3com 3.01.01 Benutzerhandbuch

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R
ELIABILITY
This chapter covers the following topics:
VRRP Overview
Virtual Router Redundancy Protocol (VRRP) is a fault-tolerant protocol. In general, 
a default route, for example, 10.100.10.1 in Figure 1, is configured for every host 
on a network, so that packets destined for another network segment go through 
the default route to Layer 3 Switch1, implementing communication between the 
host and the external network. If Switch1 is down, all the hosts on this segment 
have Switch1 as the next-hop for the default route and are disconnected from the 
external network.
Figure 1   LAN Networking
VRRP, which is designed for LANs with multicast and broadcast capabilities (such 
as Ethernet) settles this problem. Figure 2 illustrates the implementation principal 
of VRRP. VRRP combines a group of LAN switches, including a master and several 
backups, into a virtual router, or backup group.
Internet
Switch
10.100.10.1
Ethernet
10.100.10.7
10.100.10.8
10.100.10.9
Host 1
Host 2
Host 3