[ih] Question re rate of growth of the Arpanet

[Jack Haverty]

The ICCC conference in 1972 at the Washington Hilton was the "coming out 
party" for ARPANET.  I was one of the crew setting up in the ballroom 
where live demos would be used by the public.  I had never seen an IMP 
actually hooked up, so I volunteered to help the Telco guy when he 
arrived to get the "wideband circuit" in place - i.e., he had orders to 
"provision" the circuit.

My expectations were to see some kind of massive cable, with robust 
military grade connectors, and the very professional "cable run" 
appropriate for a "wideband circuit".  But what I actually saw was the 
tech using a spool of wire, which looked like it had been used many 
times before, and connecting its ends to screw terminals in a box on the 
wall, just like you would then hook up a regular phone line.   IIRC 
there was only a single circuit to the IMP (actually it was a TIP).

That makes me wonder now if the ICCC'72 demo actually used a 50-kb 
circuit.  Was it possible to get "12 bonded channels" somehow over a 
single twisted pair?

Jack

On 4/21/25 11:40, Steve Crocker via Internet-history wrote:
> I may be wrong about 9.6.  It's what I recall when this was relayed to me,
> but I'd want to track down a more authoritative source.
>
> Re U.S. distances: In 1968 I was in Boston until May and then in Los
> Angeles.  The University of Utah was just barely beginning to come to
> people's attention in the computer science community.  When I mentioned the
> university to people in Boston, someone said it was near Los Angeles.  When
> I mentioned it to a friend in Los Angeles, she thought it was near Chicago
> :)
>
> Steve
>
>
> On Mon, Apr 21, 2025 at 2:33 PM John Day<jeanjour at comcast.net>  wrote:
>
>> theRoberts had originally planned to use 2.4Kbps lines. Roger Scantlebury
>> (and others) at the Gatlinburg Operating System Conference in the Fall of
>> 67 (it appears to have been one of *those* bar discussions) ;-) convinced
>> him that given NPL’s experience with their packet-switched network they had
>> found that that was way too slow and he should use 50Kbps.
>>
>> Both Baran and Davies independently had come to the conclusion that
>> 1.5Mbps would be best but it wasn’t available yet.
>>
>> There are two things I find amusing about this:
>> 1) The ARPANET would have worked at 2.4 or 9.6, etc. But would have been
>> deemed so slow to prove that the effort wasn’t really successful. At 50K,
>> we could really get work done. Not many systems could sustain that and
>> there weren’t many applications needing all of that. Using 50K was a much
>> larger part of the ARPANET’s success than we often give it credit for.
>>
>> 2) Roger’s experience was for the NPL campus network. I am not sure Roger
>> had any idea what 50K (which were expensive!) would do to Roberts budget
>> for a nation-wide network in the US.  ;-) At the time, most Europeans and
>> many East Coast Americans had no sense of distances in the US. (I remember
>> a tale of 3 IBMers sent from Poughkeepsie to Detroit to work on some
>> customer's system, who thought as long as they were that far West, they
>> could drive to Las Vegas for the weekend.) (!!) ;-) (31 hours now with
>> Interstates which were not complete then.)  Good thing ARPA’s pockets were
>> deep. ;-)
>>
>> O, and at that conference, Roger convinced Roberts to use packet
>> switching, which he had not heard of. (He did find Baran’s papers in a
>> stack he hadn’t read when he got back to DC.)
>>
>> Both are great serendipity, that had a profound effect and for the most
>> part lost in history. I always find these kinds of things delightful.
>>
>> Take care,
>> John
>>
>>> On Apr 21, 2025, at 14:08, the keyboard of geoff goodfellow via
>> Internet-history<internet-history at elists.isoc.org>  wrote:
>>> steve, can you elucidate any history with respect to how/why the speed of
>>> 50 kb/s was chosen for the ARPANET lines?  were there great speeds
>>> available then?
>>>
>>> yours truly kinda (perhaps mistakenly) recalls these 50 kb/s "wideband
>>> circuits of the day" were primarily used for linking tv broadcast
>> affiliate
>>> stations to/with their motherships (cbs, nbc, abc, ...)?
>>>
>>> geoff
>>>
>>> On Mon, Apr 21, 2025 at 7:26 AM Steve Crocker via Internet-history <
>>> internet-history at elists.isoc.org> wrote:
>>>
>>>> Thanks for the pointer to RFC 597.
>>>>
>>>> As I looked at it, an aspect I hadn't considered before came to mind.
>>>>
>>>> Installation of an IMP required provisioning 50 kb/s lines to two or
>> three
>>>> other points.  In the early days, we installed roughly a new IMP once a
>>>> month.  (The lead time for ordering 50 kb/s lines from AT&T was NINE
>>>> months.)
>>>>
>>>> Once an IMP was installed, new hosts could be added to the IMP as
>> quickly
>>>> as the site could build or obtain the host-IMP interface and write or
>>>> obtain the software for their operating system.
>>>>
>>>> If anyone has the dates for each of the hosts, it would be interesting
>> to
>>>> compare the growth of IMPs vs growth of hosts.
>>>>
>>>> Steve
>>>> --
>>>> Internet-history mailing list
>>>> Internet-history at elists.isoc.org
>>>> https://elists.isoc.org/mailman/listinfo/internet-history
>>>>
>>>>
>>> --
>>> Geoff.Goodfellow at iconia.com
>>> living as The Truth is True
>>> --
>>> Internet-history mailing list
>>> Internet-history at elists.isoc.org
>>> https://elists.isoc.org/mailman/listinfo/internet-history
>>

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