Dell PowerSwitch S4820T Configuration Guide for the S4820T System 9.100.0 - Page 345

IGMP query interval is 60 seconds IGMP querier timeout is 125 seconds IGMP max query response time is 10 seconds IGMP last member query response interval is 1000 ms IGMP immediate-leave is disabled IGMP activity: 0 joins, 0 leaves, 0 channel joins, 0 channel leaves IGMP querying router is 1.1.1.1 (this system) IGMP version is 3 Viewing IGMP Groups To view both learned and statically configured IGMP groups, use the following command. • View both learned and statically configured IGMP groups. EXEC Privilege mode show ip igmp groups Example of the show ip igmp groups Command Dell# show ip igmp groups Total Number of Groups: 2 IGMP Connected Group Membership Group Address Interface 225.1.1.1 TenGigabitEthernet 1/1 225.1.2.1 TenGigabitEthernet 1/1 Mode IGMPV2 IGMPV2 Adjusting Timers Uptime 00:11:19 00:10:19 Expires 00:01:50 00:01:50 Last Reporter 165.87.34.100 165.87.31.100 The 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 mode show ip igmp interface For more information, refer to the example shown in Viewing IGMP Enabled Interfaces. Adjusting Query and Response Timers The querier periodically sends a general query to discover which multicast groups are active. A group must 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 delay time is set to a random value between 0 and the maximum response time. The host sends a response when the timer expires; in version 2, if another host responds before 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 querier advertises this value in the query (refer to the illustration in IGMP Version 2). Lowering this value decreases leave latency but increases response burstiness because all host membership reports must be sent before the maximum response time expires. Inversely, increasing this 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 sends another. The amount of time that the querier waits to receive a response to the initial query before sending a second one is the last member 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 mode ip igmp query-interval • Adjust the maximum response time. Internet Group Management Protocol (IGMP) 345