IGMP support - prevent delivery of multicast streams to ports that haven't requested them

Hi,

Just replaced most of my network’s TP-Link switches with Alta Labs ones. I saw that a firmware upgrade was released some time ago to support IGMP snooping.

However, if I run Wireshark on my PC, I can see that multicast streams are still being delivered to my PC, despite it not requesting them. I would expect the multicast streams to be held within the switch, and only released to the ports once a client on the machine issues an appropriate IGMP message.

Is there some configuration that needs to be carried out to achieve this?

Edit: I’ve just checked, and IGMP Snooping is enabled on VLAN 1 (the only VLAN in the system).

Thanks

Andy

Which IGMP group(s) are you seeing? A limited number are flooded to all ports in the source VLAN by design, like all hosts, and we flood mDNS. If you haven’t yet upgraded to switch firmware 2.1g, there were some others like 239.x.x.x which were flooded on earlier firmware which no longer are.

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Switches are all on 2.1g, The multicast group was in the 239.192.x.x range.

In the network are 4 x Alta 8 port switches, and 1 TP-Link 16 port switch.

Andy

Thanks, there is a remaining issue with at least some 239 groups. The RTK switch SDK handles 239./8 oddly IMO, differently from others. IGMP is being setup correctly for those groups, which is what testing verified, but I missed that it may still being flooded despite that. Will take a closer look at that soon, but probably next week after the holiday as I have family in from out of town.

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So if I were to use a 238.x.x.x multicast address would you expect it to work?

Edit: I’ve just tried this and am still seeing the multicasts presented to my PC.

Andy

Have you had a chance to look at this at all?

Changing the multicast address to 238.x.x.x didn’t seem to make any difference.

Thanks

Andy