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+Network Working Group S. Crocker
+Request for Comments: 37 UCLA
+ 20 March 1970
+
+ Network Meeting Epilogue, etc.
+
+The Meeting
+-----------
+
+ On Tuesday, March 17, 1970, I hosted a Network meeting at UCLA.
+ About 25 people attended, including representatives from MIT, LL,
+ BBN, Harvard, SRI, Utah, UCSB, SDC, RAND and UCLA. I presented a
+ modification of the protocol in NWG/RFC #33; the modifications are
+ sketchily documented in NWG/RFC #36. The main modification is the
+ facility for dynamic reconnection.
+
+ The protocol based on sockets and undistinguished simplex
+ connections is quite different from the previous protocol as
+ documented in NWG/RFC #11. The impetus for making such changes came
+ out of the network meeting on December 8, 1969, at Utah, at which
+ time the limitations of a log-in requirement and the inability to
+ connect arbitrary processes was seriously challenged. Accordingly,
+ the primary reason for the recent meeting was to sample opinion on
+ the new protocol.
+
+ Recollections may vary, but it is my opinion that the protocol was
+ widely accepted and that the criticism and discussion fell into two
+ categories:
+
+ 1. Questioning the complexity and usefulness of the full protocol,
+ especially the need for dynamic reconnection.
+
+ 2. Other topics, particularly character set translation, higher
+ level languages, incompatible equipment, etc.
+
+ Notably lacking was any criticism of the basic concepts of sockets
+ and connections. (Some have since surfaced.) The following
+ agreements were made:
+
+ 1. By April 30, I would be responsible for publishing an
+ implementable specification along lines presented.
+
+ 2. Any interested party would communicate with me (at least)
+ immediately if he wished to modify the protocol.
+
+
+
+
+
+
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+ [Page 1]
+
+RFC 37 Network Meeting Epilogue, etc. 20 March 1970
+
+ 3. If major modifications come under consideration, interested
+ parties would meet again. This would happen in two to three
+ weeks.
+
+ 4. Jim Forgie of Lincoln Labs tentatively agreed to host a meeting
+ on higher level network languages, probably near Spring Joint
+ time.
+
+Mailing List Changes
+--------------------
+
+ Paul Rovner of LL is replaced by
+
+ James Forgie
+ Mass. Institute of Technology
+ Lincoln Laboratory C158
+ P.O. Box 73
+ Lexington, Mass. 02173
+
+ telephone at (617) 862-5500 ext. 7173
+
+ Professor George MEaly is added
+
+ George Mealy
+ Rm. 220
+ Aitken Computation Lab.
+ Harvard University
+ Cambridge, Massachusetts 02138
+
+ telephone at (617) 868-1020 ext. 4355
+
+Process
+-------
+
+ In all of our writing we have used the term process, to mean a
+ program which has an assigned location counter and an address space.
+ A program is merely a pattern of bits stored in some file. A new
+ process is created only by an already existing process. The
+ previous process must execute an atomic operation (forc, attach,
+ etc.) to cause such a creation. Processes may either cause their
+ own demise or be terminated by another (usually superior) process.
+
+ The above definition corresponds to the definition given by
+ Vyssotsky, et al on pp. 206, 207 of "Structure of the Multics
+ Supervisor" in the FJCC proceedings, 1965.
+
+
+
+
+ [Page 2]
+
+RFC 37 Network Meeting Epilogue, etc. 20 March 1970
+
+ Because a process may create another process, and because in general
+ the two processes are indistinguishable when viewed externally, I
+ know of no reasonable way for two processes to request connection
+ directly with each other. The function of sockets is to provide a
+ standard interface between processes.
+
+The Days After
+--------------
+
+ In the time since the meeting I have had conversations with Steve
+ Wolfe (UCLA-CCN), Bill Crowther (BBN), and John Heafner and Erick
+ Harslem (RAND). Wolf's comments will appear as NWG/RFC #38 and fall
+ into a class I will comment on below.
+
+ Crowther submitted the following:
+
+ "A brief description of two ideas for simplifying the host protocol
+ described at the March meeting. These ideas have not been carefully
+ worked out.
