[Pacemaker] Configuring multicast on Extreme Networks switches

Phil Frost phil at macprofessionals.com
Sat Mar 17 08:27:43 EDT 2012

I'm experiencing some problems with pacemaker where everything works fine, unless I wait a few minutes after starting corosync. Then, most things I've tried (adding resources, stopping pacemaker...) fail, and syslog is flooded with "retransmit list" errors, several per second.

I think the problem is that my switch (an Extreme Networks Summit X460) is doing IGMP snooping, and the entries are expiring. I understand the concept of IGMP snooping well enough; what I don't understand is why the entries aren't being renewed. I've never had to configure multicast, so I'm guessing, but I suppose there isn't anything issuing IGMP queries, so the snooping entries never get updated beyond the initial join. I'm not entirely sure what that thing (the thing that should be issuing queries) is, or how I get one.

I know this isn't strictly a Pacemaker issue - I'm just hoping someone can point me in the right direction. I know there was an FAQ entry somewhere about how to configure Cisco to work, but I can't find that. There is plenty of information I've found about configuring mulitcast routers, but mostly nothing about getting multicast to work in the simple case of a single VLAN. I know I could just disable IGMP snooping, but I'd rather know how to do the Right Thing. Any pointers would be appreciated.

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