I am connecting TRIAX STB A235-N1x-hd setup box with X440 switch and also the receiver to do L2 multicasting but it freezes after 4-5 minutes and resumes once I restart the setup box. I tried disconnecting/connecting the cable from switch and restarting the switch but it does'nt work. I have to restart the setup box to resume the freeze. I also tried changing the timers of igmp and igmp snooping but in vain. Please help
As far as figuring out if this a switch/network problem have you confirmed the streams are good before they get to the 440? We use testing gear by IneoQuest for IPTV delivery assurance and test stream direct off feeds and then deploy smaller devices at edge to verify network is sound. From my experience pixelation is not network it is content and encoding issues where there is to much compression and you end up with moments of grainy pixelated playback. Dropped frames due to network show up as skips and freezes like you were dealing with in the beginning ... Good hunting with your efforts.
Are we talking MPEG2 or MPEG4? Packet loss will give different visual artifacts, being worse with MPEG4. Usually with MPEG4, you go back to the base frame (is that an I frame? not sure anymore of the correct terminology :)), so visualy you have a lot of pixelisation, then an old frame and your back to the stream at the next I-frame.
Are the fast moving images of sport channel producing a higher bitrate stream? (are you re-encoding the streams?).
Check your buffer usage, and eventually try to adapt it on the required port if needed.