Allied Telesis AR400 - Manual (Page 72)

Page 72 | AlliedWare™ OS How To Note: IGMP
Configurable IGMP timers and counters > Default values
Default values
Output of the command show ip igmp shows the values of the configurable IGMP settings.
The following output shows the default values.
Note that units for Last Member Query Interval (LMQI) and Query Response Interval are
0.1 seconds. Therefore, the default LMQI is 1 second and the default Query Response
Interval is 10 seconds.
Last Member Query Count and Last Member
Query Interval
The Last Member Query Count (LMQC) is the number of Specific Queries the Querier
sends after receiving a Leave message—1 to 5 messages.
The Last Member Query Interval (LMQI) is the time between the Specific Queries—1 to 255
in units of 0.1 seconds.
These counters determine how quickly a group times out when the last client leaves the
group. You should read this section in conjunction with
"How clients leave groups: queries
and timers" on page 58 , which has an outline of the leave process and a detailed discussion of
the timers.
What these counters do
On the Querier and all Snoopers, IGMP keeps group membership timeout values on each
port. During general multicasting, these timeouts are (by default) 260 seconds. When a client
leaves a group, these timeouts are reduced to make multicasting stop quickly after the last
client leaves. The LMQC and LMQI determine the value of the timeout during this leave
process (2 seconds with the default LMQC and LMQI).
On the Querier, the timeout during the leave process = LMQC * LMQI
On Snoopers, the timeout during the leave process =
LMQI from Querier * LMQC from Snooper
From Software Version 291-08, the command show igmpsnooping vlan={<vid>|all}
detail displays the timers for each individual port.
Manager Switch 1> show ip igmp
IGMP Protocol
------------------------------------------------------------------------
Status ........................... Enabled
Default Query Interval ........... 125 secs
Default Timeout Interval ......... 260 secs
Last Member Query Interval ....... 10 (1/10secs)
Last Member Query Count .......... 2
Robustness Variable .............. 2
Query Response Interval .......... 100 (1/10secs)
.
.
.