Cisco Hot Standby Router Protocol (HSRP) (RFC2281)
Original Publication Date: 1998-Mar-01
Included in the Prior Art Database: 2000-Sep-13
Publishing Venue
Internet Society Requests For Comment (RFCs)
Related People
T. Li: AUTHOR [+3]
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.
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.
TABLE OF CONTENTS
1 Introduction .............................................. 2
2 Conditions of Use ......................................... 3
3 Scope ..................................................... 4
3.1 Terminology ............................................... 4
4 Definitions ............................................... 4
5 Protocol .................................................. 4
5.1 Packet formats ..........................