RFC 753 (rfc753) - Page 2 of 57
Internet Message Protocol
Alternative Format: Original Text Document
Postel
March 1979
Internet Message Protocol
TABLE OF CONTENTS
PREFACE ........................................................ iii
1. INTRODUCTION ..................................................... 1
1.1. Motivation ................................................... 1
1.2. Scope ........................................................ 1
1.3. The Internetwork Environment ................................. 2
1.4. Operation .................................................... 2
1.5. Interfaces ................................................... 3
2. FUNCTIONAL DESCRIPTION ........................................... 5
2.1. Relation to Other Protocols .................................. 5
2.2. Terminology ................................................. 5
2.3. Assumptions .................................................. 6
2.4. General Specification ........................................ 7
2.5. Mechanisms .................................................. 11
3. DETAILED SPECIFICATION .......................................... 13
3.1. Overview of Message Structure ............................... 13
3.2. Data Elements ............................................... 13
3.3. Message Objects ............................................. 16
3.4. Command ..................................................... 23
3.5. Document .................................................... 31
3.6. Message Structure ........................................... 33
3.7. MPM Organization ............................................ 36
3.8. Interfaces .................................................. 39
4. EXAMPLES & SCENARIOS ............................................ 41
Example 1: Message Format ........................................ 41
Example 2: Delivery and Acknowledgment ........................... 43
GLOSSARY ............................................................ 49
REFERENCES .......................................................... 51
APPENDICES .......................................................... 53
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Internet Message Protocol
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Internet Message Protocol
PREFACE
This is the first edition of this specification and should be treated as
a request for comments, advice, and suggestions. A great deal of prior
work has been done on computer aided message systems and some of this is
listed in the reference section. This specification was shaped by many
discusions with members of the ARPA research community, and others
interested in the development of computer aided message systems. This
document was prepared as part of the ARPA sponsored Internetwork
Concepts Research Project at ISI, with the assistance of Greg Finn, Alan
Katz, Paul Mockapetris, and Mamie Chew.
Jon Postel
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Internet Message Protocol
[Page iv] Postel
March 1979
IEN: 85 J. Postel
RFC: 753 USC-ISI
March 1979
INTERNET MESSAGE PROTOCOL
1. INTRODUCTION
This document describes an internetwork message system. The system is
designed to transmit messages between message processing modules
according to formats and procedures specified in this document. The
message processing modules are processes in host computers. Message
processing modules are located in different networks and together
constitute an internetwork message delivery system.
This document is intended to provide all the information necessary to
implement a compatible cooperating module of this internetwork message
system.
1.1. Motivation
As computer supported message processing activities grow on individual
host computers and in networks of computers, there is a natural desire
to provide for the interconnection and interworking of such systems.
This specification describes the formats and procedures of a general
purpose internetwork message system, which can be used as a standard
for the interconnection of individual message systems, or as a message
system in its own right.
We also provide for the communication of data items beyond the scope
of contemporary message systems. Messages can include typed segments
which could represent drawings, or facsimile images, or digitized
speech. One can imagine message stations equipped with speakers and
microphones (or telephone hand sets) where the body of a message or a
portion of it is recorded digitized speech. The output terminal could
include a graphics display, and the message might present a drawing on
the display, and verbally (via the speaker) describe certain features
of the drawing. This specification provides basic data elements for
the transmission of structured binary data, as well as providing for
text transmission.
1.2. Scope
The Internet Message Protocol is intended to be used for the
transmission of messages between networks. It may also be used for
the local message system of a network or host. This specification was
developed in the context of the ARPA work on the interconnection of
networks, but it is anticipated that it has a more general scope.
Postel
