[ih] Question re rate of growth of the Arpanet

[John Day]

Yes, I thought so too.  My quoting 2.4 was based on the paper Roberts gave at the Gatlinburg conference.

Ah, so the government had a special tariff, so it wasn’t quite as expensive as I thought. Still far greater than a campus network, but better.  ;-)

> On Apr 21, 2025, at 14:32, Steve Crocker via Internet-history <internet-history at elists.isoc.org> wrote:
> 
> Geoff,
> 
> To add a bit more, I believe Larry Roberts was originally thinking in terms
> of 9600 baud lines.  However, he discovered the U.S. Government had access
> to a special Bell tariff for these 50 kb/s circuits.  As Vint said, the 50
> kb/s was implemented using twelve voice grade circuits and a Western
> Electric series 303A modem.  Bottom line, Larry found this item in the
> government catalog that provided this bandwidth and was within his budget.
> 
> Steve
> 
> 
> On Mon, Apr 21, 2025 at 2:11 PM Vint Cerf <vint at google.com> wrote:
> 
>> Best you could do with 12 3KHz bonded channels on a Bell 303 modem
>> 
>> V
>> 
>> Please send any postal/overnight deliveries to:
>> Vint Cerf
>> Google, LLC
>> 1900 Reston Metro Plaza, 16th Floor
>> Reston, VA 20190
>> +1 (571) 213 1346
>> 
>> 
>> until further notice
>> 
>> 
>> 
>> 
>> On Mon, Apr 21, 2025, 14:09 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
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>>>> 
>>>> 
>>> 
>>> --
>>> Geoff.Goodfellow at iconia.com
>>> living as The Truth is True
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>> 
> 
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