mld-snooping prompt-leave (VSI view)

Function

The mld-snooping prompt-leave command enables prompt leave.

The undo mld-snooping prompt-leave command disables prompt leave.

By default, prompt leave is disabled.

Format

mld-snooping prompt-leave [ group-policy { acl6-number | acl6-name acl6-name } ]

undo mld-snooping prompt-leave

Parameters

Parameter	Description	Value
group-policy	Configures a group policy to enable prompt leave for member interfaces of a specified or all multicast groups.	-
acl6-number	Specifies the number of an ACL6.	The value is an integer ranging from 2000 to 3999.
acl6-name acl6-name	Specifies the name of a named ACL6.	The value is a string of 1 to 64 case-sensitive characters without spaces. The value must start with a letter (a to z or A to Z, case sensitive).

Parameter

Description

Value

group-policy

Configures a group policy to enable prompt leave for member interfaces of a specified or all multicast groups.

acl6-number

Specifies the number of an ACL6.

The value is an integer ranging from 2000 to 3999.

acl6-name acl6-name

Specifies the name of a named ACL6.

The value is a string of 1 to 64 case-sensitive characters without spaces. The value must start with a letter (a to z or A to Z, case sensitive).

Views

VSI-AUTO view, VSI-BD view, VSI-DEFAULT view, VSI-STATIC view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
l2mc	write

Usage Guidelines

Usage Scenario

After receiving an MLD Done message for a multicast group from a host, a device enabled with prompt leave directly deletes the forwarding entry of the multicast group, without sending group-specific Query messages. If an interface is connected to only one host, the prompt leave mechanism can be used to shorten the response delay and release bandwidth resources in a timely manner.

If group-policy <acl6-number> or group-policy acl6-name <acl6-name> is not set, prompt leave will take effect for all multicast groups.

If group-policy <acl6-number> or group-policy acl6-name <acl6-name> is set, prompt leave will take effect for groups of which the MLD Done messages meet the permit clause of the ACL6.

If a multicast group meets the permit clause of the specified ACL6, the device deletes the member interface of the group immediately after receiving an MLD Done message of this group and notifies the upstream device of the user leave event.
If a multicast group does not meet the permit clause of the specified ACL6, the device notifies the upstream device of a user leave event after receiving an MLD Done message of a group. The upstream device can then send a group-specific Query message to learn whether members exist in the group.

Prerequisites

MLD snooping has been enabled globally and in the VLAN/VSI view.

Rules have been configured in the specified ACL6. By default, the ACL6 rule in which the action is permit applies to all multicast groups. To enable prompt leave for a multicast group, you need to run the rule (basic ACL6 view) deny source any or rule (advanced ACL6 view) deny source any command.

Configuration Impact

Do not enable prompt leave for a VLAN/VSI if a multicast member interface connects to multiple receiver hosts. If a member interface connects to multiple receivers, the prompt-leave-capable device will interrupt the multicast services of a group for all receivers of the group when a receiver leaves the multicast group.

If the mld-snooping prompt-leave command is run more than once in the same view, the latest configuration overrides the previous one.

Precautions

The

mld-snooping prompt-leave command fails to be run a VLAN view in any of the following conditions:

The VLAN is bound to a VSI.
The
mld-snooping prompt-leave command fails to be run in a VSI view in the following condition:
The VSI is bound to a BD.

Example

# Enable prompt leave for VSI vsi0 member interfaces of the multicast group FF18::1.

<HUAWEI> system-view
[~HUAWEI] acl ipv6 2008
[*HUAWEI-acl6-basic-2008] rule permit source ff18::1 64
[*HUAWEI-acl6-basic-2008] quit
[*HUAWEI] mld-snooping enable
[*HUAWEI] mpls
[*HUAWEI-mpls] quit
[*HUAWEI] mpls l2vpn
[*HUAWEI-l2vpn] quit
[*HUAWEI] vsi vsi0
[*HUAWEI-vsi-vsi0] pwsignal ldp
[*HUAWEI-vsi-vsi0-ldp] vsi-id 1
[*HUAWEI-vsi-vsi0-ldp] quit
[~HUAWEI] vsi vsi0
[*HUAWEI-vsi-vsi0] mld-snooping prompt-leave group-policy 2008