The mld-snooping require-router-alert command configures interfaces in a VLAN/VSI to discard MLD messages that do not carry the Router-Alert option in IP headers.
The undo mld-snooping require-router-alert command restores the default configuration.
By default, the MLD messages accepted by a device from a VLAN/VSI do not need to carry the Router Alert option.
Usage Scenario
Router-Alert is a mechanism used to identify protocol messages. Messages carrying the Router-Alert option are delivered to the routing protocol layer for processing.
By default, devices do not check whether messages carry Router-Alert options for the sake of compatibility, and send all MLD messages to the upper layer for processing. To improve device performance, reduce costs, and ensure protocol security, run the mld-snooping require-router-alert command to configure a device to discard MLD messages that do not carry Router-Alert options. After the command is run, the device checks whether a received MLD message carries the Router-Alert option and discards the message if it does not carry the Router-Alert option.Prerequisites
MLD snooping has been enabled using the mld-snooping enable command.
Precautions
The
mld-snooping require-router-alert command fails to be run in a VLAN view in any of the following conditions:<HUAWEI> system-view [~HUAWEI] mld-snooping enable [*HUAWEI] mpls [*HUAWEI-mpls] quit [*HUAWEI] mpls l2vpn [*HUAWEI-l2vpn] quit [*HUAWEI] vsi vsi1 [*HUAWEI-vsi-vsi1] pwsignal ldp [*HUAWEI-vsi-vsi1-ldp] vsi-id 200 [*HUAWEI-vsi-vsi1-ldp] quit [*HUAWEI-vsi-vsi1] mld-snooping require-router-alert