All things related to multicast

[Nitin jain <>]

Hi Lucy,

   I am curious why turning off the IGMP snooping should not work in every
case. If that doesn't work, we should examine the case as the plain layer2
switch/hub would also exhibit the same issue. 

I would think that this would be the case for any vendor that is not aware
of IGMPv3 in the snooping implementation as IGMPv2 did not care about the
source specificness. Therefore, plain layer2 forwarding would not be
adequate for source specific joins, or exclude source. Thus, it would be
advisable not to turn on any Layer 2 specific snooping, be it CGMP, IGMP
etc. if the implementation is unaware of IGMPv3.

Please elaborate the case that would break. Thanks.

Nitin

At 01:28 PM 6/27/02 -0700, Lucy E. Lynch wrote:
>All -
>
>As you may already know, we've uncovered a problem with IGMPv3 and HP
>4000m series switches. The condensed version is that in order to use
>SSM/IGMPv3 on a sub-net with an HP 4000 in the path IGMP snooping MUST be
>turned off in the switch.
>
>see:
>http://archives.internet2.edu/guest/archives/wg-multicast/log200206/msg0003
8.html
>
>José Domínguez, our senior network engineer here at the UO, has tried to
>pursue this with HP but the results are a bit frustrating. HP is
>discontinuing the 4000 series switches by early next year and has no plans
>to address IGPMv3 related problems since there is not an IETF RFC for same
>(their proposed solution is to upgrade to new gear). We've turned off
>snooping on at least one switch here to deal with testing issues - but
>this isn't a solution that will work for everyone. If you have similar
>issues on your campus - or if you own HP gear, please contact me as we
>would like to be able to escalate this issue with HP and more is better...
>
>Lucy E. Lynch                          Academic User Services
>Computing Center                       University of Oregon
>
>               (541) 346-1774/Cell: 912-7998
>