Xref: utzoo comp.dcom.modems:7148 comp.unix.questions:26663
Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!zephyr.ens.tek.com!tektronix!nosun!qiclab!m2xenix!quagga!ccfj
From: ccfj@quagga.uucp (F.F. Jacot Guillarmod)
Newsgroups: comp.dcom.modems,comp.unix.questions
Subject: uucp throughput on international link using Multi-Tech V.32
Keywords: speed speed speed
Message-ID: <1990Nov1.203225.14074@quagga.uucp>
Date: 1 Nov 90 20:32:25 GMT
Organization: Rhodes University, Grahamstown RSA
Lines: 41

I am getting about 500 cps transfer rate on a long distance (South Africa
to U.S.) uucp dialup link.  Locally, I am using a Multi-Tech V.32 modem, 
and the site in the U.S is using a Telebit T2500.  My dialler program 
is a version hacked from the Hayes2400 dialler.

The local system is a 386 clone running SCO Xenix 2.3.2, and the uucico
(which supports only 'g' protocol) has been modified to use a window
size of 7 - this change increased throughput from about 220 cps to the
present levels.  And, yes, I am driving my serial line to the modem at
19.2 kb!

Questions: 

a) is 500 cps over such a link expected, or is better throughput  
   possible?

b) if better performance is possible, how can it be attained?  My news
   feed is batched/compressed, and I am using smail 3.1 to compress and
   batch normal mail as well.

c) if this performance is about what can be expected, can anybody give
   an explanation of why faster transfer just doesn't happen?  Our
   local PTT is willing to assist, but I need to know what to ask
   them.

d) does anybody have a 'genuwine' Multi-Tech V.32 dialler program they
   are willing to share?  Particularly one that uses parameter tailored 
   for talking to Telebits...

e) if you could start from scratch, what modems would you use to
   maximize the speed of such a link?  Would V.42 make any difference, 
   given that the files to be transferred are already compressed?
   The reasoning behind this question is that an improvement in the
   performance translates into hard cash, and could write off the
   cost of new hardware in a few months.

Thanks in advance for any enlightenment on these points.

-- 
 F.F. Jacot Guillarmod - Computing Centre - Rhodes University - Grahamstown
 Internet: ccfj.quagga@f4.n494.z5.fidonet.org  uucp: ..!m2xenix!quagga!ccfj