IGMP on 6500 versus 4500

[oquintasfontal]

Hi all,

I encountered a problem migrating configuration from Cisco 4500 with IOS 12.2(53)SG4 to Cisco 6500-VSS with IOS 12.2(33)SXI7.

With 4500, we had  2 servers with JBoss running multicast to build up the cluster. They used 239.X.X.X multicast IP.

There was no need to configure "ip igmp snooping vlan XX static XXXX.XXXX.XXXX interface X" neither static arp entry.

When we migrated to 6500 in VSS, we had to do:

mac-address-table static XXXX.XXXX.XXXX vlan XX interface X disable-snooping

With this command, the JBoss cluster worked well.

The question is, ¿Is there any difference regarding IGMP in 4500 versus 6500?

Kind Regards.

[Edison Ortiz]

What version of code was running the 4500? IGMP Snooping Querier was introduced with 12.2(50)SG and if you were running an older version, IGMP Snooping may have not working properly unless you had a IGMP Querier configured in another device.

The 6500, has IGMP Querier enabled and a IGMP Snooping Table is created for tracking multicast groups.

Based on your description, the 4500 was simply flooding the multicast traffic to all ports from such Vlan.

[oquintasfontal]

Hi Edison,

I was using IOS 12.2(53)SG4 on 4500, so it had IGMP Querier. In that case, the Jboss cluster (based on multicast) worked well with the default configuration in the 4500 switch

When we migrated to 6500, we had to explicity disable igmp-snooping for that multicast MAC. Is there any specific reason for this?

Thank you very much Edison.

Kind Regards.

[Edison Ortiz]

It is a similar behavior as Microsoft NLB

http://www.cisco.com/en/US/products/hw/switches/ps708/products_configuration_example09186a0080a07203.shtml

Please read the multicast mode section for explanation on why you need to disable snooping.

Essentially, the disable snooping option is only mandatory for the 6500, other platforms, this option is not required.

Regards,

Edison