3Com Switch 7750 Configuration Guide

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VRRP CONFIGURATION
VRRP Overview Virtual router redundancy protocol (VRRP) is a fault-tolerant protocol.
As shown in Figure 141, in general,
■ A default route (for example, the next hop address of the default route is
10.100.10.1, as shown in the following figure) is configured for every host on a
network.
■ The packets destined to the external network segments and sourced from
these hosts go through the default routes to the Layer 3 Switch, implementing
communication between these hosts and the external network.
■ If Switch fails, all the hosts on this segment taking Switch as the next-hop
through the default routes are cut off from the external network.
Figure 141 LAN Networking
VRRP, designed for LANs with multicast and broadcast capabilities (such as
Ethernet), settles the problem caused by switch failures.
VRRP combines a group of LAN switches, including a master switch and several
backup switches, into a virtual router, or a backup group.
Host 1
Ethernet
Switch
Network
Host 2 Host 3
10.100.10.7 10.100.10.910.100 .10.8
10.100 .10.1