Configuring MLD On-Demand
Context
In a standard Multicast Listener Discovery (MLD) working process, a querier periodically sends Query messages and receives Multicast Listener Report and Done messages from the receiver hosts to learn information about group members. If group members on a network seldom change, you can configure MLD on-demand on the querier. After MLD on-demand is configured on the querier, the querier does not send Query messages, reducing MLD packets exchanged between the querier and receiver hosts. The querier maintains group membership according to requirements of receiver hosts without actively sending Query messages.
After MLD on-demand is configured, the switch:
- Does not send MLD Query messages through the interface.
- Generates MLD group entries that will never age out after receiving Multicast Listener Report messages.
- Deletes MLD group entries immediately when receiving Multicast Listener Done messages.
Procedure
- Run system-view
The system view is displayed.
- Run interface interface-type interface-number
The interface view is displayed.
- (Optional) On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
Only the S5720-EI, S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6730-H, S6730S-H, S6730-S, and S6730S-S support switching between Layer 2 and Layer 3 modes.
- Run mld on-demand
MLD on-demand is enabled on the interface. The interface then does not send MLD Query messages and MLD group entries on the interface are never aged.
By default, a querier does not maintain group memberships according to requirements of group members, and dynamic entries are aged out when the aging time expires.
If dynamic MLD entries have been generated on the querier, run the reset mld group command to clear these dynamic MLD entries before running the mld on-demand command.