[ih] Separation of TCP and IP

[Noel Chiappa]

I'm interested in finding out more about the process by which TCP and IP were
separated: to begin with, how it came to be recognized that this separation
was a good thing. (This split was what enabled the later creation of UDP, of
course.) In particular, that the basic service model (of what later became
the internet layer) should be directly usable by applications, and that the
complete data network be accessible not _just_ only via TCP. I am also
interested in who drove this change (if any players in particular stand out).

I have poked around a bit in the early IEN's, but I didn't find much on this
specific area - either why, or who. From comments in IEN-22 "Internet Meeting
Notes - 1 February 1978" (in "Introduction and Objectives) it sounds like the
formal decision to do the split was made at the TCP meeting the day before.
The minutes from that meeting, IEN-67 "TCP Meeting Notes - 30 & 31 January
1978", don't provide much, though. IEN-66 "TCP Meeting Notes - 13 & 14
October 1977" shows that there had been a drift in this direction for a
while; it didn't seem to be present as of IEN-3, "Internet Meeting Notes - 15
August 1977", though.

I arrived on the scene shortly after this happened (my first meeting was the
August 1978 one), but I retain some impressions (gained no doubt from
discussions with people like Clark and Reed). These are the impressions that
I retain: that Danny was _a_ significant force in making this happen, because
of his voice work - for which timeliness was important, not correctness. (In
IEN-67, "Arrangements - Cohen" Danny "complain[ed] about TCP-3 becoming all
things to all people".) Is that correct? (If so, it's probably his most
significant technical legacy.) For others, I think Dave Reed may have been in
favour too (perhaps he'd already started to think of RPC-like things). And
perhaps some of the other voice people - e.g. Forgie? And I'm sure the PARC
guys were trying to throw a few clues our way. Am I missing anyone? Did
anyone stand out as being a bigger influence than the rest?

Maybe there's some significan paper that discusses the architectural benefit
of making the basic unreliable data carriage substrate accessible to _some_
applications, but the concept didn't seem to get much coverage in the IENs.
Maybe it was so obviously the Right Thing that not much discussion was
needed, and the only question was when/how to do it?

	Noel