All things related to multicast

[Bob Riddle <>]

The problem I experienced when WinXP only supported IGMPv3 involved an 
edge router that supported IGMPv3 and a switch that did not support 
IGMPv3.  This allowed the WinXP machine to "join" the multicast stream 
but the switch threw away all the "keep-alive" messages from the 
router.  As long as you only needed to watch a few minutes of the 
multicast stream, everything worked fine   :-) .

When I set up a linux machine using IGMPv2 to listen to the stream on 
that switch, it "kept alive" the stream.   Lots of weird debugging 
involved, so good luck!

Stig Venaas wrote:
> Nicholas J Humfrey wrote:
> > Yes, I wasn't expecting this behaviour, but it certainly seems to 
> > happen. Could this be a known Cisco bug? Does it keep group 
> > membership state in a single table or multiple tables for each IGMP 
> > version?
>
> At least I haven't seen any such issues with Cisco. Rather than guessing
> where the bug might be, try to do some debugging. First thing I would do
> is tcpdump/wireshark to see which IGMP messages each of the hosts
> receive and send, also check the IGMP state on the router for the
> relevant groups, and if possible the IGMP state on the host for that
> group. I don't know how much info you can get out of Mac OS X and
> Vista...
>
> Stig

--
Bob Riddle (bdr @ umich.edu)            Enabling Technologies
University of Michigan Medical School   1301 Catherine Street
M4101 MSB1 - 6024                       Ann Arbor, Michigan  48109-0624

"Math illiteracy affects 7 out of every 5 people"