The prompt-leave command enables the fast leave function globally. After receiving a Leave message for a group, the device immediately deletes the group entry, without sending an IGMP Group-Specific Query message or IGMP Group-and-Source-Specific Query message.
The undo prompt-leave command restores the default configuration.
By default, a multicast device sends an IGMP Group-Specific Query message or IGMP Group-and-Source-Specific Query message after receiving a Leave message from a host.
| Parameter | Description | Value |
|---|---|---|
| group-policy | Specifies a group policy that controls the range of groups to which the fast leave takes effect. | - |
| acl-number | Specifies the number of a basic or advanced ACL. This list specifies the range of multicast groups. | The number of a basic ACL is an integer that ranges from 2000 to 2999. The number of an advanced ACL ranges from 3000 to 3999. |
Usage Scenario
In most cases, after receiving a Leave message of a group or source-specific group, a multicast device sends an IGMP Group-Specific Query message or IGMP Group-and-Source-Specific Query message to check whether this group has other members. To minimize the response delay and save network bandwidth, configure fast leave on multicast devices. This function enables a multicast device to delete a group or source/group entry immediately after receiving a Leave message, without sending an IGMP Group-Specific Query message or IGMP Group-and-Source-Specific Query message.
Prerequisites
IP multicast routing has been enabled using the multicast routing-enable command.
Precautions
IGMP fast leave applies only to IGMPv2 and IGMPv3.
This command functions in the same way as the igmp prompt-leave command used in the interface view, except that the configuration in the IGMP view is globally valid, whereas the configuration in the interface view is valid only for the specified interface. The configuration in the interface view takes precedence over the configuration in the IGMP view. The configuration in the IGMP view is used only when the configuration in the interface view is not done.
<HUAWEI> system-view [HUAWEI] multicast routing-enable [HUAWEI] igmp [HUAWEI-igmp] prompt-leave
<HUAWEI> system-view [HUAWEI] multicast routing-enable [HUAWEI] acl number 2000 [HUAWEI-acl-basic-2000] rule permit source 225.1.0.0 0.0.255.255 [HUAWEI-acl-basic-2000] quit [HUAWEI] igmp [HUAWEI-igmp] prompt-leave group-policy 2000