CISCO IOS in a Nutshell

Name

backup — interface

Synopsis

backup interface interface
no backup interface interface

backup delay {enable-time | never} {disable-time | never}
no backup delay {enable-time | never} {disable-time | never}

backup load {enable-load | never} {disable-load | never}
no backup load {enable-load | never} {disable-load | never}

Configures

A backup interface

Default

None

Description

This family of commands configures a backup interface for the current interface. The first command, backup interface, specifies the interface to be used as the backup. The backup interface is activated when the primary interface goes down or reaches the load specified by the backup load command.

The backup delay command specifies how long the router should wait before activating (enable-time) or deactivating (disable-time) the backup interface. Both enable-time and disable-time are in seconds. Use of the backup delay command allows you to prevent routing instability if you have an intermittent interface. The keyword never, when used for the enable-time parameter, prevents the backup interface from being activated; when used for the disable-time parameter, it prevents the backup interface from being deactivated once it has been activated.

The backup load command specifies the load on the primary interface at which the backup interface should be activated (enable-load) or deactivated (disable-load). The load is expressed as a percentage of the primary interface’s maximum capacity. The keyword never, when used for the ...