Configuring Fast Leave Processing - 3Com 4500G Family Configuration Manual

Follow these steps to configure simulated joining:
To do...
Enter system view
Enter Ethernet port/Layer 2
aggregate port view or port
group view
Configure simulated (*, G) or
(S, G) joining
Each simulated host is equivalent to an independent host. For example, when receiving an IGMP
query, the simulated host corresponding to each configuration responds respectively.
Unlike a static member port, a port configured as a simulated member host will age out like a
dynamic member port.

Configuring Fast Leave Processing

The fast leave processing feature allows the switch to process IGMP leave messages in a fast way.
With the fast leave processing feature enabled, when receiving an IGMP leave message on a port, the
switch immediately removes that port from the outgoing port list of the forwarding table entry for the
indicated group. Then, when receiving IGMP group-specific queries for that multicast group, the switch
will not forward them to that port.
In VLANs where only one host is attached to each port, fast leave processing helps improve bandwidth
and resource usage. However, if fast leave processing is enabled on a port to which more than one host
is attached, when one host leaves a multicast group, the other hosts attached to the port and interested
in the same multicast group will fail to receive multicast data for that group. Therefore, if the function of
dropping unknown multicast traffic is already enabled on the switch or in the VLANs, the fast leave
processing function should not be enabled.
Configuring fast leave processing globally
Follow these steps to configure fast leave processing globally:
To do...
Enter system view
Enter IGMP Snooping view
Enable fast leave processing
Use the command...
system-view
interface interface-type
interface-number
port-group manual port-group-name
igmp-snooping host-join
group-address [ source-ip
source-address ] vlan vlan-id
Use the command...
system-view
igmp-snooping
fast-leave [ vlan vlan-list ]
1-10
Remarks
—
Required
Use either approach
Required
Disabled by default
Remarks
—
—
Required
Disabled by default