Foundry NetIron M2404C and M2404F Metro Access Switches
Configuring Multicast Layer 2 (Rev. 03)
IGMP Snooping
© 2008 Foundry Networks, Inc.
Page 16 of 43
1.
The device sends a specific query for that group, with the response time field set to 1 second
(last-member interval);
2.
The device waits 1 second (last-member interval);
3.
If join is received, the device refreshes the group membership aging, and stops the procedure.
NOTE
This procedure is NOT performed when Immediate leave is enabled.
The default values are listed in
Table 8
.
Command Syntax
device-name
(config)#
ip igmp snooping router-timers
{
last-member <last-
member-interval>
|
query <query-interval>
|
responses <responses-time>
|
robustness
<robustness>
}
Argument Description
last-member
<last-member-
interval>
The expected response time, in seconds, for answering a specific query. The
range is <1-25>. The default value is 1 second.
The response time must be less than the query interval.
This value will be inserted in the response-time field of the specific query
packet generated by the device. Increasing the response time makes the
traffic less bursty, by spreading out host responses over a larger interval.
query <query-
interval>
The maximum time interval that the device waits after sending a group-
specific query to determine if hosts are still interested in a specific multicast
group. The range is <11-32762>. The default value is 125 seconds.
responses
<responses-
time>
The expected response time, in seconds, for answering a general query. The
range is <1-25>. The default value is 10 seconds.
This value will be inserted in the response-time field of the general query
packet generated by the device. Increasing the response time makes the
traffic less bursty, by spreading out host responses over a larger interval.
robustness
<robustness>
The number of specific query packets sent by the device. The value is
greater than 1. The range is <2-254>. The default value is 2 packets.
The Robustness Variable allows tuning for the expected packet loss. If a
subnet is expected to be lossy, the Robustness Variable may be increased.
Example
In the following example four specific queries will be sent every 30 seconds with response time set
to 15 seconds. If no join is received after 135 seconds, the Leave packet will be sent to the
Multicast router port.
device-name
(config)#
ip igmp snooping router-timers query 30
Query interval is 30 sec
device-name
(config)#
ip igmp snooping router-timers responses 15
device-name
(config)#
ip igmp snooping router-timers robustness 4