[ih] Better-than-Best Effort

[Alex McKenzie]

 This is the second email from Jack mentioning a point-to-point line between the ARPA TIP and the ISI site.  I don't believe that is an accurate statement of the ARPAnet topology.  In January 1975 there were 5 hops between the 2 on the shortest path. In October 1975 there were 6.  I don't believe it was ever one or two hops, but perhaps someone can find a network map that proves me wrong.
Alex McKenzie

    On Saturday, August 28, 2021, 05:06:54 PM EDT, Jack Haverty via Internet-history <internet-history at elists.isoc.org> wrote:  
 
 Sounds right.   My experience was well after that early experimental 
period.  The ARPANET was much bigger (1980ish) and the topology had 
evolved over the years.  There was a direct 56K line (IIRC between 
ARPA-TIP and ISI) at that time.  Lots of other circuits too, but in 
normal conditions ARPA<->ISI traffic flowed directly over that long-haul 
circuit.   /Jack

On 8/28/21 1:55 PM, Vint Cerf wrote:
> Jack, the 4 node configuration had two paths between UCLA and SRI and 
> a two hop path to University of Utah.
> We did a variety of tests to force alternate routing (by congesting 
> the first path).
> I used traffic generators in the IMPs and in the UCLA Sigma-7 to get 
> this effect. Of course, we also crashed the Arpanet with these early 
> experiments.
>
> v
>
>
> On Sat, Aug 28, 2021 at 4:15 PM Jack Haverty <jack at 3kitty.org 
> <mailto:jack at 3kitty.org>> wrote:
>
>    Thanks, Steve.  I hadn't heard the details of why ISI was
>    selected.   I can believe that economics was probably a factor but
>    the people and organizational issues could have been the dominant
>    factors.
>
>    IMHO, the "internet community" seems to often ignore non-technical
>    influences on historical events, preferring to view everything in
>    terms of RFCs, protocols, and such.  I think the other influences
>    are an important part of the story - hence my "economic lens".  
>    You just described a view through a manager's lens.
>
>    /Jack
>
>    PS - I always thought that the "ARPANET demo" aspect of that
>    ARPANET timeframe was suspect, especially after I noticed that the
>    ARPANET had been configured with a leased circuit directly between
>    the nearby IMPs to ISI and ARPA.   So as a demo of "packet
>    switching", there wasn't much actual switching involved.   The 2
>    IMPs were more like multiplexors.
>
>    I never heard whether that configuration was mandated by ARPA, or
>    BBN decided to put a line in as a way to keep the customer happy,
>    or if it just happened naturally as a result of the ongoing
>    measurement of traffic flows and reconfiguration of the topology
>    to adapt as needed.  Or something else.   The interactivity of the
>    service between a terminal at ARPA and a PDP-10 at ISI was
>    noticeably better than other users (e.g., me) experienced.
>
>    On 8/28/21 11:51 AM, Steve Crocker wrote:
>>    Jack,
>>
>>    You wrote:
>>
>>        I recall many visits to ARPA on Wilson Blvd in Arlington, VA.
>>        There were
>>        terminals all over the building, pretty much all connected
>>        through the
>>        ARPANET to a PDP-10 3000 miles away at USC in Marine Del Rey,
>>        CA.  The
>>        technology of Packet Switching made it possible to keep a
>>        PDP-10 busy
>>        servicing all those Users and minimize the costs of everything,
>>        including those expensive communications circuits.  This was
>>        circa
>>        1980. Users could efficiently share expensive communications, and
>>        expensive and distant computers -- although I always thought
>>        ARPA's
>>        choice to use a computer 3000 miles away was probably more to
>>        demonstrate the viability of the ARPANET than because it was
>>        cheaper
>>        than using a computer somewhere near DC.
>>
>>
>>    The choice of USC-ISI in Marina del Rey was due to other
>>    factors.  In 1972, with ARPA/IPTO (Larry Roberts) strong support,
>>    Keith Uncapher moved his research group out of RAND.  Uncapher
>>    explored a couple of possibilities and found a comfortable
>>    institutional home with the University of Southern California
>>    (USC) with the proviso the institute would be off campus. 
>>    Uncapher was solidly supportive of both ARPA/IPTO and of the
>>    Arpanet project.  As the Arpanet grew, Roberts needed a place to
>>    have multiple PDP-10s providing service on the Arpanet.  Not just
>>    for the staff at ARPA but for many others as well.  Uncapher was
>>    cooperative and the rest followed easily.
>>
>>    The fact that it demonstrated the viability of packet-switching
>>    over that distance was perhaps a bonus, but the same would have
>>    been true almost anywhere in the continental U.S. at that time.
>>    The more important factor was the quality of the relationship. 
>>    One could imagine setting up a small farm of machines at various
>>    other universities, non-profits, or selected for profit companies
>>    or even some military bases.  For each of these, cost,
>>    contracting rules, the ambitions of the principal investigator,
>>    and staff skill sets would have been the dominant concerns.
>>
>>    Steve
>>
>
>
>
> -- 
> Please send any postal/overnight deliveries to:
> Vint Cerf
> 1435 Woodhurst Blvd
> McLean, VA 22102
> 703-448-0965
>
> until further notice
>
>
>

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