Backup Interfaces - Avaya G250 Administration

Configuring WAN interfaces

Backup interfaces

You can configure backup relations between a pair of any Layer 2 serial interfaces. A backup
interface is activated when the primary interface fails. The backup interface is deactivated when
the primary interface is restored. A PPP session, frame relay interface, frame relay
sub-interface, Dialer interface, Fast Ethernet interface, or loopback interface can serve as a
backup interface to any other serial interface on the same module, including interfaces on
different serial ports.
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A frame relay interface in a primary or backup role overrides the role of its
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sub-interfaces.
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If the Fast Ethernet interface serving as a backup interface is configured as a
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DHCP client, it sends no DHCP packets. Therefore its IP address is not renewed
until it becomes the primary interface.
If the Fast Ethernet interface serving as a primary interface is configured as a
DHCP client, the expiration of the leases on its IP address or no reception of an
IP address does not cause activation of the backup interface.
Configurable activation and deactivation delays provide a damping effect on the backup
interface pair. This eliminates primary-to-backup switching in case of fluctuating underlying
Layer 2 interfaces. You can configure the following backup delays using the backup delay
command:
Failure delay — The time in seconds between the primary interface going down and
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the backup interface activation. Default = 0 seconds, maximum = 3600 seconds.
Secondary Disable delay — The time in seconds between the primary interface
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restoration and the backup interface deactivation. Default = 0 seconds, maximum = 3600
seconds. Both interfaces are active during this time to enable a smooth transition for the
routing protocols. To keep the backup interface active indefinitely, use never as the
secondary disable delay.
For example, you can use the following command to switch over immediately to the backup
interface in case of failure, and pause 60 seconds before reverting to the primary interface:
G350-001(super)# interface FastEthernet 10/2
G350-001(super-if:FastEthernet 10/2)# backup delay 0 60
Done!
G350-001(super-if:FastEthernet 10/2)#
The following rules govern the interface backup relations:
Each interface can have only one backup interface.
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A backup interface can serve as a backup for only one other interface.
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146 Administration for the Avaya G250 and Avaya G350 Media Gateways