IGMP snooping


I have a query on IGMP snooping and Multicasting.

I have video on demand and video streaming on an old infrastructure and I'm swapping out the old for the new.. I want IGMP snooping on to stop the video multicast traffic from flooding the network but I dont want to stop other multicasts from flooding.. In my lab if I enable the IGMP it works a treat but this also blocks all other unknown multicast traffic..

How do I enable IGMP snooping for known groups without blocking other unknown multicast traffic from flooding?

Ta very muchly.

Reply to
Loading thread data ...

What are these other multicasts? Don't the listeners to those other multicast groups also use IGMP to join/leave the groups? If so, IGMP snooping would be able to catch those and do the right thing to avoid flooding. Why do you want those groups to flood?

Or is it that those multicast groups are source-only multicasts? That is there are no explicit listeners but multicast servers are multicasting data out on those groups. IGMP snooping will detect those streams and should add a multicast entry for that group with only the router port.

Cisco da Gama

formatting link

Reply to

It is because they are internally developed multicast clustering system that does not use the IGMP Join/leave facility. They just expect that certain participating machines will hear them. It is the bit you quote that is interesting -

"IGMP snooping will detect those streams and should add a multicast entry for that group with only the router port."

There is no router port involved.. this is purely layer two running on a single 6500.. what I see happening is as soon my server pushes a multicast out to say I see the first packet flooded to all ports in its vlan and then nothing.. silence.

It seems as if the first packet is processed by the CPU and flooded.. but all consecutive packets are then dropped.

Could it be I need a static entry in my IGMP membership table as a (S,*) type entry?

Reply to

Cabling-Design.com Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.