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Asante Technologies 35516 User Manual

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Multicast routers elect designated router (DR) for the LAN (subnet). The DR is the router with the highest IP address.
The DR is responsible for sending IGMP host-query messages to all hosts on the LAN. By default, the DR 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

ip igmp query-interval <1-65535
seconds>

Configure the frequency at which the designated router sends
IGMP host-query messages.

Router(config-if-veth1)# ip igmp query-interval 200

Changing the IGMP Version

By default, the router uses IGMP Version 2, which allows such features as the IGMP query timeout and the maximum
query response time.

All systems on the subnet must support the same version. The router does not automatically detect Version 1
systems and switch to Version 1. Configure the router for Version 1 if your hosts do not support Version 2.

To control which version of IGMP the router uses, use the following command in interface configuration mode:

Command Purpose

ip igmp version {2 | 1}

Select the IGMP version that the router uses.

Changing the Maximum Query Response Time

By default, the maximum query response time advertised in IGMP queries is 10 seconds. If the router is using IGMP
Version 2, you can change this value. The maximum query response time allows a router to quickly detect that there
are no more directly connected group members on a LAN. Decreasing the value allows the router to prune groups
faster.

To change the maximum query response time, use the following command in interface configuration mode:

Command Purpose

ip igmp query-max-response-time
<1-25 seconds>

Set the maximum query response time advertised in IGMP
queries.

Configuring the Router as a Statically Connected Member

To configure the router itself to be a statically connected group member, use the following command in interface
configuration mode:

Command Purpose

ip igmp static-group A.B.C.D

Configure the router as a statically connected member of a
group.