[mythtv-users] IGMP snooping

[Mark Perkins]

I am experimenting with a multicast stream into mythtv using the IPTV recorder functionality. Originally I only had dumb switches so when in multicast mode the stream was sprayed all over the network, but it worked fine (well, other than the network load - but the network seemed to handle it without complaint mostly because my WiFi router has an option to prevent multicast traffic getting sprayed over wireless). However I don't want the unnecessary load on the network (and potential future problems) so I have upgraded to smart switches so that I can use IGMP snooping so that only the port that is subscribed / listening to the multicast stream receives the stream.

However this is where I have hit an issue. I have worked out that when I open the stream in mythtv the BE causes the port to subscribe to the stream and I can see this reflected in the multicast table via the smart switch webpage and everything works perfectly as per before. But after about 4 - 5min "something" happens and the port stops listening to the stream and drops off the multicast table. The backend starves of packets and the recording fails at that point.

I am guessing that the "something" is the IGMP snooping timing out - but I am hoping someone with knowledge on how it works can confirm.

Is mythBE supposed to renew the IGMP snooping request every x minutes? Is there any logging I can enable on mythBE to see whether this is occurring or see what the interval is?

Or do I have this backwards, is the switch supposed to keep the port subscribed to the multicast stream until mythBE unsubscribes itself?

Running fixes/0.28 updated about 2 months ago.