why is it not possible to use multicast ssm with vpc in nexus 7000?

[9w.boye]

Hi,

at the moment I am testing a typical nexus 7000 setup (2 Data Centers with each 2 N7K).

Between the Data Centers we have a mpls core to support inter-vlan-routing inside of different vrfs.

For multicast transport inside a vrf we use multicast vpn (mdt).

It works fine.

What I am now wondering is: With VPc on the vlan-site towards the end devices, the documentation states that multicast source specific multicast (ssm) is not possible for a VPC setup.

http://www.cisco.com/en/US/docs/switches/datacenter/sw/6_x/nx-os/interfaces/configuration/guide/if_vPC.html#wp1804175

As part of a proven and recommended design we have a pair of N5K attached towards the pair of N7K with a "double-sided vpc".

Multicast transport works fine when I have an asm-group stream with a rendez-vous point in place.

The same stream with the same sender and receiving devices as a ssm-stream with "ip igmp version 3" on the vlan side and a defined ssm-range inside the vrf-definition also works, but I receive every packet twice at the receiver-side.

So  I can confirm that ssm is not working correctly with vpc. But I would like to understand why - and of course I would like to know if some updates of this restriction can be expected.

regards, William

[Reza Sharifi]

Hi,

This limitation still exist in 6.1 and 6.2.  If you want to know if it will be added in future software releases, talk to your SC, so they can bring it up to the attention of the 7000 series BU (Business Unit).  They BU can tell you if and when they will add this to the later versions of the Nexus OS.

HTH