RFC 2338 (rfc2338) - Page 2 of 27
Virtual Router Redundancy Protocol
Alternative Format: Original Text Document
RFC 2338 VRRP April 1998
Table of Contents
1. Introduction...............................................2
2. Required Features..........................................5
3. VRRP Overview..............................................6
4. Sample Configurations......................................8
5. Protocol...................................................9
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............................................13
6.2 Timers................................................15
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
9. Operation over FDDI and Token Ring........................21
9.1 Operation over FDDI...................................21
9.2 Operation over Token Ring.............................21
10. Security Considerations...................................23
10.1 No Authentication....................................23
10.2 Simple Text Password.................................23
10.3 IP Authentication Header.............................24
11. Acknowledgments...........................................24
12. References................................................24
13. Authors' Addresses........................................25
14. Full Copyright Statement..................................27
1. Introduction
There are a number of methods that an end-host can use to determine
its first hop router towards a particular IP destination. These
include running (or snooping) a dynamic routing protocol such as
Routing Information Protocol [RIP] or OSPF version 2 [OSPF], running
an ICMP router discovery client [DISC] or using a statically
configured default route.
Running a dynamic routing protocol on every end-host may be
infeasible for a number of reasons, including administrative
overhead, processing overhead, security issues, or lack of a protocol
implementation for some platforms. Neighbor or router discovery
Knight, et. al. Standards Track