Cisco Systems 3750E manual Changing the Maximum Query Response Time for IGMPv2, 42-33

Chapter 42 Configuring IP Multicast Routing

Configuring Optional IGMP Features

	Command	Purpose
Step 5
	show ip igmp interface [interface-id]	Verify your entries.
Step 6
	copy running-config startup-config	(Optional) Save your entries in the configuration file.

To return to the default setting, use the no ip igmp querier-timeoutinterface configuration command.

Changing the Maximum Query Response Time for IGMPv2

If you are using IGMPv2, you can change the maximum query response time advertised in IGMP queries. The maximum query response time enables the switch to quickly detect that there are no more directly connected group members on a LAN. Decreasing the value enables the switch to prune groups faster.

Beginning in privileged EXEC mode, follow these steps to change the maximum query response time. This procedure is optional.

	Command	Purpose
Step 1
	configure terminal	Enter global configuration mode.
Step 2
	interface interface-id	Specify the interface to be configured, and enter interface configuration
		mode.
Step 3
	ip igmp query-max-response-time	Change the maximum query response time advertised in IGMP queries.
	seconds	The default is 10 seconds. The range is 1 to 25.
Step 4
	end	Return to privileged EXEC mode.
Step 5
	show ip igmp interface [interface-id]	Verify your entries.
Step 6
	copy running-config startup-config	(Optional) Save your entries in the configuration file.

To return to the default setting, use the no ip igmp query-max-response-timeinterface configuration command.

Configuring the Switch as a Statically Connected Member

Sometimes there is either no group member on a network segment or a host cannot report its group membership by using IGMP. However, you might want multicast traffic to go to that network segment. These are ways to pull multicast traffic down to a network segment:

•Use the ip igmp join-groupinterface configuration command. With this method, the switch accepts the multicast packets in addition to forwarding them. Accepting the multicast packets prevents the switch from fast switching.

•Use the ip igmp static-groupinterface configuration command. With this method, the switch does not accept the packets itself, but only forwards them. This method enables fast switching. The outgoing interface appears in the IGMP cache, but the switch itself is not a member, as evidenced by lack of an L (local) flag in the multicast route entry.

	Catalyst 3750-E and 3560-E Switch Software Configuration Guide
OL-9775-02		42-33