Configuring Interfaces for IGMP

Syntax:

set igmp interface <Name of Interface>

      last-member-query-interval {<1-25> | default}

      local-group address {off | on}

      loss-robustness {<1-255> | default}

      query-interval {<1-3600> | default}

      query-response-interval {<1-25> | default}

      router-alert {off | on}

      static-group address {off | on}

      version <1 | 2 | 3>

Note - IGMP version 2 runs by default.

Important - In a cluster, run commands on each cluster member. The configuration of each cluster member must be identical

Parameters:

Parameter

Description

interface <Name of Interface>

Specifies the interface, on which IGMP should be configured.

last-member-query-interval {<1-25> | default}

The maximal response time (in seconds) inserted into IGMP group-specific queries.

You can use the last member query interval to tune the "leave latency."

A smaller value results in a reduction in the time to detect the loss of the last member of a multicast group.

This value must always be less than the query interval.

Range: 1-25

Default: 1

local-group address {off | on}

A multicast group address. A local group provides a mechanism to simulate the presence of local receivers for specific groups.

When a multicast group is added to an interface, IGMP sends a membership report on the interface.

Range: off, on

Default: off

loss-robustness {<1-255> | default}

Lets you tune the expected packet loss on a subnet.

If you expect the subnet to be highly lossy, then you can increase the "loss robustness" value.

IGMP protocol operation is robust to (lossrobustness - 1) packet loss.

Range: 1-255

Default: 2

query-interval {<1-3600> | default}

The interval (in seconds) between IGMP general queries which the querier router sends.

You can use this parameter to tune the IGMP messaging overhead and has a secondary effect on the timeout of idle IP multicast groups.

Range: 1-3600

Default: 125

query-response-interval {<1-25> | default}

The maximal response time (in seconds) inserted into the periodic IGMP general queries.

You can use the query response interval to tune the burstiness of IGMP messages.

A larger value spreads the host IGMP reports over a larger interval, which reduces burstiness.

This value must always be less than the value of the "query-interval".

Range: 1-25

Default: 10.

router-alert {off | on}

Lets you disable the insertion of IP router alert in all IGMP messages sent on the interface.

This can be useful with broken IP implementations that may discard the packet because of the use of this option.

Range: off, on

Default: off

static-group address {off | on}

A multicast group address. A static group provides a mechanism to simulate the presence of local receivers on an interface.

When a static group is configured on an interface that also runs a parent multicast protocol (such as PIM), IGMP informs the parent of the presence of a local receiver.

In contrast to regular IGMP, no membership reports are sent on the corresponding interface.

If the same multicast group is configured as both a local and a static group, local group takes precedence, that is, membership reports are sent out on the interface.

Range: off, on

Default: off

version <1 | 2 | 3>

IGMP version 2 is compatible with IGMP version 1.

IGMP version 3 is compatible with IGMP versions 2 and 1.

Best Practice - Use IGMP version 1 only on networks that include multicast routers that are not upgraded to IGMP versions 2 or 3.