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Router/Switch performance issue with IP Multicast Routing

I have a Cisco 6509 core switch that supports 13 VLANS and is running OSPF for IP and RIP for IPX. We have video/audio streaming server. When we enabled IP multicast routing on the switch the multimedia content streamed fine on three of the VLANS we enabled, but other IP-based applications started running slow. We suspect that there is a processor load isssue. I also believe that IGMP snooping may still be enabled which may be causing the problem, but hopefully someone can confirm this.

Here is the config we put on the core switch and closet switches to the desktop respectively. Can someone please tell me if something is missing.


On the core switch:

Router (config)# ip multicast-routing

Router (config)#interface vlan <vlan-id>

Router (config-if)#ip pim dense-mode

Router (config-if)# ip multicast ttl-threshold 15

Router (config-if)# ip igmp join-group <multicast address>

Router (config-if)# ip igmp version 2

Router (config-if)# ip cgmp

On the edge switches:

Switch (enable) set cgmp enable

Switch (enable) set cgmp leave enable


Re: Router/Switch performance issue with IP Multicast Routing

You can use the 'show processes' to check the CPU utilization. You can also use the 'show ip igmp snooping mrouter' to verify whether snooping is enabled or disabled on the vlans. If the address that you are using in the 'ip igmp join-group' command is the one to which the multicast stream is sent, this could load the router. I am not sure for what reason you are using this command, but this command might not be needed since the router will discover attached receivers automatically through IGMP.


Re: Router/Switch performance issue with IP Multicast Routing

Multicast flows may be processed by the MSFC instead of the PFC if the "ip igmp join-group " is used, this would have an affect on your performace.