First hop redundancy protocols (FHRP) are a category of networking protocols designed to protect the default gateway used on a subnetwork by allowing two or more routers to provide backup for that address.[1][2][3] In the event of failure of an active router, the backup router will take over the address, usually within a few seconds. In practice, such protocols can also be used to protect other services operating on a single IP address, not just routers.
Examples of such protocols include (in approximate order of creation):
The term First Hop Redundancy Protocol (FHRP) refers to the category of protocols that enable hosts to take advantage of redundant routers in a subnet.