Interface Backup Overview - Huawei AR2200-S Series Configuration Manual

Huawei AR2200-S Series Enterprise Routers
Configuration Guide - Reliability

1.1 Interface Backup Overview

Interface backup ensures smooth services. When an interface on a router is faulty or the traffic
is heavy, interface backup allows the router to quickly switch services on the faulty interface to
other available interfaces.
Introduction to Interface Backup
Important data services need to be smoothly transmitted to the destination network segment. If
data services are transmitted on one link, they will be interrupted if the link is faulty. Interface
backup improves reliability of data service transmission. The interface backup function allows
interfaces of a router to back up each other. The interface working in active mode is the primary
interface, and interfaces working in standby mode are backup interfaces. The link connected to
the primary interface is the primary link, and the links connected to backup interfaces are backup
links. Most backup links are low-bandwidth or low-cost links, such as dialup links. Ethernet
links can also be used as backup links. When an interface is faulty or the traffic is heavy, traffic
can be quickly switched to a backup interface. The backup interface transmits or loads balance
service traffic.
Interface Backup Elements
The interface backup function involves the following interfaces:
l
l
Interface Types Supported by AR2200-S
The primary interfaces can be a Layer 3 Ethernet interface, Layer 3 Ethernet subinterface, dialer
interface, ATM interface, BRI interface, Async interface, cellular interface, MP-group interface,
MFR interface, MFR subinterface, serial interface, or serial subinterface.
The backup interfaces can be a Layer 3 Ethernet interface, Layer 3 Ethernet subinterface, dialer
interface, ATM interface, BRI interface, Async interface, cellular interface, PON interface, MP-
group interface, MFR interface, MFR subinterface, serial interface, or serial subinterface.
Issue 01 (2012-01-06)
Primary interface
The primary interface transmits services.
Backup interface
A backup interface is a backup of the primary interface.
NOTE
l Only WAN-side interfaces can function as the primary or backup interfaces of routers. The primary
and backup interfaces of a router can be of different types.
l A primary interface has a maximum of three backup interfaces. When the primary interface is faulty,
backup interfaces are selected based on priority in descending order.
l A backup interface can be used as the backup of only one primary interface.
l A maximum of 10 primary interfaces can be configured on a device simultaneously.
l A dialup interface can be a dialer interface, a physical interface bound to the dialer interface, or a
physical interface configured with Dialer Control Center (DCC) parameters.
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