User`s manual

Enable the IGMP querier
Multicast switches can send IGMP host-query messages to discover which multicast groups are present on attached
networks. These messages are sent to the all-systems group address of 224.0.0.1 with a time-to-live (TTL) value
of 1.
Multicast switches continue to periodically send host-query messages to refresh their knowledge of memberships
present on their networks. If, after some number of queries, the switch software discovers that no local hosts are
members of a multicast group, the software stops forwarding onto the local network multicast packets from remote
origins for that group and sends a prune message upstream toward the source.
The switch can be configured to send IGMP queries which are used to solicit IGMP hosts report messages. The
switch uses the report messages to keep track of which ports belong to which IP multicast group.
To enable/disable IGMP querier , use the command below:
Command Purpose
set igmp-querier {enable | disable}
Enable/Disable IGMP querier
Modifying the IGMP Host-Query Message Interval
Multicast switches elect a designated switch for the LAN (subnet). The designated switch is the one with the highest
IP address. The switch is responsible for sending IGMP host-query messages to all hosts on the LAN. By default, the
designated switch sends IGMP host-query messages every 60 seconds in order to keep the IGMP overhead on hosts
and networks very low. To modify this interval, use the following command in interface configuration mode:
Command Purpose
set igmp query-interval <10-3600 seconds>
Configure the frequency at which the designated switch sends
IGMP host-query messages.
The following example shows setting the IGMP query interval to 200.
Switch(config)# set igmp query-interval 200
Changing the Maximum Query Response Time
By default, the maximum query response time advertised in IGMP queries is 10 seconds. If the switch is using IGMP
Version 2, you can change this value. To change the maximum query response time, use the following command in
configuration mode:
Command Purpose
set igmp query-resinterval <0-200 seconds>
Set the maximum query response time advertised
in IGMP queries.
49 Asante IntraCore IC39240/480 User’s Manual