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Question

Need help with a configuration involving 3 summit x-440-24 and 3 cidco sg300-10mp


Hi everyone!
I am trying to implement an AV network involving several deivces all using multicast streams. My main network is composed of 3 Summit x-440-24t and 3 "secondary" cisco SG300-10MP.
I can ping all devices from everywhere in the network but my multicast streams don't reach their destinations.
there is no fancy configuration on any of the switches. Just multicast and IGMP Snooping.
Everything is on the same VLAN.
I am sure that I am dealing with a protocol incompatibility at some point but I am not a hardcore IT person, so I don't really know where to look.
Spanning tree protocol?
Querier status?
IGMP Snooping difference on respective brands?

Any help is welcome!

4 replies

Userlevel 5
For starters you'll need to confirm that you have IGMP snooping enabled on the VLAN on each participating switch. The command below will show what VLANs currently have IGMP snooping enable. IGMP is a standard protocol, so regardless of the vendor, if you have the same version, it should work just fine
show igmp snooping[/code]Next check to verify the version of IGMP running on each device participating in the multicast stream. IGMPv3 is backward compatible with IGMPv2, but IGMPv2 is not forward compatible with IGMPv3. So if you have a device dishing out v3 INCL, but the device receiving those includes only understands v2 JOINs, it most likely wont work. To verify the version run the following command:
show igmp snooping [/code]Next, you need to verify that the Sender is actually sending the multicast stream and it is arriving on the switch, you can run the following commands to verify this:
show mcast cache
show igmp group[/code]the show igmp group command shows both senders that are currently active on a VLAN and receivers, if any are currently subscribed.

If your unicast streams are working, I don't see how STP could affect the mcast stream, as far as I know, it cannot tell the difference.

If you're still having trouble with the stream, mirror the port that one of the senders is connected on and run a wireshark capture to see what it is sending. Here's an article on how to configure a mirror in a EXOS: https://gtacknowledge.extremenetworks.com/articles/How_To/How-To-Enable-And-Configure-Mirroring-In-E...

I hope this helps. If you have any more questions, please feel free to ask!
Userlevel 6
Are you routing the multicast streams or just L2 switching. If you route the multicast streams you need to configure pim.
Hi,
Thanks for the answers
Unfortunately, i am still having the same problems
multicast streams drops randomly and every time a source is reassigned

I tried investigating the igmp snooping as suggested and everything looks normal. (I had big hopes on this one 🙂 )

I just need L2 switching but I am not sure how the switch is configured out of the box (anything L3 specific?)
Userlevel 6
Our switch uses igmp snooping which relies on igmp messages. For this an IGMP querier needs to exist on the vlan for igmp snooping to work correctly. The IGMP querier will send queries on which the subscribers respond which gives the switch the opportunity to update its snooping table. A dirty workaround could be disabling igmp snooping but that will result on flooding of all streams to all ports in the vlan.
Another option could be static igmp group entries (conf igmp snooping port add static group on all the ports you want the stream to be delivered.
if the problem is the IGMP querier you could give the switch an ip address on the vlan.

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