[ih] UDP creation (Was: Date of RFC 791 for celebration)

Noel Chiappa jnc at mercury.lcs.mit.edu
Tue Apr 4 17:38:55 PDT 2006

    > From: "David P. Reed" <dpreed at reed.com>

    >> David, I wonder, are you conflating two different meetings in your
    >> memory?
    >> ...
    >> the UDP spec didn't come out until January 1979 (IEN-71, Reed,
    >> 21-Jan-79, "User Datagram Protocol") - over a year later.
    >> Also, I do seem to recall the final format for UDP being hashed out at
    >> a meeting I was at, shortly before you published the spec.
    >> Is it possible that the *basic concept* of UDP was worked out at one
    >> meeting (at the time of the [TCP/IP] split), and the final *details*
    >> of the protocol were hashed out at a much later meeting (shortly
    >> before the spec was published)?

    > I didn't conflate the meetings - in fact, I believe the '77 meeting is
    > the one I was describing from memory. There was a basic agreement on a
    > UDP at the first meeting. Since no one was implementing UDP, there was
    > no need for a spec at that point. 
    > ...
    > I recall the spec of UDP (which is barely worthy of the name, it's so
    > simple in concept) being written as part of a cleanup process, pushed
    > by Postel to close some loose ends. Remember the point of UDP was to
    > support such things as packet speech, message exchange protocols like
    > DNS, ... and we were still far from understanding what might need to be
    > in UDP for such things. So a long delay from conception to spec'ing was
    > actually what happened.

I don't see that our views necessarily conflict - as I said, I felt it was
likely only the last details that were worked out that the later meeting.

{Added later...]

In just now looking through the IEN's which were just posted, I found the
following in IEN 63 ("Internet Meeting Notes - 30-31 October 1978" - at SRI,
apparently), on page 12 (comments from me in '[]'}:

  DATAGRAM PROTOCOL - Danny Cohen [discussion lead - JNC]

  There was discussion of the need for a Datagram protocol on top of IN
  [the contemporaneous name for IN - JNC] to multiplex IN datagrams to
  various datagram application processes, such as the name server process.

  Dave Reed suggested the following and was then asked to prepare a memo
  on it:

  [Picture of UDP header - JNC]

So it seems my memory of discussion of "the final format for UDP" at a
meeting shortly before the publication of UDP spec (in January, '79) was
correct, although my memory of where that meeting was was wrong (I had
thought it was at ISI).

[Parenthetical note about memory: I'm not a trained historian, but I've done
a certain amount of amateur work, and I gather that historians are wary of
memories, because they do play tricks. I have had several prior experiences
with this, including a rather amusing one in the field of Lotus Indianapolis
race-car history (something I specialized in), which is written up here:


I have come to believe that it's dangerous to rely on memories unaided by any
contemporaneous records, because human memory is so fallible - and when it
"drops a bit", there's often no clue.]


More information about the internet-history mailing list