Subject: Re: [Hist Trivia] IP Protocol Layers

From: Radia Perlman - Boston Center for Networking <[email-masked]>
Date: Tue, 17 Jul 2001 17:19:41 -0400 (EDT)

I think TCP and IP were all one layer at one point. It's possible
the old IEN's, (which I'd heard would be on-line "soon" if
they're not already), would have
a spec for the combined TCP/IP, and it would probably use the terminology in
use at the time.

By the way, when I started at Digital to be the "Transport architect",
DECnet's layers were layer3=Transport, and layer4=Network Services.
Frankly I think Transport is a much better name for layer 3 than layer 4.
Layer 4 happens just at the endnode. It's layer 3 that actually
"transports" the data. Since I saw everyone getting confused when
they'd be talking about "Network layer" or "transport layer", which
was opposite in DECnet and OSI, I lobbied for changing the DECnet terms
(since we didn't have the clout to change the OSI terminology). Instead
of immediately swapping the names, we went through a few years of
neutral terms..."routing layer" for layer 3, and "end-to-end layer" for
layer 4. 

One of the things I've been meaning to chase down is ... why did anyone
think "Transport" was a good name for layer 4? What does the word "transport" 
mean that has anything to do with what layer 4 does?

Radia

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From: Dave Crocker <[email-masked]>
Date: Tue, 17 Jul 2001 15:33:19 -0700

>the old IEN's, (which I'd heard would be on-line "soon" if

That is my understanding, too:  In the beginning there was only TCP.

During on-going discussions between the ARPA research and the Xerox PARC 
research folks, the need for separating out IP functionality became apparent.

I don't know the dates for this architectural transition.

d/

ps.  FWIW:

>         Application
>         Transport (TCP, UDP)
>         Internet (IP, etc.)
>         Network Interface (LAN and WAN technologies).

         The idea of intermediate "upper" layers has periodically been 
played with in the Internet realm, such as with XDR and RPC, and again more 
recently with BEEP. A range of efforts that standardize on an application 
infrastructure, such as with XML, encourage viewing this as a real 
architectural enhancement. Hence we probably need to wedge a layer between 
transport and applications.  I prefer to call it session; others will 
likely prefer presentation.

----------
Dave Crocker  <mailto:[email-masked]>
Brandenburg InternetWorking  <http://www.brandenburg.com>
tel +1.408.246.8253;  fax +1.408.273.6464

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From: "Jim Fleming" <[email-masked]>
Date: Tue, 17 Jul 2001 18:24:09 -0500

RFC-2001-06-24-000 - 2001 A Space Odyssey
http://www1.ietf.org/mail-archive/ietf/Current/msg12458.html

http://www.networksorcery.com/enp/rfc/rfc25.txt
"Because it may be desirable to reserve one or more link numbers for
instrumentation purposes, and because 256 link numbers are many more
than are needed, we suggest that no link number over 63 be used.  At
UCLA, we will implement our tables to take advantage of this limitation.
We also note that 32 may be even more realistic, but 64 is certainly
sufficient."
-------------

http://www1.ietf.org/mail-archive/ietf/Current/msg12524.html
RFC-2001-06-27-001 - Obtaining IPv8 Address Allocations

The "toy" IPv4 Internet is a sewer.
IPv8 is designed to be a swamp to cover the sewer.
IPv16 is the "high-ground"....

...here are some links...

Jim Fleming
http://www.unir.com
Mars 128n 128e
http://www.unir.com/images/architech.gif
http://www.unir.com/images/address.gif
http://www.unir.com/images/headers.gif
http://www.ntia.doc.gov/ntiahome/domainname/130dftmail/unir.txt
http://msdn.microsoft.com/downloads/sdks/platform/tpipv6/start.asp
http://www.ietf.org/mail-archive/ietf/Current/msg12213.html
http://www.ietf.org/mail-archive/ietf/Current/msg12223.html

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From: vint cerf <[email-masked]>
Date: Wed, 18 Jul 2001 10:26:56 -0400

>a spec for the combined TCP/IP, and it would probably use the terminology in

we started with only TCP - that was in the 1974 article. by 1978 we split
into two layers so that we could service requirements for low delay but
not necessarily high reliability (e.g. voice). Danny Cohen, Dave Clark and
Jon Postel all had a hand in arguing for the split - 

>mean that has anything to do with what layer 4 does?

possibly "door to door" service??