H3C Technologies H3C WX3000E Series Wireless Switches - Manual (Page 20)

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To avoid this situation, you can enable simulated joining on a port of the AC. Namely, you configure the
port as a simulated member host for a multicast group. When the simulated member host receives an
IGMP query, it gives a response. Therefore,, the AC can continue receiving multicast data.
A simulated host acts like a real host in the following ways:
• When a port is configured as a simulated member host, the AC sends an unsolicited IGMP report
through the port, and can respond to IGMP general queries with IGMP reports through the port.
• When the simulated joining function is disabled on a port, the AC sends an IGMP leave message
through the port.
To configure simulated joining:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter Layer 2 Ethernet
interface view, Layer 2
aggregate interface view, or
port group view.
• Enter Layer 2 Ethernet interface view or
Layer 2 aggregate interface view:
interface interface-type interface-number
• Enter port group view:
port-group manual port-group-name
Use either approach.
3. Configure simulated joining. igmp-snooping host-join group-address
[ source-ip source-address ] vlan vlan-id
Not configured by default.
NOTE:
Unlike a static member port, a port that you configure as a simulated member host ages out like a dynamic
member port.
Configuring IGMP snooping fast-leave processing
The IGMP snooping fast-leave processing feature enables the AC to process IGMP leave messages
quickly. With the IGMP snooping fast-leave processing feature enabled, when the AC receives an IGMP
leave message on a port, it immediately removes that port from the outgoing port list of the forwarding
entry for the indicated group. Then, when the AC receives IGMP group-specific queries for that multicast
group, it does not forward them to that port.
In VLANs where only one host is attached to each port, IGMP snooping fast-leave processing helps
improve bandwidth and resource usage. However, if IGMP snooping fast-leave processing is enabled on
a port that connects to more than one host, 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 AC or
in the VLANs, IGMP snooping fast-leave processing function should not be enabled.
Configuring IGMP snooping fast-leave processing globally
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter IGMP-snooping view. igmp-snooping N/A
3. Enable IGMP snooping
fast-leave processing.
fast-leave [ vlan vlan-list ] Disabled by default