First Hop Redundancy: Part 1 of 4

Consider a network with the following setup: a collection of workstations, a switch, and a router.  The router's IP address is configured as the default gateway for all the workstations.  What will happen if the router dies?  The workstations will have no way of accessing services outside the subnet.

That is the problem we want to address.  We need a solution that provides a first hop redundancy for these workstations.  The technologies available to solve this problem are HSRP, VRRP, and GLBP.

These protocols allow you to configure multiple routers to work together to provide redundancy for the default gateway.  In the next few articles, we will examine each of these protocols.  We will discuss how they work, what problems they address, and what their caveats are.