Vrrp Overview; Vrrp Features Supported By The Ar2200-S - Huawei AR2200-S Series Configuration Manual

Huawei AR2200-S Series Enterprise Routers
Configuration Guide - Reliability

2.1 VRRP Overview

The Virtual Router Redundancy Protocol (VRRP) groups multiple routers into one virtual router,
and sets the default gateway address as the IP address of the virtual router.
Generally, all hosts on a network are configured with the same default route to an egress gateway.
These hosts send all packets whose destination addresses are not on the local network segment
to the default egress gateway, such as Router A in
the hosts and external networks to communicate. If the egress gateway is Down, all hosts using
this gateway fail to communicate with external networks.
Figure 2-1 LAN default gateway
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A common method to improve the system reliability is to deploy multiple egress gateways. In
addition, a mechanism for selecting one of routes to these gateways is required.
VRRP is a fault-tolerant protocol defined in RFC 3768. VRRP allows the hosts to select one of
routes to multiple egress gateways by separating logical devices from physical devices.
On a LAN (for example, an Ethernet) with multicast and broadcast capabilities, VRRP uses
logical gateways to provide high availability for transmission links, preventing a gateway failure
from interrupting services, without changing the configuration of routing protocols.

2.2 VRRP Features Supported by the AR2200-S

VRRP features include the VRRP backup group in master/backup mode, VRRP backup group
in load balancing mode, interface status tracking, virtual IP address ping, and VRRP security
authentication.
Master/Backup Mode
In master/backup mode, a VRRP backup group consists of a master router and multiple backup
routers. Different routers have different priorities in this backup group. The router with the
highest priority serves as the master router.
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Issue 01 (2012-01-06)
Gateway:10.0.0.1
Gateway:10.0.0.1
Gateway:10.0.0.1
The master router undertakes all the services normally.
The backup routers undertake the services only when the master router fails.
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Figure
10.0.0.1/24
RouterA
Ethernet
2 VRRP Configuration
2-1. The default egress gateway allows
Network
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