Date: Wed, 4 Dec 1996 00:26:47 +0100 (GMT+0100) From: af@biomath.jussieu.fr (Alain FAUCONNET) To: msmith@revolution.3-cities.com (Mark D. Smith) Cc: wes@bogon.net, questions@FreeBSD.ORG Subject: Re: Why such poor PPP throughput? Message-ID: <199612032326.AA08027@iaka.biomath.jussieu.fr> In-Reply-To: <199612032238.OAA23824@revolution.3-cities.com> from "Mark D. Smith" at "Dec 3, 96 02:38:09 pm"
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Mark D. Smith wrote / a ecrit:
> >
> > 'Lo all. I've been noticing over the past few months that the receive
> > speed on my dedicated 28.8 PPP line has been less than stellar. For
> > example, when ftping a pre-compressed file from my ISP (1 hop), I get
> > a maximum of 2.14 kb/sec throughput, with an average of about 1.94
> > kb/sec.
> >
> > I've talked to my ISP about it several times but they're sure it's not
> > happening at their end. All that they've been able to determine is
> > that I'm registering lots of incoming packet errors at the terminal
> > server (which I can verify -- see below), that my connection speed
> > seems to retrain down to ~24.4 alot, and that no other subscribers
> > have mentioned low transfer speeds as being a problem.
>
> Sounds like your phone line may be noisy. I had that problem some time
> back.
The noisy line could account for the retrain but probably not for the
input errors. Nearly all modern modems do error correction, which
means that data arrive slower to your machine if the line is noisy,
but they are supposed to arrive undamaged.
I would carefully check input flow control i.e. can your computer
throttle data coming from the modem ? (check modem settings for
CTS/RTS flow control, check tty setting and PPP options for hardware
flow control too).
Now if the server of your ISP spits out data at 38.4k to a modem that
can't accept it at that rate due to poor phone line quality, then I
hope that their DTE-modem output flow control does work either...
Other customers having better phone line quality might not need it as
much as you do.
_Alain_
--
Alain FAUCONNET Ingenieur systeme - System Manager AP-HP/SIM
Public Health 91 bld de l'Hopital 75013 PARIS FRANCE
Medical Computing Research Labs Mail: af@biomath.jussieu.fr
Tel: (+33) (0)1-40-77-96-19 Fax: (+33) (0)1-45-86-80-68
I've RTFMed. It says: "Refer to your system administrator"
But... I *am* the system administrator :-]
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