From owner-freebsd-mobile  Tue Oct 24  8:54: 5 2000
Delivered-To: freebsd-mobile@freebsd.org
Received: from martens.math.ntnu.no (martens.math.ntnu.no [129.241.15.250])
	by hub.freebsd.org (Postfix) with SMTP id AD1D837B479
	for <freebsd-mobile@freebsd.org>; Tue, 24 Oct 2000 08:54:02 -0700 (PDT)
Received: (qmail 12812 invoked from network); 24 Oct 2000 15:54:01 -0000
Received: from martens.math.ntnu.no (HELO localhost) (13799@129.241.15.250)
  by martens.math.ntnu.no with SMTP; 24 Oct 2000 15:54:01 -0000
To: freebsd-mobile@freebsd.org
Cc: alex@astro.su.se
Subject: Re: Linksys PCMCIA
In-Reply-To: <Pine.GSO.4.10.10010212001260.9733-100000@dioscuri>
References: <Pine.GSO.4.10.10010212001260.9733-100000@dioscuri>
X-Mailer: Mew version 1.94.2 on Emacs 20.6 / Mule 4.0 (HANANOEN)
X-URL: http://www.math.ntnu.no/~hanche/
Mime-Version: 1.0
Content-Type: Text/Plain; charset=us-ascii
Content-Transfer-Encoding: 8bit
Message-Id: <20001024175401N.hanche@math.ntnu.no>
Date: Tue, 24 Oct 2000 17:54:01 +0200
From: Harald Hanche-Olsen <hanche@math.ntnu.no>
X-Dispatcher: imput version 20000228(IM140)
Lines: 34
Sender: owner-freebsd-mobile@FreeBSD.ORG
Precedence: bulk
X-Loop: FreeBSD.org

+ Alexey Koptsevich <alex@astro.su.se>:

| Hello,
| 
| I see that "LINKSYS EtherFast 10/100" is supported by PAO.
| But Linksys offers at least 4 such cards:
| 
| PCMPC100 - EtherFast 10/100 PCMCIA Card
| http://www.linksys.com/products/product.asp?prid=41&grid=11

I can at least tell you that the above works, since I use it in my own
Dell 3500.  I run just plain vanilla 4.1-RELEASE.

I have run into one problem at home though:  When I connect my
stationary PC (also running 4.1-RELEASE) and the laptop back-to-back,
file transfers from laptop to stationary works fine, but the other way
I get 20-30% packet loss and correspondingly horrible transfer times
if I run at 100 Mbit/s.  If I force the network card on the stationary
PC to 10 Mbit/s the Linksys card follows suit automatically, and all
is well.  At work the problem does not yet appear because our network
is still mostly 10 Mbit/s.

I have come to believe that the problem is not so much the high bit
rate, but rather the arrival of data at a rate of several packets per
millisecond, possible with a buffer overflowing somewhere, or
interrupts getting lost, or whatever the heck.  For if I run a ping -f
against the machine, virtually no packets are lost.

Maybe there is a way to artificially slow the sender down a bit, so
this does not happen?  I wonder if the problem would go away if the
laptop declared a smaller TCP window, for example.  Except I don't
know how to tell it to do so.  Any other tricks?

- Harald


To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-mobile" in the body of the message