– 687 –
18 Configuring Router Redundancy
Router redundancy protocols use a virtual IP address to support a primary router
and multiple backup routers. The backup routers can be configured to take over
the workload if the master router fails, or can also be configured to share the traffic
load. The primary goal of router redundancy is to allow a host device which has
been configured with a fixed gateway to maintain network connectivity in case the
primary gateway goes down.
This switch supports the Virtual Router Redundancy Protocol (VRRP). VRRP allows
you to specify the interface of one of the routers participating in the virtual group
as the address for the master virtual router, or to configure an arbitrary address for
the virtual master router. VRRP then selects the backup routers based on the
specified virtual router priority.
Router redundancy can be set up in any of the following configurations. These
examples use the address of one of the participating routers as the master router.
When the virtual router IP address is not a real address, the master router is selected
based on priority. When the priority is the same on several competing routers, then
the router with the highest IP address is selected as the master.
Figure 454: Master Virtual Router with Backup Routers
Master Router
Backup Router
Virtual Router (VR23)
VRIP = 192.168.1.3
VRID 23
IP(R1) = 192.168.1.3
IP(VR23) = 192.168.1.3
VR Priority = 255
VRID 23
IP(R2) = 192.168.1.5
VRIP(VR23) = 192.168.1.3
VR Priority = 100
To Next Page
Loading...
Need help?
General