+
+ Idea 1. To Reconnect.
+ --------------------
+
+ "A NCP wanting to Reconnect tells each of his neighbors "I want to
+ reconnect". They wait until there are no messages in transit and
+ respond "OK". He then says "Reconnect as follows" and they do it.
+ In the Rare condition, the NCP gets back an "I want to reconnect
+ instead of an "OK", then one must go and one must stop. So treat a
+ "reconnect" from a higher Host user etc. as an ok and from a lower
+ as a "No-wait until I reconnect you" and do the connection.
+
+ Idea 2
+ ------
+
+ "Decouple connections and links. Still establish connections, but
+ use any handy link for the messages. Don't send another message on
+ a connection until a FRNM comes back. Include source and
+ destination socket numbers in the packet.
+
+ "To reconnect, say to each of neighbors "please reconnect me as
+ follows...". Hold onto the connect for a short time (seconds) and
+ send both packets and connection messages along toward their
+ destinations. I haven't worked out how to keep the in-transit
+ messages in order, but probably everything works if you don't send
+ out a reconnect when RFNM's are pending."
+
+
+
+
+ [Page 3]
+
+RFC 37 Network Meeting Epilogue, etc. 20 March 1970
+
+ Bill's first idea does not seem to me to be either decisively better
+ or (after some thought) very different, and I am considering it. I
+ have no strong feelings about it yet, but I am trying to develop
+ some.
+
+ Bill's second idea seems contrary to my conception of the role of
+ links. An argument in favor of decoupling connections and links
+ that the number of connections between two hosts might want to
+ exceed 255, and that even if not, it is sounder practice to isolate
+ dependancies in design. On the other hand, the newly provided Cease
+ on Link facility* (page 22 of the soon to be released BBN report
+ #1822 revised Febuary 1970) becomes useless. (Bill, who just put
+ the feature in, doesn't care.) Another objection is that it seems
+ intuitively bad to waste the possibility of using the link field to
+ carry information. (Note the conflict of gut level feelings).
+
+ In a conversation with John Haefner and Eric Harslem of RAND, the
+ pointed out that the current protocol makes no provision for error
+ detection and reporting, status testing and reporting, and expansion
+ and experimentation. Error detection and status testing will
+ require some extended discussion to see what is useful, and I expect
+ that such discussion will take place while implementation proceeds.
+ Leaving room for protocol expansion and experimentation, however, is
+ best done now.
+
+ I suggest that two areas for expansion be reserved. One is that
+ only a fraction of the 256 links be used, say the first 32. The
+ other area is to use command codes from 255 downward, with permanent
+ codes assigned from the number of links in use to 32, I feel that it
+ is quite unlikely that we would need more than 32 for quite some
+ time, and moreover, the network probably wouldn't handle traffic
+ implied by heavy link assignment. (These two things aren't
+ necessarily strongly coupled: one can have many links assigned but
+ only a few carrying traffic at any given time.)
+
+ Some of Heafner's and Harslen's other ideas may appear in NWG/RFC
+ form.
+
+
+
+
+
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+
+ [Page 4]
+
+RFC 37 Network Meeting Epilogue, etc. 20 March 1970
+
+ Immediate Interaction
+ ---------------------
+
+ During the next several days, I will still be interested in those
+ editicisms of current protocol which might lead to rejection or
+ serious modification of it. Thereafter, the focus will be a
+ refinement, implementation, extension, and utilization. I may be
+ reached at UCLA through my secretary Mrs. Benita Kristel at (213)
+ 825-2368. Also, everyone is invited to contribuet to the NWG/RFC
+ series. Unique numbers are assigned by Benita.
+
+ * The Cease on Link facility is a way a receiving host modifies
+ RFNM's so as to carry a flow-quenching meaning. An alternative
+ proceedure is to use a host-to-host control command.
+
+ [ This RFC was put into machine readable form for entry ]
+ [ into the online RFC archives by Ron Fitzherbert 1/97 ]
+
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+ [Page 5]
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