Changing the IGMP Snooping Group Timeout Value on Switches

The IGMP snooping group timeout value determines how long a switch waits to receive an IGMP query from a multicast router before removing a multicast group from its multicast cache table. A switch calculates the timeout value by using the query-interval and query-response-interval values.

When you enable IGMP snooping, the query-interval and query-response-interval values are applied to all VLANs on the switch. The values are:

• query-interval—125 seconds

• query-response-interval—10 seconds

The switch automatically calculates the group timeout value for an IGMP snooping-enabled switch by multiplying the query-interval value by 2 (the default robust-count value) and then adding the query-response-interval value. By default, the switch waits 260 seconds to receive an IGMP query before removing a multicast group from its multicast cache table: (125 x 2) + 10 = 260.

You can modify the group timeout value by changing the robust-count value. For example, if you want the system to wait 510 seconds before timing groups out—(125 x 4) + 10 = 510—enter this command: