Configuration Guide User guide

FastIron Configuration Guide 1651
53-1002494-02
VRRP and VRRP-E overview
Switch 1 is 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’s 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 185 shows the same example network shown in Figure 184, but with a VRRP virtual router
configured on Switch 1 and Switch 2.
FIGURE 185 Switch 1 and Switch 2 configured as VRRP virtual routers for redundant network access for Host1
The dashed box in Figure 185 represents a VRRP virtual router. When you configure a virtual
router, one of the configuration parameters is the virtual router ID (VRID), which can be a number
from 1 through 255. In this example, the VRID is 1.
NOTE
You can provide more redundancy by also configuring a second VRID with Switch 2 as the Owner and
Switch 1 as the Backup. This type of configuration is sometimes called Multigroup VRRP.
Internet
or
enterprise Intranet
Internet
or
enterprise Intranet
Host1
Default Gateway
192.53.5.1
192.53.5.1
e 1/6
e 1/5
192.53.5.3
e 3/2
e 2/4
VRID1
Switch1 = Master
IP address = 192.53.5.1
MAC address = 00-00-5E-00-01-01
Priority = 255
VRID1
Switch2 = Backup
IP address = 192.53.5.1
MAC address = 00-00-5E-00-01-01
Priority = 100
Owner
Switch1
Switch2