3Com 10014299 manual Displaying and Debugging Igmp, Igmp Configuration

508CHAPTER 34: CONFIGURING IGMP

Restore the default value of IGMP maximum query response time

undo igmp max-response-time

The default maximum query response time is 10 seconds but ranges from 1 to 25 seconds.

This configuration can only be carried out if the current router interface is operating IGMP Version 2.

Configuring Subnet When there are several routers operating IGMP in a subnet, one router is chosen Querier Survival Time to serve as a querier to take charge of sending query messages to other routers in the network segment. In the network initialization, all the routers in the network

segment act as querier by default, and send general query messages to all the multicast hosts in the subnet the routers connect to. Meanwhile, they compare the receiving IP address of the query message interface with the sending IP address of the query message interface. The router with the minimum IP address in the subnet will be chosen as querier, and the other routers become non-queriers.

All the non-queriers start the other querier present interval timer. Before the timer times out, if the query message from the querier is received, the timer resets. If the timer times out, all the routers reset as querier. The querier selection process restarts.

Make the following configuration in the interface view.

Table 581 Configure Subnet Querier Survival Time

Operation	Command
Configure subnet Querier survival time	igmp timer querier-present seconds
Restore the default value of the subnet	undo igmp timer querier-present
Querier survival time

By default, subnet querier timeout is 250 seconds.

This configuration can only be carried out if the current router interface is operating IGMP Version 2.

Displaying and Debugging IGMP

Table 582 Display and Debug IGMP

Operation	Command
Display the group membership status in	display igmp group [ group-address
the direct connecting subnet	interface type number ]
Display IGMP interface configuration	display igmp interface [ type number
information	]
Turn on the switch of IGMP debugging	debugging igmp { all event host
information	packet timer }

	After the previous configuration, execute the display command in all views to
	display IGMP configuration, and to verify the effect of the configuration. Execute
	the debugging command in system view to debug IGMP.
IGMP Configuration	Router A, Router B and a PC connect to one another through a Hub, and their
Example	interfaces are all fast Ethernet (FE).