[ih] NIC, InterNIC, and Modelling Administration

[John Day]

>Of course, IMP-IMP and IMP-Host are at the /same/ layer, upon which
>there is sender-IMP-to-receiver-IMP (with the error correction and flow
>control at that level), and then there is Host-Host, and then all the

The proper terminology here is that they were different layers of the 
same rank.

I don't think there was much confusion if any about interfaces and 
protocols in the ARPANET or the research networks in general. 
Interfaces were within a system, i.e. APIs and protocols were between 
systems.

This was all "in the air" from Dykstra's THE and the common practive 
even then of building software as blackboxes.  This use of interface 
as between software modules within a system was quite common in 
computing.  Although not in telelcom.  But then we weren't doing 
telecom.

There was confusion once we encountered the CCITT who considered 
interfaces as being between boxes.  Especially between boxes owned by 
different entities.  But that was the old beads-on-a-string model 
that was being replaced.  To them interface and protocol were the 
same thing.

>app level stuff. This take on layering has been well put in Dave Clark's
>1974 PhD thesis, but can also be infered fairly straightforwardly from
>the BBN reports at the time, particularly the evolution of the ever more
>distant host stuff that was added virtually right away in the very early
>1970s.
>
>Matthias
>
>P.S. The above list is by absolutely no means to be taken as exhaustive,
>especially in the INWG line of documents there are bound to be useful
>elaborations of the layering notion, e.g. by Pouzin who in 1973 was very
>adamant about clean and inviolable separation of layers already.
>
>Am Freitag, den 18.02.2011, 11:32 -0500 schrieb Vint Cerf:
>>  i think there was a much earlier layering paper, lead author postel,
>>  1972? Spring Joint or Fall Joint Computer Conference.
>>
>>
>>  v
>>
>>
>>  On Fri, Feb 18, 2011 at 11:02 AM, Craig Partridge
>>  <craig at aland.bbn.com> wrote:
>>          >
>>          >
>>          > On 2/18/2011 6:45 AM, Craig Partridge wrote:
>>          > > If you read the original OS layering paper by Hubert
>>          Zimmerman it is
>>          > > clearly a top-down management work plan.  Useful to
>>          compare it with
>>          > > the ARPANET layering paper of a few years later.  The
>>          difference is Zim's
>>          > > "here's how we'll break up the problem of developing
>>          standards" vs.
>>          > > "here's why creating TELNET led us to a layered
>>          architecture".
>>          >
>>          >
>>          > As I recall, documentation of the Arpanet approach to
>>          layering occurred as a
>>          > response to the OSI papers.  Prior to that it was de facto
>>          but not documented
>>        
>>        
>>          That was the received wisdom I got in 1983.  But when I went
>>          digging in
>>          1987 or so, I discovered it wasn't true.
>>        
>>          The ARPANET layering paper was published by Davidson et al at
>>          the 5th
>>          IEEE Data Comm Conference in 1977.  Zim's paper appeared in
>>          1980.
>>        
>>          Thanks!
>>        
>>          Craig
>>
>>