[ih] early networking

[Leonard Kleinrock]

Steve,

Right on re Wes and the IMP idea.  It is notable that Wes (and Charles Molnar) created the LINC minicomputer in 1961/1962 and this probably influenced Wes in championing the idea of offloading functionality to small special purpose computers.  Side note: Wes was my supervisor at Lincoln Lab when I was a grad student at MIT and was an amazing leader and innovator.
Len


> On Apr 30, 2024, at 2:07 PM, Steve Crocker via Internet-history <internet-history at elists.isoc.org> wrote:
> 
> John,
> 
> My understanding re the idea for the IMPs is slightly different.  Yes,
> there was pushback from some of the sites, but I have understood the
> introduction of the IMP idea came from Wes Clark.  (See
> https://en.wikipedia.org/wiki/Wesley_A._Clark)  He was deeply involved with
> small computers.  The introduction of  the IMPs into the design provided a
> clean separation between the subnet and the hosts.  The reliability of
> the overall system was dependent only on the IMPs and the lines.  In those
> days, it was fairly rare for an operating system to have 24 hours of
> continuous operation.
> 
> Re the protocol, the few of us who were involved at the outset of the host
> level protocol design focused on connections as the basic building block.
> I'll take the blame for this narrow focus if we need someone to blame.  (On
> the other hand, if it's a matter of giving credit, there were several of
> us.)  Walden's IPC concept came along after we were far down the path of
> designing the host-host protocol.  That said, general interprocess
> communication was part of our thinking from the start.
> 
> John White from UCSB also pushed for remote procedure calls as a basic
> building block.  It was a powerful idea but didn't dissuade us from
> choosing a virtual bitstream as the building block.  Maybe it should have.
> 
> Along a separate path, Danny Cohen was interested in real-time
> applications, particularly voice and flight simulation.  His work, among
> others, led to using messages that were not subject to flow control.
> 
> In all cases, the notion of layers was fundamental and an intrinsic part of
> everyone's thinking coming out of the August 1968 meeting.
> 
> Steve
> 
> 
> On Mon, Apr 29, 2024 at 3:58 PM John Day via Internet-history <
> internet-history at elists.isoc.org> wrote:
> 
>> 
>> As we all know, the ARPANET was the first major packet switching network.
>> It was built to be a production network to lower the cost of computing for
>> ARPA Projects.  Cyclades was built to be a network to do research on
>> networks. Cyclades was a platform, what today would be called a clean-slate
>> approach having seen the ARPANET. (There was considerable interaction
>> between BBN and CYCLADES: As Dave Walden (who led IMP team) told me, so
>> ’they wouldn’t make the same mistakes we did.’ ;-) And Jean-Louis Grangé
>> (led the CIGALE team) spent a fair amount of time at BBN.)
>> 
>> Because Roberts had gotten considerable resistance from the potential host
>> sites when he proposed just a network of hosts, the IMPs were proposed to
>> ‘off-load’ the network from the hosts. Hence for the ARPANET, the host used
>> the IMP-Host protocol to allocate a ‘connection’ to the destination and
>> then the Host-Host Protocol created a connection between processes in the
>> two machines. The applications were built on top of it. (Note NCP did flow
>> control but no retransmissions because the IMP subnet was reliable.) This
>> is when layers were first introduced. (Again, Walden confirmed for me that
>> there were no layer diagrams of the IMP subnet and I wouldn’t have expected
>> them then.) This is when the idea that networking was IPC began. Walden
>> wrote a very early RFC proposing IPC for a resource sharing network.)
>> 
>> sender
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