facing a problem of double multicast on one of our cisco 3750 switch. On checking with sniffer it was found that out of double packet’s one packet is having source mac-address of vlan and another packet is having a source mac-address of switch base mac-address. Please analyze the issue and let us know what is the problem.
attached here show tech-support of reported switch,
Remove all 'ip igmp join-group' from all interface vlans. This isn't needed and it causes the router to process all multicast packets in software. You can potentially Denial Of Service the switch with this configuration.
Thanks, but we will not be able to remove the igmp join-group as the switch host multicast traffic. Please let me know if there is any other work arround...
you can use [ ip igmp static-group x.x.x.x] in its place, this is similar to igmp join-group except it wont process the traffic in cpu.