Brocade FastIron Ethernet Switch IP Multicast Configuration Guide - Manual (Page 25)

Configuring report control
A device in passive mode forwards reports and leave messages from clients to the upstream router
ports that are receiving queries.
You can configure report control to rate-limit report forwarding within the same group to no more than
once every 10 seconds. This rate-limiting does not apply to the first report answering a group-specific
query.
NOTE
This feature applies to IGMP V2 only. The leave messages are not rate limited.
IGMP V2 membership reports of the same group from different clients are considered to be the same
and are rate-limited.
Use the ip multicast report-control command to alleviate report storms from many clients answering
the upstream router query.
device(config)#ip multicast report-control
Syntax: [no] ip multicast-report-control
The original command, ip igmp-report-control , has been renamed to ip multicast report-control .
The original command is still accepted; however, it is renamed when you configure a show
configuration command.
Modifying the wait time before stopping traffic when receiving a leave
message
You can define the wait time before stopping traffic to a port when a leave message is received. The
device sends group-specific queries once per second to ask if any client in the same port still needs this
group. Due to internal timer granularity, the actual wait time is between n and (n+1) seconds (n is the
configured value).
device(config)#ip multicast leave-wait-time 1
Syntax: [no] ip multicast leave-wait-timenum
num is the number of seconds from 1 through 5. The default is 2 seconds.
Modifying the multicast cache age time
You can set the time for an mcache to age out when it does not receive traffic. The traffic is hardware
switched. One minute before aging out an mcache, the device mirrors a packet of this mcache to CPU
to reset the age. If no data traffic arrives within one minute, this mcache is deleted. A lower value
quickly removes resources consumed by idle streams, but it mirrors packets to CPU often. A higher
value is recommended only data streams are continually arriving.
device(config)#ip multicast mcache-age 180
Syntax: [no] ip multicast mcache-age num
num is the number of seconds from 60 through 3600. The default is 60 seconds.
Configuring report control
FastIron Ethernet Switch IP Multicast Configuration Guide 23
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