Virtual Router Redundancy Protocol (VRRP)
RFC 3768

Document Type RFC - Draft Standard (April 2004; No errata)
Obsoleted by RFC 5798
Obsoletes RFC 2338
Last updated 2013-03-02
Stream IETF
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Stream WG state (None)
Consensus Unknown
Document shepherd No shepherd assigned
IESG IESG state RFC 3768 (Draft Standard)
Telechat date
Responsible AD Alex Zinin
IESG note Implementation report available at
http://www.ietf.org/IESG/Implementations/rfc-2338-implementation.txt
Send notices to <radia.perlman@sun.com>, <Mukesh.Gupta@nokia.com>
Network Working Group                                     R. Hinden, Ed.
Request for Comments: 3768                                         Nokia
Obsoletes: 2338                                               April 2004
Category: Standards Track

               Virtual Router Redundancy Protocol (VRRP)

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2004).  All Rights Reserved.

Abstract

   This memo defines the Virtual Router Redundancy Protocol (VRRP).
   VRRP specifies an election protocol that dynamically assigns
   responsibility for a virtual router to one of the VRRP routers on a
   LAN.  The VRRP router controlling the IP address(es) associated with
   a virtual router is called the Master, and forwards packets sent to
   these IP addresses.  The election process provides dynamic fail over
   in the forwarding responsibility should the Master become
   unavailable.  This allows any of the virtual router IP addresses on
   the LAN to be used as the default first hop router by end-hosts.  The
   advantage gained from using VRRP is a higher availability default
   path without requiring configuration of dynamic routing or router
   discovery protocols on every end-host.

Table of Contents

   1.  Introduction. . . . . . . . . . . . . . . . . . . . . . . . .   2
       1.1.  Contributors. . . . . . . . . . . . . . . . . . . . . .   3
       1.2.  Scope . . . . . . . . . . . . . . . . . . . . . . . . .   4
       1.3.  Definitions . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Required Features . . . . . . . . . . . . . . . . . . . . . .   5
       2.1.  IP Address Backup . . . . . . . . . . . . . . . . . . .   5
       2.2.  Preferred Path Indication . . . . . . . . . . . . . . .   5
       2.3.  Minimization of Unnecessary Service Disruptions . . . .   5
       2.4.  Efficient Operation over Extended LANs. . . . . . . . .   6
   3.  VRRP Overview . . . . . . . . . . . . . . . . . . . . . . . .   6
   4.  Sample Configurations . . . . . . . . . . . . . . . . . . . .   7

Hinden                      Standards Track                     [Page 1]
RFC 3768                          VRRP                        April 2004

       4.1.  Sample Configuration 1. . . . . . . . . . . . . . . . .   7
       4.2.  Sample Configuration 2. . . . . . . . . . . . . . . . .   9
   5.  Protocol. . . . . . . . . . . . . . . . . . . . . . . . . . .  10
       5.1.  VRRP Packet Format. . . . . . . . . . . . . . . . . . .  10
       5.2.  IP Field Descriptions . . . . . . . . . . . . . . . . .  10
       5.3.  VRRP Field Descriptions . . . . . . . . . . . . . . . .  11
   6.  Protocol State Machine. . . . . . . . . . . . . . . . . . . .  13
       6.1.  Parameters per Virtual Router . . . . . . . . . . . . .  13
       6.2.  Timers. . . . . . . . . . . . . . . . . . . . . . . . .  14
       6.3.  State Transition Diagram. . . . . . . . . . . . . . . .  15
       6.4.  State Descriptions. . . . . . . . . . . . . . . . . . .  15
   7.  Sending and Receiving VRRP Packets. . . . . . . . . . . . . .  18
       7.1.  Receiving VRRP Packets. . . . . . . . . . . . . . . . .  18
       7.2.  Transmitting Packets. . . . . . . . . . . . . . . . . .  19
       7.3.  Virtual MAC Address . . . . . . . . . . . . . . . . . .  19
   8.  Operational Issues. . . . . . . . . . . . . . . . . . . . . .  20
       8.1.  ICMP Redirects. . . . . . . . . . . . . . . . . . . . .  20
       8.2.  Host ARP Requests . . . . . . . . . . . . . . . . . . .  20
       8.3.  Proxy ARP . . . . . . . . . . . . . . . . . . . . . . .  20
       8.4.  Potential Forwarding Loop . . . . . . . . . . . . . . .  21
   9.  Operation over FDDI, Token Ring, and ATM LANE . . . . . . . .  21
       9.1.  Operation over FDDI . . . . . . . . . . . . . . . . . .  21
       9.2.  Operation over Token Ring . . . . . . . . . . . . . . .  21
       9.3.  Operation over ATM LANE . . . . . . . . . . . . . . . .  23
   10. Security Considerations . . . . . . . . . . . . . . . . . . .  23
   11. Acknowledgements. . . . . . . . . . . . . . . . . . . . . . .  24
   12. References. . . . . . . . . . . . . . . . . . . . . . . . . .  24
       12.1. Normative References. . . . . . . . . . . . . . . . . .  24
       12.2. Informative References. . . . . . . . . . . . . . . . .  25
   13. Changes from RFC2338. . . . . . . . . . . . . . . . . . . . .  25
   14. Editor's Address. . . . . . . . . . . . . . . . . . . . . . .  26
   15. Full Copyright Statement. . . . . . . . . . . . . . . . . . .  27
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