PIM Working Group H. Asaeda
Internet-Draft NICT
Intended status: Standards Track December 3, 2013
Expires: June 6, 2014
IGMP/MLD-Based Explicit Membership Tracking Function for Multicast
Routers
draft-ietf-pim-explicit-tracking-09
Abstract
This document describes the IGMP/MLD-based explicit membership
tracking function for multicast routers and IGMP/MLD proxy devices
supporting IGMPv3/MLDv2. The explicit membership tracking function
contributes to saving network resources and shortening leave latency.
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Asaeda Expires June 6, 2014 [Page 1]Internet-Draft Explicit Membership Tracking Function December 2013Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Membership State Information . . . . . . . . . . . . . . . . 4
4. Specific Query Suppression . . . . . . . . . . . . . . . . . 4
5. Shortening Leave Latency . . . . . . . . . . . . . . . . . . 6
6. Risk of Wrong Membership State . . . . . . . . . . . . . . . 6
7. All-Zero and Unspecified Source Addresses . . . . . . . . . . 7
8. Compatibility with Older Version Protocols . . . . . . . . . 8
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
10. Security Considerations . . . . . . . . . . . . . . . . . . . 8
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
12.1. Normative References . . . . . . . . . . . . . . . . . . 9
12.2. Informative References . . . . . . . . . . . . . . . . . 9
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
The Internet Group Management Protocol (IGMP) version 3 [2] for IPv4
and the Multicast Listener Discovery Protocol (MLD) version 2 [3] for
IPv6 are the standard protocols used by member hosts and multicast
routers. Lightweight IGMPv3 and Lightweight MLDv2 (or LW-IGMPv3 and
LW-MLDv2) [4] are subsets of the standard IGMPv3 and MLDv2.
When a host starts/finishes listening to particular multicast
channels, it sends IGMP/MLD State-Change Report messages specifying
the corresponding channel information as the join/leave request to
its upstream router (i.e., an adjacent multicast router or IGMP/MLD
proxy device [8]). The "unsolicited" report messages are sent only
when the host joins/leaves the channels. Since IGMP/MLD are non-
reliable protocols, unsolicited report messages may be lost or may
not reach upstream routers. To alleviate this problem, unsolicited
report messages are retransmitted a number of times according to the
value of the [Robustness Variable] defined in [2][3].
Also, a querier router periodically sends IGMP/MLD General Query
messages every General Query timer interval (i.e. [Query Interval]
value defined in [2][3]). Upon receiving the query messages, the
member hosts reply with "solicited" report messages. Routers then
keep their membership state information up to date. However, this
approach still does not guarantee that the membership state is always
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