................ 21
6.8 Sending NIMs .............................................. 21
6.9 Receiving NIMs ............................................ 22
7 Constants ................................................... 22
8 Security Considerations ..................................... 23
9 Acknowledgements ............................................ 24
10 References ................................................. 25
11 Authors' Addresses ......................................... 26
12 Full Copyright Statement ................................... 27
1. Introduction
The use of administratively-scoped IP multicast, as defined in RFC
2365 [1], allows packets to be addressed to a specific range of
multicast addresses (e.g., 239.0.0.0 to 239.255.255.255 for IPv4)
such that the packets will not cross configured administrative
boundaries, and also allows such addresses to be locally assigned and
hence are not required to be unique across administrative boundaries.
This property of logical naming both allows for address reuse, as
well as provides the capability for infrastructure services such as
address allocation, session advertisement, and service location to
use well-known addresses which are guaranteed to have local
significance within every organization.
The range of administratively-scoped addresses can be subdivided by
administrators so that multiple levels of administrative boundaries
can be simultaneously supported. As a result, a "multicast scope" is
defined as a particular range of addresses which has been given some
topological meaning.
To support such usage, a router at an administrative boundary is
configured with one or more per-interface filters, or "multicast
scope boundaries". Having such a boundary on an interface means that
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