Subject: WG Last Call: IGMP Version 3 to Proposed Standard

From: Bill Fenner <[email-masked]>
Date: Wed, 12 Jul 2000 15:44:14 -0700

Dear IDMR WG,

  This is a 2 week Working Group Last Call for IGMP Version 3,
draft-ietf-idmr-igmp-v3-04.txt, to Proposed Standard.

	Title		: Internet Group Management Protocol, Version 3
	Author(s)	: B. Cain, S. Deering, I. Kouvelas, A. Thyagarajan 
	Filename	: draft-ietf-idmr-igmp-v3-04.txt
	Pages		: 44
	Date		: 05-Jun-00

	This document specifies Version 3 of the Internet Group Management
	Protocol, IGMPv3.  IGMP is the protocol used by IPv4 systems
	to report their IP multicast group memberships to neighboring
	multicast routers.  Version 3 of IGMP adds support for 'source
	filtering', that is, the ability for a system to report interest
	in receiving packets *only* from specific source addresses, or
	from *all but* specific source addresses, sent to a particular
	multicast address.  That information may be used by multicast
	routing protocols to avoid delivering multicast packets from
	specific sources to networks where there are no interested
	receivers.

  Please comment by Wednesday, July 26, 2000, on the IDMR mailing list
<[email-masked]> or directly to working group chair,
<[email-masked]>.

Thanks,
  Bill

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From: Beau Williamson <[email-masked]>
Date: Fri, 14 Jul 2000 09:27:20 -0700

Bill, et al,

I've seen a great deal of discussion about how the host and the router will make use of IGMPv3 and the impacts on their operation.  However, has anyone done much work as to what impact these new mechanisms will have on switches that perform IGMP Snooping in order to constrain multicast flows at Layer 2?

I personally have not had the time to give this much thought although it does appear on the surface (at least it does to me) that IGMPv3 will have a *significant* impact on switches that are doing IGMP Snooping.  Maybe there are others in the WG that have given thought to this and can comment as to the foreseen impact.

Beau

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From: Michael Vorburger <[email-masked]>
Date: Fri, 14 Jul 2000 11:06:32 -0700

Beau,

I am a DE working on CatOS for MMLS and IGMP Snooping under Ramana.  We
have implemented a sort of "IGMPv3 minimal-support" for IGMP Snooping on
Cat5k/6k that will be part of the upcoming CatOS 6.1 ORL sw release. 
Our approach is documented in
http://wwwin-people.cisco.com/rmellach-group/mcast/igmpv3.html

This is a very simplistic first approach, later optimisations are to be
seen and are proposed in the above document.  We are ignoring the source
specific portion of v3 reports at this first phase, and able to process
joins essentially as if they were v2 joins.  The main issue we faced
while thinking about this issue are the LEAVES; in order to remove ports
for constraining multicast flows at Layer 2 when a host signals
disinterest IGMP snooping would have to either keep a complete source
list per host/per port/per group, or play more extensive IGMP Querier
functionality.  It would have been a lot easier for us if the IGMPv3
reports always contained a FULL include or exclude source list, not just
partial diffs, but I am assuming it is ways to late to change anything
in that respect.

I am assuming we will eventually refine this first simplistic IGMPv3
Support in IGMP Snooping for full-fledged support.  This first approach
is simply to ensure we don't completely break multicast; we understand
people were disabling IGMP Snooping (and thus MMLS) to test IGMPv3... ;)

Thanks,
Michael

-- 

Thank you,
  Michael

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From: Naga Chandika <[email-masked]>
Date: Fri, 14 Jul 2000 09:38:11 -0700

Hi Beau,

We are already implementing minimal support for IGMPV3 snooping in
catalyst switches (hybrid versions) so that IGMP snooping does not break
IGMPV3.  We will also have full support for IGMPV3 Snooping in the near
future.

Thanks
Naga
-- 
Naga Chandika
Cisco Systems, Inc.
Ph:(408)527-9579 (w)