RFC 1831 (rfc1831) - Page 2 of 18
RPC: Remote Procedure Call Protocol Specification Version 2
Alternative Format: Original Text Document
RFC 1831 Remote Procedure Call Protocol Version 2 August 1995
1. INTRODUCTION
This document specifies version two of the message protocol used in
ONC Remote Procedure Call (RPC). The message protocol is specified
with the eXternal Data Representation (XDR) language [9]. This
document assumes that the reader is familiar with XDR. It does not
attempt to justify remote procedure calls systems or describe their
use. The paper by Birrell and Nelson [1] is recommended as an
excellent background for the remote procedure call concept.
2. TERMINOLOGY
This document discusses clients, calls, servers, replies, services,
programs, procedures, and versions. Each remote procedure call has
two sides: an active client side that makes the call to a server,
which sends back a reply. A network service is a collection of one
or more remote programs. A remote program implements one or more
remote procedures; the procedures, their parameters, and results are
documented in the specific program's protocol specification. A
server may support more than one version of a remote program in order
to be compatible with changing protocols.
For example, a network file service may be composed of two programs.
One program may deal with high-level applications such as file system
access control and locking. The other may deal with low-level file
input and output and have procedures like "read" and "write". A
client of the network file service would call the procedures
associated with the two programs of the service on behalf of the
client.
The terms client and server only apply to a particular transaction; a
particular hardware entity (host) or software entity (process or
program) could operate in both roles at different times. For
example, a program that supplies remote execution service could also
be a client of a network file service.
3. THE RPC MODEL
The ONC RPC protocol is based on the remote procedure call model,
which is similar to the local procedure call model. In the local
case, the caller places arguments to a procedure in some well-
specified location (such as a register window). It then transfers
control to the procedure, and eventually regains control. At that
point, the results of the procedure are extracted from the well-
specified location, and the caller continues execution.
Srinivasan Standards Track