[ih] Baran and Davies and respetive roles in Apra design
mbaer at cs.tu-berlin.de
Fri Mar 20 08:48:58 PDT 2009
An aside: The Kleinrock book also features a little section somewhere in
the beginning on how message switching in the telegraph system worked,
including priority schemes and error recovery.
Basically, they just had huge "buffers" and the internal switching speed
was a lot faster than the line / line out speeds. And if I recall
correctly, priority messages triggered an alarm upon which a human
operator would simply take the message and put it right in the front of
the proper outgoing queue. The processes were gradually automated.
The reference he in turn points to is Gilbert S. Vernam, Automatic
Telegraph Switching System Plan 55-A, Western Union Technical Review,
Vol. 12 No. 2 April 1958, Pages 37--50.
Vint Cerf wrote:
> yes of course we did know about "torn tape" and also about message
> switching in the form of AUTODIN.
> If you look at Len Kleinrock's book that emerged from his dissertation
> it was about stochastic flow and delay in message switched systems. An
> ARPANET innovation was to break messages up into "packets" for
> purposes of transmission to reduce transmission delay which was
> significant over low speed backbone trunks available at the time.
> Also, for purposes of noise resistance, the shorter packets had a
> higher probability of arriving intact than long messages.
> Communication Nets: Stochastic Message Flow and Delay
> This text develops a queuing theory model of communications nets, with
> realistic assessments that will benefit those working with computers
> and other communications systems. Topics include optimal channel
> capacity assignment, effect of priority and other queue disciplines,
> choice of routine procedure, fixed-cost restraint, and design of
> topological structures. 1964 edition.
> Publisher: Dover Publications
> ISBN: 0486458806
> EAN: 9780486458809
> No. of Pages: 209
> Vint Cerf
> 1818 Library Street, Suite 400
> Reston, VA 20190
> vint at google.com
> On Mar 20, 2009, at 12:40 AM, Larry Press wrote:
>>> Donald also contributed the term "packet" into the literature.
>> I am still curious -- did you all know about routing of telegrams
>> using torn paper tape, and, if so, did that have anything to do with
>> the idea of packet switching?
mbaer at csail.mit.edu
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