Allied Telesis AR400 - Manual (Page 76)

Page 76 | AlliedWare™ OS How To Note: IGMP
Configurable IGMP timers and counters > Default Query Interval
Default Query Interval
What this timer does
To maintain an accurate picture of group membership, the Querier periodically sends
General Queries to all its IGMP interfaces. The Default Query Interval is the gap between
General Queries.
Note that General Queries are quite different from Specific Queries, which the Querier
sends to a group address when it receives a Leave message for that group.
The router or switch only sends General or Specific Queries if it is the Querier. If another
router or switch is elected as the Querier, the non-elected router or switch ignores the
Default Query Interval and other such settings.
Potential problems with changing this timer
If you change the Default Query Interval, the Default Timeout Interval also needs to change
so that clients have an appropriate amount of time to reply to the Query. Since software
versions 281-03 and 2.9.1, this happens automatically. For earlier versions, you need to
change it yourself as described on
page 82 .
How to change this timer
The Default Query Interval is an integer from 1 to 65535 seconds, specified using the
queryinterval parameter. The default is 125 seconds. The following example tweaks the
interval. Note that the Default Timeout Interval also changes.
Manager Switch 1> set ip igmp queryinterval=120
Info (1005003): Operation successful.
Manager Switch 1> show ip igmp
IGMP Protocol
------------------------------------------------------------------------
Status ........................... Enabled
Default Query Interval ........... 120 secs
Default Timeout Interval ......... 250 secs
Last Member Query Interval ....... 10 (1/10secs)
Last Member Query Count .......... 2
Robustness Variable .............. 2
Query Response Interval .......... 100 (1/10secs)
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