RFC 903 (rfc903) - Page 1 of 4

Reverse Address Resolution Protocol

Alternative Format: Original Text Document
Next >
Network Working Group                    Finlayson, Mann, Mogul, Theimer
Request for Comments: 903                            Stanford University
                                                               June 1984

                 A Reverse Address Resolution Protocol


      Ross Finlayson, Timothy Mann, Jeffrey Mogul, Marvin Theimer
                      Computer Science Department
                          Stanford University
                               June 1984

Status of this Memo

   This RFC suggests a method for workstations to dynamically find their
   protocol address (e.g., their Internet Address), when they know only
   their hardware address (e.g., their attached physical network
   address).

   This RFC specifies a proposed protocol for the ARPA Internet
   community, and requests discussion and suggestions for improvements.

I. Introduction

   Network hosts such as diskless workstations frequently do not know
   their protocol addresses when booted; they often know only their
   hardware interface addresses.  To communicate using higher-level
   protocols like IP, they must discover their protocol address from
   some external source.  Our problem is that there is no standard
   mechanism for doing so.

   Plummer's "Address Resolution Protocol" (ARP) [1] is designed to
   solve a complementary problem, resolving a host's hardware address
   given its protocol address.  This RFC proposes a "Reverse Address
   Resolution Protocol" (RARP).  As with ARP, we assume a broadcast
   medium, such as Ethernet.

II. Design Considerations

   The following considerations guided our design of the RARP protocol.

   A. ARP and RARP are different operations.  ARP assumes that every
   host knows the mapping between its own hardware address and protocol
   address(es).  Information gathered about other hosts is accumulated
   in a small cache.  All hosts are equal in status; there is no
   distinction between clients and servers.

   On the other hand, RARP requires one or more server hosts to maintain
   a database of mappings from hardware address to protocol address and
   respond to requests from client hosts.



Finlayson, Mann, Mogul, Theimer
Next >