Brocade TurboIron 24X Series Configuration Guide - Manual (Page 898)

864 Brocade TurboIron 24X Series Configuration Guide
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Overview
Overview of VRRP
NOTE
VRRP support in the base Layer 3 code is the same as in the full Layer 3 code.
VRRP is a protocol that provides redundancy to routers within a LAN. VRRP allows you to provide
alternate router paths for a host without changing the IP address or MAC address by which the host
knows its gateway. Consider the situation shown in
Figure 111 .
FIGURE 111 Switch 1 is Host1 default gateway but is a single point of failure
Switch 1 as the host default gateway out of the subnet. If this interface goes down, Host1 is cut off
from the rest of the network. Switch 1 is thus a single point of failure for Host1 access to other
networks.
If Switch 1 fails, you could configure Host1 to use Switch 2. Configuring one host with a different
default gateway might not require too much extra administration. However, consider a more
realistic network with dozens or even hundreds of hosts per subnet; reconfiguring the default
gateways for all the hosts is impractical. It is much simpler to configure a VRRP virtual router on
Switch 1 and Switch 2 to provide a redundant path for the hosts.
Figure 112 shows the same example network shown in Figure 111 , but with a VRRP virtual router
configured on Switch 1 and Switch 2.
FIGURE 112 Switch 1 and Switch 2 are configured as a VRRP virtual router for redundant network
access for Host1