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diff --git a/doc/rfc/rfc37.txt b/doc/rfc/rfc37.txt new file mode 100644 index 0000000..2d5cd95 --- /dev/null +++ b/doc/rfc/rfc37.txt @@ -0,0 +1,271 @@ + + + + + + +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. + + + + + + + + [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. + + + + + + + + + + + + + [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 ] + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + [Page 5] + |