Brocade 6910 Ethernet Access Switch Configuration Guide (Supporting R2.2.0.0) - Manual (Page 504)

448 Brocade 6910 Ethernet Access Switch Configuration Guide
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IGMP Snooping
ip igmp snooping router-port-expire-time
This command configures the querier time out. Use the no form to restore the default.
Syntax
ip igmp snooping router-port-expire-time seconds
no ip igmp snooping router-port-expire-time
seconds - The time the switch waits after the previous querier stops before it considers it
to have expired. (Range: 1-65535; Recommended Range: 300-500)
Default Setting
300 seconds
Command Mode
Global Configuration
Example
The following shows how to configure the time out to 400 seconds:
Console(config)#ip igmp snooping router-port-expire-time 400
Console(config)#
ip igmp snooping tcn-flood
This command enables flooding of multicast traffic if a spanning tree topology change notification
(TCN) occurs. Use the no form to disable flooding.
Syntax
[no] ip igmp snooping tcn-flood
Default Setting
Disabled
Command Mode
Global Configuration
Command Usage
• When a spanning tree topology change occurs, the multicast membership information learned
by the switch may be out of date. For example, a host linked to one port before the topology
change (TC) may be moved to another port after the change. To ensure that multicast data is
delivered to all receivers, by default, a switch in a VLAN (with IGMP snooping enabled) that
receives a Bridge Protocol Data Unit (BPDU) with the TC bit set (by the root bridge) will enter
into “multicast flooding mode” for a period of time until the topology has stabilized and the
new locations of all multicast receivers are learned.
• If a topology change notification (TCN) is received, and all the uplink ports are subsequently
deleted, a time out mechanism is used to delete all of the currently learned multicast
channels.
• When a new uplink port starts up, the switch sends unsolicited reports for all current learned
channels out through the new uplink port.