> For the complete documentation index, see [llms.txt](https://cisco.microcisco.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cisco.microcisco.com/icnd-1/routing/fhrp.md).

# 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.

![](https://4011257951-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LtfmTuncdFr6DnNyt_b%2F-MJagxfWDOPb8pMFKNV3%2F-MJahbfRM7SRHwi_TMrw%2Fimage.png?alt=media\&token=191da87a-00be-484f-9bd9-9200fa633910)

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

![](https://4011257951-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LtfmTuncdFr6DnNyt_b%2F-MJagxfWDOPb8pMFKNV3%2F-MJahlMTmwjWckRYNwEz%2Fimage.png?alt=media\&token=68acd430-a7e3-4701-8501-7c36ed4e7d45)

## Transparent Layer-3 Redundancy

Cisco supports 3 FHRP's

* HSRP (Hot Standby Routing Protocol)
* VRRP (Virtual Router Redundancy Protocol)
* GLBP (Gateway Load Balancing Protocol)