3Com Switch 8800 Family Firewall Module Configuration and Command Reference Guide

RELIABILITY OVERVIEW

The content below applies to the Firewall and IPsec modues, so the command

views in this document apply to the modules and not the Switch 8800 Family

switches.

Introduction to

Reliability

During communication, any software or hardware error, network device or line

fault for example, may disrupt the connection, causing transmission failure. To

avoid these situations, Comware provides, virtual router redundancy protocol

(VRRP) and hot backup technologies to ensure availability of a backup scheme

when faults occur. This guarantees smooth communication, and makes the

network more robust and reliable.

VRRP improves reliability of connections to the outside networks and as such, is

well suited to multicast or broadcast LANs such as Ethernet. Multiple routers can

form a standby group or a virtual router, acting as the only egress gateway for the

local network. These routers, however, are transparent to the local network. In the

standby group, a router is engaged in packet forwarding, a backup router is ready

for replacing the active router, and the other routers are listening. In case the

active router fails, the backup router would take over and the other routers would

elect from them a new backup router. This improves reliability, allowing the local

hosts to continue their operation without any modification.