Subject: IGMPv3 interoperability question

From: [email-masked]
Date: Thu, 3 May 2001 19:25:50 -0700

Hi all,

     I have a question about IGMP interoperability in the following scenario.
An IGMPv3 querier, an IGMPv1 host, an IGMPv2 host, and an IGMPv3 host are in the
same IP subnet.  Suppose these three hosts all join the same group G.  So the
IGMPv3 querier will have Group Compatibility Mode = IGMPv1 for group G and will
ignore IGMPv2 leave message for G.  How about Group Record for G in IGMPv3
reports?  Will the querier simply ignore the Group Record or will it convert the
record into an equivalent IGMPv1 report?   If the answer is the latter, is it
O.K. to treat any Group Record for G in IGMPv3 report as a join for G?

How about another scenario where the Group Compatability Mode for group G =
IGMPv2?  In this case, how will the querier handle Group Record for G in IGMPv3
reports?

Thanks,
-- James Huang