Multicast traffic L2 in Switch Nexus

[joao.beca]

Someone has any ideia?

I have 2 N5K peers and 1 N7K peer in my Datacenter. The N7K is Switch Core and both N5K peers connected to it by VPC that I´ll call them (AB-01/AB-02) and (DE-01/DE-02).

I have 4 servers in the N5K peer DE-01/DE-02 that works fine with each other by Multicast in the same VLAN and I installed one machine in the N5K peer AB-01/AB-02 that I receive the Multicast Packet from the others servers, and I see in the interface by TCPDUMP this server sending Multicast packet but I don´t receive that packets in peer DE-01/DE-02 in any server.

I disabled the IGMP snooping in the VLAN associated that I want them to communicate in all my network, the N5K peers and N7K Switch Core to the packets flow by broadcast.

[anazarenko]

You need to introduce igmp querier for igmp snooping to work correctly. 

[joao.beca]

Hi Ana,

In the Cisco document, they says that if you disabled the IGMP, it would work as broadcast traffic in the solution 5.

http://www.cisco.com/c/en/us/support/docs/switches/catalyst-6500-series-switches/68131-cat-multicast-prob.html

[David Silva]

Hello,

You need to verify that the server in AB-01/AB-02 is a part of the multicast group to be abel to receive the traffic. You do NOT need to be a memeber of a group to send traffic to said group.

On AB-01/AB-02, look at the output of "show ip igmp snooping groups vlan X" and find the muliticast address that is being used. Make sure that you see your server interface as a member of that group. If you don't see it there, that means it isn't sending any multicast joins for that group address. That would be the first thing I would check out.

Let me know what you find out.

-David

[joao.beca]

Hello David, Thanks for the advice.

I had done it before but here is the output. It don´t show nothing:

AB-01# sh ip igmp snooping groups vlan 2535
Type: S - Static, D - Dynamic, R - Router port

Vlan  Group Address      Ver  Type  Port list
AB-01#

AB-02# sh ip igmp snooping groups vlan 2535
Type: S - Static, D - Dynamic, R - Router port

Vlan  Group Address      Ver  Type  Port list
AB-02#

Maybe, It could be because we disabled the igmp snooping?

Hugs

[joao.beca]

Hello for everyone.

The problem was the new server had been configured with the MTU 9000 in the interface, and the other servers were configured with MTU 1500.

Hugs.