RFC 2281 (rfc2281) - Page 1 of 17

Cisco Hot Standby Router Protocol (HSRP)

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Network Working Group                                              T. Li
Request for Comments: 2281                              Juniper Networks
Category: Informational                                          B. Cole
                                                        Juniper Networks
                                                               P. Morton
                                                           Cisco Systems
                                                                   D. Li
                                                           Cisco Systems
                                                              March 1998


                Cisco Hot Standby Router Protocol (HSRP)

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (1998).  All Rights Reserved.

IESG Note

   This document reflects an existing deployed protocol.  The IETF does
   have a working group which is in the process of producing a standards
   track protocol to address the same issues.

Abstract

   The memo specifies the Hot Standby Router Protocol (HSRP).  The goal
   of the protocol is to allow hosts to appear to use a single router
   and to maintain connectivity even if the actual first hop router they
   are using fails.  Multiple routers participate in this protocol and
   in concert create the illusion of a single virtual router.  The
   protocol insures that one and only one of the routers is forwarding
   packets on behalf of the virtual router.  End hosts forward their
   packets to the virtual router.

   The router forwarding packets is known as the active router.  A
   standby router is selected to replace the active router should it
   fail. The protocol provides a mechanism for determining active and
   standby routers, using the IP addresses on the participating routers.
   If an active router fails a standby router can take over without a
   major interruption in the host's connectivity.  This memo also
   discusses the ARP, MAC address, and security issues with this
   protocol.



Li, et. al.                  Informational
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