[NTLUG:Discuss] OT: internet access/download speeds different between os

[Dan Carlson]

----- Original Message -----
From: <MontyS at videopost.com>
To: <discuss at ntlug.org>
Sent: Thursday, February 21, 2002 10:48 AM
Subject: [NTLUG:Discuss] OT: internet access/download speeds different
between os


> . . .
>  We have also gone to a web site that
> checks connect speeds, and it reports back 1.3Mbps.  It seems that
"bursts"
> of data, like surfing uncomplicated sites, is fine.  Only when we try to
> move moderate amounts of data does things fall apart.

> . . .

If not for the above, the first thing I'd recommend looking into are the
MTUs that the network interfaces on your various systems (and gateway) are
configured to use.  Perhaps the new provider requires a different MTU than
the old provider for optimal performance.  However, inappropriate MTUs
should be more of a problem on something like a bulk speed test, not less
of a problem.  Still, it might be worth looking into.  See if you can
recognize a pattern in the MTUs of the machines that perform well versus
those that don't.  Determining what MTU is being used on an interface on a
given OS can be an interesting exercise unto itself.

I ran into this issue a year or so ago on my GTE/Verizon DSL line.  It had
been performing up to the rated speed, but one day performance dropped
significantly, and I had not changed anything on my end.  After a lot of
benchmarking of different size ftp transfers to and from one of my ISP's
servers (i.e. something nearby, as far as routing goes), I was able to
determine that changing my gateway interface's MTU from its previous value
of 1500 to 1000 brought performance back to its original level.  Apparently
something changed somewhere between my DSL modem and the ISP, although I
was not able to find anyone who could tell me what they changed.

Dan Carlson