Viewing IGMP GroupsTo view both learned and statically configured IGMP groups, use the following command.• View both learned and statically configured IGMP groups.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 LastReporter225.1.1.1 TenGigabitEthernet 1/1/1 IGMPV2 00:11:19 00:01:50165.87.34.100225.1.2.1 TenGigabitEthernet 1/1/1 IGMPV2 00:10:19 00:01:50165.87.31.100Adjusting 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 groupmust have at least one host to be active.When a host receives a query, it does not respond immediately, but rather starts a delay timer. The delaytime is set to a random value between 0 and the maximum response time. The host sends a responsewhen the timer expires; in version 2, if another host responds before the timer expires, the timer isnullified, and no response is sent.The maximum response time is the amount of time that the querier waits for a response to a querybefore taking further action. The querier advertises this value in the query (refer to the illustration in IGMPVersion 2). Lowering this value decreases leave latency but increases response burstiness because all hostmembership reports must be sent before the maximum response time expires. Inversely, increasing thisvalue 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. Ifno response is received, it sends another. The amount of time that the querier waits to receive a responseto the initial query before sending a second one is the last member query interval (LMQI). The switchwaits one LMQI after the second query before removing the group from the state table.• Adjust the period between queries.Internet Group Management Protocol (IGMP) 361
