FHRP

First Hop Redundancy Protocol is designed to protect the default gateway used on a subnet by allowing 2 or more router to provide backup to that address

Introduction

High availability is critical in most environments. In this example there is only gateway which is a single point of failure.

Using multiple routers of multi-layer switches can provide Layer 3 redundancy for the hosts, however this L3 redundancy must be TRANSPARENT (no multiple default-gateways) to the hosts

Transparent Layer-3 Redundancy

Cisco supports 3 FHRP's

• HSRP (Hot Standby Routing Protocol)

• VRRP (Virtual Router Redundancy Protocol)

• GLBP (Gateway Load Balancing Protocol)