Hot Standby Router Protocol
- Hot Standby Router Protocol
Hot Standby Router Protocol (HSRP) is a Cisco proprietary redundancy protocol for establishing a fault-tolerant default gateway, and has been described in detail in RFC 2281. The Virtual Router Redundancy Protocol (VRRP) is a standards-based alternative to HSRP defined in IETF standard RFC 3768. The two technologies are similar in concept, but not compatible.
The protocol establishes a framework between network routers in order to achieve default gateway failover if the primary gateway should become inaccessible, in close association with a rapid-converging routing protocol like EIGRP or OSPF. By multicasting packets, HSRP sends its hello messages to the multicast address 224.0.0.2 (all routers) using UDP port 1985, to other HSRP-enabled routers, defining priority between the routers. The primary router with the highest configured priority will act as a "virtual" router with its own IP and MAC address,which the hosts on the local segment will be configured to use as a gateway to the destination in question. If the primary router should fail, or the link to the destination drop, the router with the next-highest priority would take over communications through alternative routes within seconds, without major interruption to network connectivity.
HSRP and VRRP are not routing protocols as they do not advertise IP routes or affect the routing table in any way.
HSRP and VRRP on some routers have the ability to trigger a failover if one or more interfaces on the router go down. This can be useful for dual branch routers each with a single serial link back to the head end. If the serial link of the primary router goes down, you would want the backup router to take over the primary functionality and thus retain connectivity to the head end.
ee also
* Virtual Router Redundancy Protocol - standards-based alternative to HSRP
* Gateway Load Balancing Protocol - Cisco proprietary router redundancy solution providing load balancing
* Common Address Redundancy Protocol - non-proprietary patent-free and unrestricted alternative to HSRP and VRRP
External links
* [http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a0080094a91.shtml Cisco: HSRP Features]
* [http://www.netcraftsmen.net/welcher/papers/hsrp.htm Netcraftsmen: HSRP by Peter J. Welcher]
* [http://www.szukalak.ovh.org: HSRP Protocol Configuration by Szukala K.]
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Hot Standby Router Protocol — (HSRP) est un protocole propriétaire de Cisco implémenté sur les routeurs et les commutateurs de niveau 3 permettant une continuité de service. HSRP est principalement utilisé pour assurer la disponibilité de la passerelle par défaut dans un sous … Wikipédia en Français
Hot Standby Router Protocol — HSRP (Hot Standby Router Protocol) Familie: Internetprotokollfamilie Einsatzgebiet: Steigerung der Verfügbarkeit von Gateways HSRP im TCP/IP Protokollstapel Anwendung HSRP Transport … Deutsch Wikipedia
Hot Standby Routing Protocol — Hot Standby Router Protocol Le protocole Hot Standby Router Protocol (HSRP) est un protocole propriétaire de Cisco implémenté sur les routeurs permettant une continuité de service. Chaque routeur utilisant le protocole HSRP appartient à un groupe … Wikipédia en Français
Virtual Router Redundancy Protocol — VRRP (Virtual Router Redundancy Protocol) Familie: Internetprotokollfamilie Einsatzgebiet: Hochverfügbarkeit von Routern VRRP im TCP/IP Protokollstapel Vermittlung VRRP IP … Deutsch Wikipedia
Common address redundancy protocol — ou CARP est un protocole permettant à un groupe d hôtes sur un même segment réseau de partager une adresse IP. Le nom CARP est en fait un sigle signifiant « Common Address Redundancy Protocol » (Protocole Commun De Redondance D Adresse) … Wikipédia en Français
Common Address Redundancy Protocol — ou CARP est un protocole permettant à un groupe d hôtes sur un même segment réseau de partager une adresse IP. Le nom CARP est en fait un sigle signifiant « Common Address Redundancy Protocol » (Protocole Commun De Redondance D Adresse) … Wikipédia en Français
Common Address Redundancy Protocol — The Common Address Redundancy Protocol or CARP is a protocol which allows multiple hosts on the same local network to share a set of IP addresses. Its primary purpose is to provide failover redundancy, especially when used with firewalls and… … Wikipedia
Gateway Load Balancing Protocol — est un protocole propriétaire Cisco qui permet de faire de la redondance ainsi que de la répartition de charge sur plusieurs routeurs utilisant une seule adresse IP virtuelle, mais plusieurs adresses MAC virtuelles. Le protocole GLBP élit un… … Wikipédia en Français
Virtual Router Redundancy Protocol — (VRRP) is a non proprietary redundancy protocol described in RFC 3768 designed to increase the availability of the default gateway servicing hosts on the same subnet. This increased reliability is achieved by advertising a virtual router (an… … Wikipedia
Virtual Router Redundancy Protocol — (VRRP) es un protocolo de redundancia no propietario definido en el RFC 3768 diseñado para aumentar la disponibilidad de la puerta de enlace por defecto dando servicio a máquinas en la misma subred. El aumento de fiabilidad se consigue mediante… … Wikipedia Español
