[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[ih] ARPANET, operational/experimental

Dave, Vint, anybody else who was there at the very beginning:

Dave Walden wrote:
> At 08:56 PM 8/31/2014, Vint Cerf wrote:
>> The first time I met Bob Kahn and Dave Walden was on the occasion of 
>> their visit to UCLA in late 1969 or early 1970 to conduct a series of 
>> experiments to generate traffic and observe the way in which the IMPs 
>> and their protocols and algorithms responded. Bob Kahn had concerns 
>> that under certain conditions the network would lock up and this 
>> visit was a first opportunity to use the then 4-node network to 
>> stress its capacity.  In the course of a couple of weeks, Bob 
>> designed and I programmed a series of traffic generation and network 
>> measurement experiments that indeed locked the network up multiple 
>> times and in multiple ways. Reassembly lockup and store-and-forward 
>> lockup stand out in my mind in particular.
> Dave W.:
>> In my mind the years of the ARPANET were a big experiment in whether 
>> IMP hardware and sofware and host software and hardware and IMP/host 
>> interfaces and host/host protocols and NWG collaboration could be 
>> developed and made to work reliably enough such that the hosts could 
>> talk to each other, experiments could be run (e.g., at the NMC, 
>> trying packet voice, trying internetworkimg, trying improved routimg, 
>> ...), and various users could try ("experiment") using the net to do 
>> their more or less operational work (e.g., using a TIP to access a 
>> mainframe computer rather than havin one's own, using the net rather 
>> than specially leased lines to move seismic data from Norway to 
>> Alexandria, ...).  And certainly some of our "operational" 
>> improvements seemed like experiments ("now that we have check summed 
>> the routing packets, I wonder if we will see more of those routing 
>> kind of crashes"). 
> In the case of the lock-ups mentioned by Vint, my memory is that Bob 
> and I could make them happen just using the IMPs' internal traffic 
> generators, and then Vint and Bob did a more systematic series of 
> tests. And then much study, a simulation, and a report done back at 
> BBN eventually led to the IMP code changes that were implemented. See
> http://xn--brwolff-5wa.de/bbn-arpanet-reports-collection/BBN%20(1971)%20A%20Study%20of%20the%20Arpa%20Network%20Design%20and%20Performance%20(Report%202161).pdf
> <http://xn--brwolff-5wa.de/bbn-arpanet-reports-collection/BBN%20%281971%29%20A%20Study%20of%20the%20Arpa%20Network%20Design%20and%20Performance%20%28Report%202161%29.pdf>In 
> the meantime while the change was being developed, we asked the hosts 
> to please try to avoid generating traffic of the kind now known to 
> lock up the net, and they did avoid it and the net continued to be 
> used "operationally" for its other work and experiments.
> We all had our roles in this big experiment.  A significant part of 
> the BBN "IMP guys" role was to "keep it running" while continuing to 
> improve it and making changes to facilitate the experiments other 
> groups were doing.  I think the experiment of building the ARPANET and 
> improving it for a number of years was a success.

Since this list is all about "internet history...." - let's take this 
one step further:

What do you recall about the "mindset" of the various people and 
organizations at the time - particularly at the VERY beginning (the RFP 
and proposal):  Did people view this as
- an engineering and operational project, with some experimental 
aspects, or, as Dave puts it,
- as a "big experiment" first, framed as an engineering/operational 


In theory, there is no difference between theory and practice.
In practice, there is.   .... Yogi Berra