02-10-2020 01:23 AM - edited 02-10-2020 07:15 AM
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.
03-17-2020 03:33 AM
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
02-19-2021 10:14 PM
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
02-21-2021 10:58 PM
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.
02-21-2021 11:03 PM
Thanks. For my issue, I ended up disabling igmp snooping for this specific BD and it worked.
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