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

Set the maximum query response time advertised in

seconds>

IGMP queries.

 

 

Configuring the Router as a Statically Connected Member

To configure the router itself to be a statically connected member of a 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.

 

 

Configuring the TTL Threshold

The time-to-live (TTL) value controls whether packets are forwarded out of an interface. The TTL value is specified in hops. Only multicast packets with a TTL value greater than the interface TTL threshold are forwarded on the interface. The default value is 0, which means that all multicast packets are forwarded on the interface.

To change the default TTL threshold value, use the following command in interface configuration mode:

Command

Purpose

 

 

ip multicast ttl-threshold <0-255>

Configure the TTL threshold of packets being forwarded

 

out an interface.

 

 

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Asante Technologies 35516 user manual Command, Changing the Igmp Version, Seconds, Igmp queries