mld on-demand

Function

The mld on-demand command enables the MLD on-demand function. This function enables a querier to maintain group memberships according to requirements of group members, without sending Query messages. After MLD on-demand is enabled on an interface, dynamic MLD entries on the interface will never age out.

The undo mld on-demand command restores the default configuration.

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.

Format

mld on-demand

undo mld on-demand

Parameters

None

Views

GE interface view, XGE interface view, MultiGE interface view, 25GE interface view, 40GE interface view, 100GE interface view, Eth-Trunk interface view, VLANIF interface view, loopback interface view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

In a standard MLD working process, a querier sends General Query messages periodically and collects group membership information based on received Multicast Listener Report and Done messages. Group members respond to every Query message they receive. The querier stops sending Query messages after MLD on-demand is configured, reducing MLD packets exchanged between the querier and receiver hosts.

The MLD on-demand function enables a querier to maintain group memberships based on Report messages sent from hosts, reducing traffic transmitted between the querier and receiver hosts.

Prerequisites

Layer 3 IPv6 multicast has been enabled using the multicast ipv6 routing-enable command in the system view.

Precautions

The mld on-demand command can be used on the querier only.
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.
After the mld on-demand command is executed on an interface:
- The interface no longer sends MLD Query messages.
- MLD group entries are generated after the interface receives Multicast Listener Report messages and will never age out.
- When the interface receives a Multicast Listener Done message, it deletes the corresponding MLD group entry.
The mld on-demand configuration of the VLANIF interface and the mld-snooping enable command in a VLAN are mutually exclusive.

Example

# Enable the MLD on-demand function on VLANIF100.

<HUAWEI> system-view
[HUAWEI] multicast ipv6 routing-enable
[HUAWEI] interface vlanif 100
[HUAWEI-Vlanif100] mld on-demand

# Enable the MLD on-demand function on GE0/0/1.

<HUAWEI> system-view
[HUAWEI] multicast ipv6 routing-enable
[HUAWEI] interface gigabitethernet 0/0/1
[HUAWEI-GigabitEthernet0/0/1] undo portswitch
[HUAWEI-GigabitEthernet0/0/1] mld on-demand