EXEC Privilege modeshow ip igmp groupsExample of the show ip igmp groups CommandDell# show ip igmp groupsTotal Number of Groups: 2IGMP Connected Group MembershipGroup Address Interface Mode Uptime Expires Last Reporter225.1.1.1 TenGigabitEthernet 1/1 IGMPV2 00:11:19 00:01:50 165.87.34.100225.1.2.1 TenGigabitEthernet 1/1 IGMPV2 00:10:19 00:01:50 165.87.31.100Adjusting TimersThe following sections describe viewing and adjusting timers.To view the current value of all IGMP timers, use the following command.• View the current value of all IGMP timers.EXEC Privilege modeshow ip igmp interfaceFor more information, refer to the example shown in Viewing IGMP Enabled Interfaces.Adjusting Query and Response TimersThe querier periodically sends a general query to discover which multicast groups are active. A group must have at least one host to beactive.When a host receives a query, it does not respond immediately, but rather starts a delay timer. The delay time is set to a random valuebetween 0 and the maximum response time. The host sends a response when the timer expires; in version 2, if another host respondsbefore the timer expires, the timer is nullified, and no response is sent.The maximum response time is the amount of time that the querier waits for a response to a query before taking further action. The querieradvertises this value in the query (refer to the illustration in IGMP Version 2). Lowering this value decreases leave latency but increasesresponse burstiness because all host membership reports must be sent before the maximum response time expires. Inversely, increasingthis value decreases burstiness at the expense of leave latency.When the querier receives a leave message from a host, it sends a group-specific query to the subnet. If no response is received, it sendsanother. The amount of time that the querier waits to receive a response to the initial query before sending a second one is the lastmember query interval (LMQI). The switch waits one LMQI after the second query before removing the group from the state table.• Adjust the period between queries.INTERFACE modeip igmp query-interval• Adjust the maximum response time.INTERFACE modeip igmp query-max-resp-time• Adjust the last member query interval.INTERFACE modeip igmp last-member-query-interval376 Internet Group Management Protocol (IGMP)
