A first hop redundancy protocol (FHRP) is a computer networking protocol which is designed to protect the default gateway used on a

subnetwork A subnetwork or subnet is a logical subdivision of an IP network. Updated by RFC 6918. The practice of dividing a network into two or more networks is called subnetting. Computers that belong to the same subnet are addressed with an identical ...

by allowing two or more routers to provide backup for that address; 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 An Internet Protocol address (IP address) is a numerical label such as that is connected to a computer network that uses the Internet Protocol for communication.. Updated by . An IP address serves two main functions: network interface ident ...

, not just routers. Examples of such protocols include (in approximate order of creation): * Hot Standby Router Protocol (HSRP) -

Cisco Cisco Systems, Inc., commonly known as Cisco, is an American-based multinational digital communications technology conglomerate corporation headquartered in San Jose, California. Cisco develops, manufactures, and sells networking hardware, ...

's initial, proprietary standard developed in 1998 *

Virtual Router Redundancy Protocol The Virtual Router Redundancy Protocol (VRRP) is a computer networking protocol that provides for automatic assignment of available Internet Protocol (IP) routers to participating hosts. This increases the availability and reliability of routing p ...

(VRRP) - an open (albeit patent encumbered) standard protocol *

Common Address Redundancy Protocol The Common Address Redundancy Protocol or CARP is a computer networking protocol which allows multiple hosts on the same local area network to share a set of IP addresses. Its primary purpose is to provide failover redundancy, especially when us ...

(CARP) - patent-free unencumbered alternative to Cisco's HSRP developed in October 2003 * Extreme Standby Router Protocol (ESRP) - Extreme Networks' proprietary standard with fast failover and also

layer 2 The data link layer, or layer 2, is the second layer of the seven-layer OSI model of computer networking. This layer is the protocol layer that transfers data between nodes on a network segment across the physical layer. The data link layer pr ...

protection * Gateway Load Balancing Protocol (GLBP) - a more recent proprietary standard from Cisco that permits load balancing as well as redundancy * Routed Split multi-link trunking (R-SMLT) - an Avaya redundancy protocol *

NetScreen Redundancy Protocol NetScreen Technologies was an American technology company that was acquired by Juniper Networks for US$4 billion stock for stock in 2004. NetScreen Technologies developed ASIC-based Internet security systems and appliances that delivered high per ...

(NSRP) - a Juniper Networks proprietary router redundancy protocol providing load balancing *

Chassis Cluster Redundant Ethernet A chassis (, ; plural ''chassis'' from French châssis ) is the load-bearing framework of an artificial object, which structurally supports the object in its construction and function. An example of a chassis is a vehicle frame, the underpart ...

- a Juniper Networks proprietary Ethernet redundancy protocol, used on its SRX platform * Multi-active Gateway Protocol (MAGP) - a

Mellanox Mellanox Technologies Ltd. ( he, מלאנוקס טכנולוגיות בע"מ) was an Israeli-American multinational supplier of computer networking products based on InfiniBand and Ethernet technology. Mellanox offered adapters, switches, softwa ...

proprietary protocol based on VRRP that allows active-active operation

References

{{network-stub Internet protocols