ip igmp query-interval [seconds] By default this timer is set to 60 seconds. It is a periodic interval defining how often the querier sends IGMP host-query messages from an interface. The default is 60 and it is configurable between 1 and 18000.
ip igmp query-max-response-time [seconds] Defines the maximum response time in which a host must respond to an IGMP query. When a host receives the query packet, it starts counting to a random value, less that the maximum response time. When this timer expires, host replies with a report, provided that no other host has responded yet. This accomplishes two purposes:
- allows controlling the amount of IGMP reports sent during a time window
- engages the report supression feature, which permits a host to suppress its own report and conserve bandwidth With IGMPv1, there is no max-response-time tuning and it is fixed at 10 seconds.
ip igmp last-member-query-interval [ms] IGMP uses this value when a router hears an IGMPv2 Leave report. After a router receives the Leave report, it checks that the interface is not configured for IGMP Immediate Leave (single-host on the segment) and if not, it sends out an out-of-sequence query. The maximum-response-time in this query is set to last-member-query-interval which is 1000ms by default.
ip igmp last-member-query-count[number] Continuing from above, a router will send a maximum of last-member-query-count messages after receiving a Leave report from a host. If no one responds during this time, the router removes the IGMP state for the group.
ip igmp immediate-leave group-list [list] Multicast groups defined by the list will be treated as having a single host member. After the reception of a Leave message, the router immediately removes the multicast forwarding state.
ip igmp query-timeout [seconds] This timer is used by “silent” routers, ie the routers that lost the Querier election. If the inactive routers do not hear any queries for 2 times the query-timeout, they start the election process again. The default is 120 seconds.