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Community Member

SG300 Multicast routing and setup


I have some issues setting up 2 SG300 and IPTV MC-sources to work as expected.
I have 3 sources connected to an SG300-10 which also serves some clients in our network. The SG300-10 is connected to a SG300-28 which can be seen as our "main or central" switch where our servers and most of the clients are connected to.
I have

- enabled Bridge Multicast Filtering with Forwarding method IP group address, on both switches

- enabled IGMP snooping with default values + immediate leave, on both switches

- enabled IGMP querier on both switches and they elected the one with the lower IP as operational (as supposed)

- filtering unregistered MC on every port, on both switches

Basically, this works, for some of the streams. I found that it works for the streams that are somehow automagically detected and are listed in the IP Multicast Group Address listing in the SG300-10 which is connected to the sources.
Why are not all the streams detected and listed? Why do I have to add some manually?
(I did not have to setup these manually on the SG300-28. The automatic ones are always there and the other ones are added dynamically when viewed)

The listing in IGMP/MLD IP Multicast Group - as I understand it - should list all streams currently forwarded and which ports are included. On the SG300-10 I always only see the streams that have been detected automatically and only with its source port included, even if the stream is currently viewed on some ports of the SG300-28. Is this normal behavior? How do I see all streams that are currently forwarded?
(On the SG300-28 this behaves as expected. I can see exactly which port is included in which stream)

Another thing I don't understand: Why is the the link between the 2 SG300' flooded with all the data from every stream even if nobody on the SG300-28 is requesting or viewing any of the streams? This is flooding this link with unwanted and unneeded traffic. If nobody is requesting a stream on the SG300-28 it must be removed from the link.

The link port between the SG300-10 and the SG300-28 is listed as dynamic MRouter port from the SG300-10 point of view. The SG300-28 does not list any port as MRouter.

There seems to be a configuration issue. I had 2 low cost Netgear switches in place of these SG300' before and none of the above happened. With the Netgear I simply activated IGMP snooping with Querier and all worked out of the box.
I somehow don't believe that this is not possible with these SMB switches.

Thanks for any suggestions or a link to a guide on how to set up these switches for MC operation.

Everyone's tags (1)
Community Member

Really? Nobody has any input

Really? Nobody has any input for me on that? sad

Community Member

Bump ... or how do I file a

Bump ... or how do I file a support request?

Whatever I do, it simply does not work as (IMHO) supposed!

Community Member

Bump again !Nobody here that

Bump again !

Nobody here that has a good hint ... except replacing the Cisco stuff with some others wink

Community Member

Please search for 'SG300-52

Please search for 'SG300-52 acts like a hub' and see if the issue may apply to you. I seem to have the same 'acts like a hub' issue where with multicast disabled and indeed a very plain setup all traffic appears flooded to all ports saturating them at heavy traffic times.


Community Member

Andrew,Thanks for trying to


Thanks for trying to help. It does not seem to be a similar issue.
I had a remote with support and will have another one today ... since they could not tell me what's wrong after 3 hours remote on Friday surprise.

I hope today will bring a solution - other than taking out the Cisco SMB switches and putting back in some other brand like Netgear wink.



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