Display And Debug Igmp - 3Com 7700 Configuration Manual

172 C 6: M
HAPTER ULTICAST

Display and Debug IGMP

P
ROTOCOL
Configuring the IGMP Querier Present Timer
The IGMP querier present timer defines the period of time before the router takes
over as the querier.
Perform the following configuration in VLAN interface view.
Table 17 Configure the IGMP Querier Present Timer
Operation
Change the IGMP querier present
timer
Restore the IGMP querier present
timer to the default value
By default, the value is 120 seconds. If the router has received no query message
within twice the interval specified by the igmp timer query command, it will
regard the previous querier invalid.
Configuring the Maximum Query Response Time
When a router receives a query message, the host will set a timer for each
multicast group it belongs to. The value of the timer is randomly selected between
0 and the maximum response time. When any timer becomes 0, the host will send
the membership report message of the multicast group.
Setting the maximum response time allows the host to respond to query messages
quickly. In this case, the router can master the existing status of the members of
the multicast group.
Perform the following configuration in VLAN interface view.
Table 18 Configure the Maximum Query Response Time
Operation
Configure the maximum query
response time for IGMP
Restore the maximum query
response time to the default
value
The smaller the maximum query response time value, the faster the router prunes
groups. The actual response time is a random value in the range from 1 to 25
seconds. The default value is 10 seconds.
After the above configuration, execute display command in all views to display
the running of IGMP configuration, and to verify the effect of the configuration.
Execute debugging command in user view for the debugging of IGMP.
Table 19 Display and Debug IGMP
Operation
Display the information about
members of IGMP multicast
groups
Command
igmp timer other-querier-present seconds
undo igmp timer other-querier-present
Command
igmp max-response-time seconds
undo igmp max-response-time
Command
display igmp group [ group-address | interface
interface-type interface-number ]