mld-snooping prompt-leave

Function

The mld-snooping prompt-leave command enables the fast leave function in a VLAN so that member ports in the VLAN can fast leave multicast groups.

The undo mld-snooping prompt-leave command disables the fast leave function in a VLAN.

By default, the fast leave function is disabled in a VLAN.

Format

mld-snooping prompt-leave [ group-policy acl6-number ]

undo mld-snooping prompt-leave

Parameters

Parameter	Description	Value
group-policy acl6-number	Allows member ports to fast leave the multicast groups matching an ACL6. acl6-number specifies the number of an ACL6. A basic or advanced ACL6 can be used.	The value is an integer that ranges from 2000 to 3999.

Views

VLAN view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

The fast leave function enables the switch to delete the multicast forwarding entry of a multicast group from an interface immediately after the interface receives a Done message for the group. This function saves bandwidth and system resources because the switch does not need to wait until the aging timer of the interface expires.

Prerequisites

MLD snooping has been enabled globally using the mld-snooping enable command.

Precautions

When an interface has more than one receiver connected, enabling the fast leave function interrupts multicast traffic of the other receivers in the multicast group. It is recommended that you enable this function only on interfaces with one receiver.

The configuration takes effect only when both the following conditions are met:

MLD snooping is enabled in the VLAN using the mld-snooping enable command.
If you do not specify group-policy when configuring the fast leave function, this function takes effect for all groups. To specify a group policy in the command, create an ACL and configure rules for the ACL before running the command. For details about ACL configuration commands, see ACL Configuration Commands in "Security Commands."

Example

# Allow member ports in VLAN 2 to fast leave all multicast groups.

<HUAWEI> system-view
[HUAWEI] mld-snooping enable
[HUAWEI] vlan 2
[HUAWEI-vlan2] mld-snooping enable
[HUAWEI-vlan2] mld-snooping prompt-leave

# Allow member ports in VLAN 3 to fast leave multicast group 0xff13::0001:0002.

<HUAWEI> system-view
[HUAWEI] mld-snooping enable
[HUAWEI] acl ipv6 number 2000
[HUAWEI-acl6-basic-2000] rule permit source ff13::0001:0002 128
[HUAWEI-acl6-basic-2000] quit
[HUAWEI] vlan 3
[HUAWEI-vlan3] mld-snooping enable
[HUAWEI-vlan3] mld-snooping prompt-leave group-policy 2000

# Prevent member ports in VLAN 3 from fast leaving multicast group 0xff13::0001:0002.

<HUAWEI> system-view
[HUAWEI] mld-snooping enable
[HUAWEI] acl ipv6 number 2000
[HUAWEI-acl6-basic-2000] rule deny source ff13::0001:0002 128
[HUAWEI-acl6-basic-2000] quit
[HUAWEI] vlan 3
[HUAWEI-vlan3] mld-snooping enable
[HUAWEI-vlan3] mld-snooping prompt-leave group-policy 2000