Virtual Router Redundancy Protocol - NETGEAR FSM726E-100NAS Administration Manual

In this chapter, the following examples are provided:
• "Configure VRRP on a Master Router" on page 11-2
• "Configure VRRP on a Backup Router" on page 11-4
When an end station is statically configured with the address of the router that will handle its routed traffic,
a single point of failure is introduced into the network. If the router goes down, the end station is unable to
communicate. Since static configuration is a convenient way to assign router addresses, Virtual Router
Redundancy Protocol (VRRP) was developed to provide a backup mechanism.
VRRP eliminates the single point of failure associated with static default routes by enabling a backup router
to take over from a "master" router without affecting the end stations using the route. The end stations will
use a "virtual" IP address that will be recognized by the backup router if the master router fails. Participating
routers use an election protocol to determine which router is the master router at any given time. A given
port may appear as more than one virtual router to the network, also, more than one port on a 7000 Series
Managed Switch may be configured as a virtual router. Either a physical port or a routed VLAN may
participate.
Layer 3 Switch
acting as Router 1
Port 1/0/2
192.150.2.1
Virtual Router ID 20
Virtual Addr. 192.150.2.1
Figure 11-1

Virtual Router Redundancy Protocol

Layer 2 Switch
Hosts
v1.0, November 2008
Chapter 11
Layer 3 Switch
acting as Router 2
Port 1/0/4 VLAN
192.150.4.1
Virtual Router ID 20
Virtual Addr. 192.150.2.1
11-1