Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!ut-emx!walt.cc.utexas.edu!petrilli
From: petrilli@walt.cc.utexas.edu (Chris Petrilli)
Newsgroups: comp.mail.uucp
Subject: Re: How efficient/fast is uucp?
Message-ID: <36650@ut-emx.UUCP>
Date: 23 Aug 90 14:29:18 GMT
References: <8464@pitt.UUCP> <1556.26d282ea@dcs.simpact.com>
Sender: news@ut-emx.UUCP
Reply-To: petrilli@walt.cc.utexas.edu (Chris Petrilli)
Organization: The University of Texas at Austin
Lines: 33

In article <1556.26d282ea@dcs.simpact.com> jeh@dcs.simpact.com writes:
>In article <8464@pitt.UUCP>, jonathan@cs.pitt.edu (Jonathan Eunice) writes:
>> How efficient is/are the protocol(s) used by uucp?  How do they compare
>> with zmodem?  For some reason (not based on anything resembling
>> knowledge), I have the impression that uucp uses crufty, old, slow
>> protocol(s).  Am I in left field?  
>
>Yes, you're in left field.  
>
>The worldwide de facto standard for uucp dialup with 'g' protocol uses packets
>with 64-byte data fields and six-byte headers, thus achieving about 90%
>utilization of the available bandwidth.  Many modern uucps can be configured to
>support larger packets, up to 4096 bytes, which squeezes the "overhead" down to
>almost nothing, but at the expense of MUCH greater retransmission cost when
>errors occur.  Some sites with reliable connections run with 1K packets, which
>seems to be a good compromise.  
>

One thing that was forgotten is the availability and use of the Telebit
Trailblazer modem.  The Trailblazer implements UUCP g-protocol in
hardware, and strips all incoming framing information, and adds it when
it gets there.  My timings/measurements, seem to say it is about 99%
efficient, which means at "9600bps" (really 11K on a trailblazer, but
for example), you would get about 9504cps without the Trailblazer, but
with it you would get 9598cps or so... it helps alot on long distance
transmissions.


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