igmp-snooping require-router-alert
Function
The igmp-snooping require-router-alert command configures the wireless access controller to drop the IGMP messages without the Router-Alert option in the IP header received from a VLAN.
The undo igmp-snooping require-router-alert command restores the default configuration.
By default, the wireless access controller does not check the Router-Alert option of IGMP messages and processes all the received IGMP messages, regardless of whether they carry the Router-Alert option in the IP header.
Usage Guidelines
Usage Scenario
The Router-Alert option identifies the protocol messages that need to be processed by upper-layer routing protocols.
By default, the wireless access controller does not check whether IGMP messages contain the Router-Alert option and sends all the IGMP messages to the upper-layer routing protocol. Discarding IGMP messages without the Router-Alert option improves device performance, reduces cost, and enhances security of the upper-layer routing protocol. After the igmp-snooping require-router-alert command is executed, the wireless access controller checks each IGMP message for the Router-Alert option and discards those IGMP messages without this option.
Prerequisites
IGMP snooping has been enabled globally using the igmp-snooping enable (system view) command.
Precautions
The configuration takes effect only after you run the igmp-snooping enable (VLAN view) command to enable IGMP snooping in the VLAN.
Example
# Configure the wireless access controller to forward only the IGMP messages with the Router-Alert option in the IP header received from VLAN 3.
<AC6605> system-view [AC6605] igmp-snooping enable [AC6605] vlan 3 [AC6605-vlan3] igmp-snooping enable [AC6605-vlan3] igmp-snooping require-router-alert
