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RedHat Enterprise Cluster and Cisco IGMP Snooping/Querying


Has anyone else had any experience with IGMP Snooping/Querying and RedHat Enterprise Cluster?

We have been experiencing a large amount of problems with this functionality.

We are running IGMP Querying in our environment and we recently set up a second querier. 
Here's the steps we took

Existing querier:

Everything was running fine.

Added a new querier on a different switch:

At this point, all of our RedHat Enterprise Clusters fenced themselves and needed to be restarted in order to restore
access.  In order to restart the RedHat Enterprise Clusters, the physical servers must be rebooted.

Are there any known issues with RedHat Enterprise Clustering and Cisco Switches (3750
series)?  I would expect the querier change to be seamless, but it does not seem that this 

is the case. 

5 Replies 5


Hi Eric,

I was wondering if you got your red hat clustering working on your nexus boxes? If so can you explain briefly how you did it. We can run it no problem on a 3750 stacked environment but the nexus/fex's are giving us some issues.




Actually - yes - we had the same problem in our Nexus environment and ultimately resolved it.  Here's what you need to do:

vlan x

ip igmp snooping querier x.x.x.x

  no ip igmp snooping link-local-groups-suppression

(you can give it any IP address you want)
We were not able to get our clusters to come up UNTIL we enabled these commands
Hope this helps.

There is bug in older code for this.

5.0(3)N1(1) and later has fix for this


I don't think the "no ip igmp snooping link-local-groups-suppression" is needed unless the multicast address is in the subnet.

On newer code the snooping querier has to be configured under "vlan configuration x", not "vlan x".  The querier should be the IP of the vlan interface and can be configured on multiple switches for redundancy.  The lowest IP is the active one.


In our organizaiton we have Red Hat Cluster with 2 cisco switch (Model: cisco WS-C2960S-24TD-L, Version: "flash:/ c2960s-universalk9-mz.122-55.SE3/c2960s-universalk9-mz.122-55.SE3.bin").

- We are using HP Chassis c7000 and Server is on the chassis. There are 2 service IC & Med. Each server has one service primary and other secondary running.

- The two cluster switches are connected each other with Ether channer trunk (1+1) link. Also these 2 switches are connected to our Mgmt switch for Server Admin access to HP Chassis via OA port. The Red Hat system has cluster lan (pri & sec) & OA lan (01 & 02 of HP chassis) connected to Cluster switches. The Mgmt VLAN is 501 -


When the CluserSW01 goes down the cluser shifted to CluseterSW02 with Cluser_Secondary_LAN and OA2. But when the ClusterSW01 switch comes again than the communication breaks and cluster don come up.

I was thinking this is either STP or IGMP, well sure though. As these are production systems hence we also couldn't do much more test as well.

If you have face any such issue or have experience with it or know what the problem might be... kindly share with me.



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