Issue Description
Topology:
Broadcast Server--------S9306-------- Broadcast Client
Client required that S9300 realize broadcast by pure layer 2 broadcast technic, it found that client interface can receive broadcast stream normally after configuring igmp snooping on S9306, but it can last for about 3 minutes. View the layer 2 broadcast forwarding table on S9306, it found that when client did broadcast on-demand operation, S9306 broadcast table can established normally, but last for 3 minutes, broadcast forwarding interrupt after broadcast forwarding table disappear.
Handling Process
1. After test and layer 2 broadcast forwarding table view, confirm that this problem will appear surely.
2. Change igmg snooping to igmp proxy, find that broadcast forwarding is normal. S9306 who enabled igmp proxy can query whether client is used by sending igmp packet before layer 2 broadcast forwarding table old, S9306 will refurbish layer 2 broadcast forwarding table if client is using it, make sure broadcast forwarding is lasting.
3. Change igmp proxy to igmp snooping, configure igmp-snooping querier enable command, this command force S9306 to send igmp query packets for refurbishing layer 2 broadcast forwarding table aging time when S9306 run igmp snooping, make sure broadcast forwarding is lasting.
Root Cause
Client send igmp report packets when client begin to click on-demand, so layer 2 broadcast forwarding table can establish normally, but after table old, igmp snooping does not trigger update mechanism, so unless client click on-demand again, layer 2 broadcast forwarding table will be empty.
