multicast traffic being forwarded to 6500 MSFC CPU

[deepak.kulshreshtha]

We have two switches on which we have enabled snooping, these two switches connect to two 6500 Hybrid routers (routers don't have multicast routing or IDMG enabled on them) . Is it normal for me to see the multicast traffic reach the router CPU, shouldn't the router ports be pruned by IGMP snooping at the switch level?

[mchin345]

As far as I know the Catalyst 6000 switches can distinguish IGMP control traffic from multicast data traffic. When IGMP is enabled on the switch, IGMP control traffic is redirected to the CPU for further processing. This process is performed in hardware by specialized ASICs, which allow the switch to snoop IGMP control traffic with no performance penalty.

For more details :

http://www.cisco.com/en/US/products/hw/switches/ps708/products_configuration_guide_chapter09186a008007fb29.html

http://www.cisco.com/en/US/products/hw/switches/ps708/products_configuration_guide_chapter09186a0080179590.html