To Next Page

To Previous Page

To modify this interval:

1. Configure the time (in seconds) that the routing device waits for a report in response

to a group-specific query.

[edit protocols igmp]

user@host# set query-last-member-interval 0.1

2. Verify the configuration by checking the IGMP Last Member Query Interval field in the

output of the show igmp interfaces command.

NOTE: You can configure the last-member query count by configuring the

robustness variable. The two are always equal.

Documentation

Modifying the IGMP Robustness Variable on page 456•

• show pim interfaces

Modifying the IGMP Robustness Variable

Fine-tune the IGMP robustness variable to allow for expected packet loss on a subnet.

The robust count automatically changes certain IGMP message intervals for IGMPv2 and

IGMPv3. Increasing the robust count allows for more packet loss but increases the leave

latency of the subnetwork.

When the query router receives an IGMP leave message on a shared network running

IGMPv2, the query router must send an IGMP group query message a specified number

of times. The number of IGMP group query messages sent is determined by the robust

count.

The value of the robustness variable is also used in calculating the following IGMP

message intervals:

•

Group member interval—Amount of time that must pass before a multicast router

determines that there are no more members of a group on a network. This interval is

calculated as follows: (robustness variable x query-interval) + (1 x

query-response-interval).

•

Other querier present interval—The robust count is used to calculate the amount of

time that must pass before a multicast router determines that there is no longer another

multicast router that is the querier. This interval is calculated as follows: (robustness

variable x query-interval) + (0.5 x query-response-interval).

•

Last-member query count—Number of group-specific queries sent before the router

assumes there are no local members of a group. The number of queries is equal to the

value of the robustness variable.

In IGMPv3, a change of interface state causes the system to immediately transmit a

state-change report from that interface. In case the state-change report is missed by

ACX Series Universal Access Router Configuration Guide

Juniper ACX2000 Configuration Guide

Other manuals for Juniper ACX2000