[TUHS] Early Internet work (Was: History of select(2))

Noel Chiappa jnc at mercury.lcs.mit.edu
Fri Jan 13 23:19:44 AEST 2017


    > From: Paul Ruizendaal

    >> On 12 Jan 2017, at 4:54 , Clem Cole wrote:

    >> The specifications for what would become IP and TCP were kicking around
    >> ... in the late 1970s.

The whole works actually started considerably earlier than that; the roots go
back to 1972, with the formation of the International Packet Network Working
Group - although that group went defunct before TCP/IP itself was developed
under DARPA's lead.

I don't recall the early history well, in detail - there's a long draft
article by Ronda Hauben which goes into it in detail, and there's also "INWG
and the Conception of the Internet: An Eyewitness Account" by Alexander
McKenzie which covers it too.

By 1977 the DARPA-led effort had produced several working prototype
implementations, and TCP/IP (originally there was only TCP, without a separate
data packet carriage layer) were up to version 3.

    > My understanding is that all RFC's and IEN's were available to all legit
    > users of the Arpanet.

Yes and no. The earliest distribution mechanism (for the initial NCP/ARPANet
work) was hardcopy (you can't distribute things over the 'net before you have
it working :-), and in fact until a recent effort to put them all online, not
all RFC's were available in machine-readable form. (I think some IEN's still
aren't.) So for many of them, if you wanted a copy, you had to have someone at
ISI make a photocopy (although I think they stocked them early on) and
physically mail it to you!

    > Apparently nobody had the idea to put all RFC's in a directory and give
    > FTP access to it.

I honestly don't recall when that happened; it does seem obvious in
retrospect! Most of us were creating document in online text systems, and it
would have been trivial to make them available in machine-readable form. Old
habits die hard, I guess... :-)

    > I think I should put a question out about this, over on the internet
    > history mailing list.

Yes, good idea.


    > As an aside: IMHO, conceptually the difference between NCP and TCP
    > wasn't all that big.

Depends. Yes, the service provided to the _clients_ was very similar (which
can be seen in how similar the NCP and TCP versions of thing like TELNET, FTP,
etc were), but internally, they are very different.

    > In my current understanding the big difference that was NCP assumes
    > in-order, reliable delivery of packets ... and that TCP allows for
    > unreliable links.

Yes, that's pretty accurate (but it does mean that there are _a lot_ of
differences internally - re-transmissions, etc). One other important
difference is that there's no flow control in the underlying network
(something that took years to understand and deal with properly).

    > yes, these concepts were kicking around for over a decade in academia
    > before BSD.

TCP/IP was the product of a large, well-organized, DARPA-funded and -led
effort which involved industry, academic and government players (the first
two, for the most part, DARPA-funded). So I wouldn't really call it an
'academic' project.

	Noel


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