Multicast on ASR920 not working as expected

[wipo]

Hi,

We are testing an ASR920 in our lab and noticed that multicast is not working as expected.

When we create a network with 3 switches (c2960) with mostly default settings evertything works fine.

unicast form host A-B: ok

broadcast from host A-B: ok

multicast from host A-B: ok 

But when we replace switch 3 by an ASR920 multicast does not work anymore. Although the ports are in the same BD and igmp snooping is enabled.

unicast form host A-B: ok

broadcast from host A-B: ok

multicast from host A-B: not working

Can somebody explain the difference between the two setups and why multicast is not working with the ASR920.

[mlund]

Hi

I got the exact same behavior. But it works by entering "ip pim sparse-mode" under "interface bdi 10"

My understanding is that the asr needs a querier to connect the different evc. And the ip pim sparse-mode enables the querier function. It will probably work if you configure the querier function in switch 1 or 2 instead. I did not tried it.

I wonder if anyone knows about another way to get this to work.

/Mikael

[ronit]

I have a similar problem and was wondering if Mikael's suggestion worked? I started another thread here

ASR920s not passing Layer 2 Multicast Traffic within the same BD - Cisco Community

[wipo]

The solution works in this specific networktopology. But when using the ASR920 as router&switch and adding secondary (redundant) routers to this network the solution did not work and caused other problems.

[ronit]

Thanks. For my issue, I ended up disabling igmp snooping for this specific BD and it worked.