Proposed experiment with a Message Switching Protocol
RFC 333
|
Document |
Type |
|
RFC - Unknown
(May 1972; No errata)
|
|
Authors |
|
|
|
Last updated |
|
2013-03-02
|
|
Stream |
|
Legacy stream
|
|
Formats |
|
plain text
html
pdf
htmlized (tools)
htmlized
bibtex
|
Stream |
Legacy state
|
|
(None)
|
|
Consensus Boilerplate |
|
Unknown
|
|
RFC Editor Note |
|
(None)
|
IESG |
IESG state |
|
RFC 333 (Unknown)
|
|
Telechat date |
|
|
|
Responsible AD |
|
(None)
|
|
Send notices to |
|
(None)
|
Network Working Group Bob Bressler
Request for Comments: 333 MIT/Dynamic Modeling
NIC # 9926 Dan Murphy
Category: C9 (experimentation) BBN/TENEX
Obsoletes: 62 Dave Walden
Updates: none BBN/IMP
15 May 1972
A PROPOSED EXPERIMENT WITH A MESSAGE SWITCHING PROTOCOL
CONTENTS
Introduction .................................................. 1
Some Background ............................................... 2
References .................................................... 3
MSP Specification ............................................. 4
Issue ......................................................... 8
Message Header ................................................ 10
Examples ...................................................... 15
TELNET ........................................................ 16
The Information Operator ...................................... 16
Unique Port Numbers ........................................... 20
Flow Chart .................................................... 23
MSP Variations ................................................ 25
Appendix ...................................................... 26
INTRODUCTION
A message switching protocol (MSP) is a system whose function is to
switch messages among its ports.
For example, there is an implementation of an MSP in each Interface
Message Processor. We believe that the effective utilization of
communications networks by computer operating systems will require a
better understanding of MSPs. In particular, we feel that Network
Control Programs (NCPs), as they have been implemented on the ARPA
Computer Network (ARPANET), do not adequately emphasize the
communications aspects of networking -- i.e., they reflect a certain
reluctance on the part of systems people to move away from what we
term "the stream orientation". We propose, as an aside the network
development using the current NCPs, to rethink the design of NCP-
level software beginning with a consideration of MSPs.
The thrust of this note is to sketch how one would organize the
lowest level host-host protocol in the ARPANET around MSPs and how
this organization would affect the implementation of host software.
Bressler, et al. Experimentation [Page 1]
RFC 333 MESSAGE SWITCHING PROTOCOL EXPERIMENT May 1972
SOME BACKGROUND
Over the past several weeks there has been considerable informal
discussion about the possibility of implementing, on an experimental
basis, in several of the ARPA Network Host Computers, NCPs which
follow a protocol based on the concept of message switching rather
than the concept of line switching (see the parenthetical sentence in
the first paragraph of page 6 of NIC document 8246, Host/Host
Protocol for the ARPA Network). Party to this discussion have been
Bob Bressler (MIT/Dynamic Modeling) Steve Crocker (ARPA), Will
Crowther (BBN/IMP), Tom Knight (MIT/AI), Alex McKenzie (BBN/IMP), Bob
Metcalfe (MIT/Dynamic Modeling), Dan Murphy (BBN/TENEX), Jon Postel
(UCLA/NMC), and Dave Walden (BBN/IMP).
Several interesting points and conclusions have been made during this
discussion:
1. Bressler has implemented a message switched interprocess
communication system for the Dynamic Modeling PDP-10 and has
extended it so it could be used for interprocess communication
between processes in the Dynamic Modeling PDP-10 and the AI
PDP-10. He reports that it is something like an order of
magnitude smaller than his NCP.
2. Murphy has noted that a Host/Host protocol based on message
switching could be implemented experimentally and run in
parallel with the real Host/Host protocol using some of the
links set aside for experimentation. Further, Murphy has noted
that if this experimental message switching protocol were
implemented in TENEX, a number of (TENEX) sites could easily
participate in the experiment.
3. It is the consensus of the discussants that Bressler should
take a crack at specifying a message switching protocol* and
that if this specification looked relatively easy to implement,
a serious attempt should be made by Murphy and Bressler to find
the resources to implement the experimental protocol on the two
BBN TENEX and the MIT Dynamic Modeling and AI machines.
4. MSP was chosen as the acronym for Message Switching Protocol,
and links 192-195 were reserved for use in an MSP experiment.
-------------
Show full document text