[pve-devel] corosync, multicast problem because of vmbr multicast_snooping enabled

Alexandre DERUMIER aderumier at odiso.com
Sun Mar 10 08:29:59 CET 2013

>>@alexandre: What precise Cisco switch do you see the problems with? 
>>What IOS version? Are there any firmware upgrade available? 

cisco 2960g && cisco 6500. (can't remember ios version but version of 2012 for both)

My biggest problem was 2 week ago, I shutdown 1 of my nodes, and after 2min, alls nodes on the same vlan
(including differents cluster with differents multicast address) can't see each others.
disabling igmp on linux bridge has resolved the problem.
So it should be related to snooping & igmp queries, but I don't known if the problem is on physical switch or linux bridge.

I'll try to reproduce the problem this week and will do some tcpdump to find the problem

Now, I see a lot of bug reports on the net about snooping on linux bridge. (don't known if it's about snooping or igmp queries).

And I trust more my good old cisco switchs than a 2 year old implementation on linux bridge.

here another bug with igmp report from bridge and bonding, if failover occur in bonding, igmp report are not send anymore :/

----- Mail original ----- 

De: "Michael Rasmussen" <mir at datanom.net> 
À: pve-devel at pve.proxmox.com 
Envoyé: Samedi 9 Mars 2013 21:22:27 
Objet: Re: [pve-devel] corosync, multicast problem because of vmbr multicast_snooping enabled 

On Sat, 9 Mar 2013 18:33:58 +0000 
Dietmar Maurer <dietmar at proxmox.com> wrote: 

> So I think we talk about switch bugs here, not normal behavior. 
I am leaning towards the same conclusion since I have never seen 
those queries cause any problems here. 

@alexandre: What precise Cisco switch do you see the problems with? 
What IOS version? Are there any firmware upgrade available? 

According to Cisco the queries should not cause any problems but maybe 
this is what causes your problems: 

"Multicast routers send host-query messages periodically to refresh 
their knowledge of memberships present on their networks. If, after 
some number of queries, the Cisco IOS software discovers that no local 
hosts are members of a multicast group, the software stops forwarding 
onto the local network multicast packets from remote origins for that 
group and sends a prune message upstream toward the source." 


Michael Rasmussen 

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