Re: [ssm] Document Action: An Overview of Source-SpecificMulticast(SSM) Deployment to Informational

[Hitoshi Asaeda <Hitoshi.Asaeda@sophia.inria.fr>]

> > From my experience, windows XP does send IGMPv2 reports if it sees IGMPv2 
> > queries.
> >It MUST do this according to the IGMPv3 spec.
> 
> So if I do manage to get my LAN completely IGMPv3 capable and thus allow 
> the use of SSM, all it takes is one person
> plugging in a machine running IGMPv2 and SSM breaks.  This probably means 
> that SSM is unimplementable except
> in some special cases (example: one host per vlan).

In fact, and unfortunately, you are right.
There was some lack of important statements in IGMPv3.

One is a following sentence:
	"the Querier continues to send IGMPv3 queries, regardless of
	 its Multicast Address Compatibility Mode."
This should be included in the RFC. But it was too late. Actually,
since we've found the problem before the MLDv2's last-call, it is
included in Sect.8.3.2 of draft-vida-mld-v2-07.txt, though.

Other is something related to "host compatibility mode" which I post
the problem in MAGMA ML.
<http://www1.ietf.org/mail-archive/working-groups/magma/current/msg00027.html>
But I heard this mail was also too late. Yes, it is also included in
MLDv2's I-D (Sect.10.1) as follows:
	"A forged Version 1 Query message will put MLDv2 listeners on
	 that link in MLDv1 Host Compatibility Mode.  This scenario
	 can be avoided by providing MLDv2 hosts with a configuration
	 option to ignore Version 1 messages completely."

FYI, my IGMPv3/MLDv2 implementations (incl. KAME) support them, anyway.
--
Hitoshi Asaeda

p.s. "IGMPv3 addendum" is the solution?
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