preempt enable

Function

The preempt enable command enables delayed switchback and also specifies a switchback delay for the master member interface in an Eth-Trunk interface in manual 1:1 master/backup mode.

The undo preempt enable command disables delayed switchback of the master member interface in an Eth-Trunk interface in manual 1:1 master/backup mode.

By default, delayed switchback of the master member interface in an Eth-Trunk interface in manual 1:1 master/backup mode is disabled.

Format

preempt enable [ delay delay-time | delay delay-time seconds | delay delay-time seconds milliseconds ]

undo preempt enable [ delay delay-time | delay delay-time seconds | delay delay-time seconds milliseconds ]

Parameters

Parameter	Description	Value
delay delay-time	Specifies a switchback delay for the master member interface in an Eth-Trunk interface in manual 1:1 master/backup mode.	The value is an integer ranging from 0 to 30, in minutes.The default value is 0, indicating that the master member interface becomes active immediately after it recovers.
seconds	Specifies a switchback delay for the master member interface.	The value is an integer ranging from 0 to 59, in seconds. The default value is 0.
milliseconds	Specifies a switchback delay for the master member interface.	The value is an integer ranging from 0 to 999, in milliseconds. The default value is 0.

Parameter

Description

Value

delay delay-time

Specifies a switchback delay for the master member interface in an Eth-Trunk interface in manual 1:1 master/backup mode.

The value is an integer ranging from 0 to 30, in minutes.The default value is 0, indicating that the master member interface becomes active immediately after it recovers.

seconds

Specifies a switchback delay for the master member interface.

The value is an integer ranging from 0 to 59, in seconds.

The default value is 0.

milliseconds

Specifies a switchback delay for the master member interface.

The value is an integer ranging from 0 to 999, in milliseconds.

The default value is 0.

Views

Eth-Trunk interface view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
trunk	write

Usage Guidelines

Usage Scenario

If the master member interface in an Eth-Trunk interface in manual 1:1 master/backup mode fails, it becomes inactive. If the master member interface recovers, it needs to become active again. To enable delayed switchback for the master member interface, run the preempt enable command.

If you want the master member interface to become active immediately after it recovers, you do not need to specify a switchback delay.
If you want the recovered master member interface to become active after a delay, run the preempt enable delay delay-time command to specify a switchback delay.
This command applies only to Eth-Trunk interfaces in manual 1:1 master/backup mode that are connected through intermediate devices.

Prerequisites

An Eth-Trunk interface has been configured to work in manual 1:1 master/backup mode using the mode manual backup command, and an Eth-Trunk member interface has been configured as the master interface using the port-master command.

Precautions

The preempt enable and inactive-port shutdown enable commands are mutually exclusive.

Example

# Enable delayed switchback for the master member interface in Eth-Trunk 10 that works in manual 1:1 master/backup mode and specify the switchback delay as 5 minutes.

<HUAWEI> system-view
[~HUAWEI] interface eth-trunk 10
[*HUAWEI-Eth-Trunk10] portswitch
[*HUAWEI-Eth-Trunk10] mode manual backup
[*HUAWEI-Eth-Trunk10] preempt enable delay 5