[60296] in North American Network Operators' Group
Re: testing bandwidth of big internet pipes
daemon@ATHENA.MIT.EDU (Stewart, William C (Bill), RTSLS)
Tue Aug 5 21:36:28 2003
Date: Tue, 5 Aug 2003 20:32:35 -0500
From: "Stewart, William C (Bill), RTSLS" <billstewart@att.com>
To: <nanog@trapdoor.merit.edu>, <arjan.lugtenberg@planet.nl>
Errors-To: owner-nanog-outgoing@merit.edu
I tend to think of T1 and E1 connections as small=20
(STM1s are starting to be big :-).
It's easy enough to test them if there's something fast enough to test =
to.
The two kinds of tests your customers are likely to care about are
- Is your connection to them really the speed it should be?
- Do you have enough upstream bandwidth for your traffic load?
There are lots of ways to get and measure a 2Mbps load -
- Most Cisco routers have "ttcp" client/server code,=20
http://www.cisco.com/warp/public/471/ttcp.html
http://www.netcordia.com/tnm/tnm31/ttcp.htm
and you can either talk to another Cisco or use a Windows or Linux PC.
- FTP on a Sun 3/60 a decade ago, or a Linux box with FTP or HTTP today,
and any medium-fast Windows machine with an FTP or HTTP client
that shows you download speed is usually a good demonstration.
(You need to ignore initial ramp-up time because of TCP slow-start.)
If you've got a spare PC you can hang off one of your routers,
run an FTP and HTTP server on it and keep a few "10MB.txt" type files =
on it.
- Qcheck is a nice friendly free client for Windows and other platforms
which does speed and latency tests using tcp, udp, and ping,
and can also be driven by their non-free testing systems.
http://www.ixiacom.com/enterprise/Qcheck.php
(Qcheck does use more PC CPU than simpler tools -=20
my 66MHz Pentium doorstop boxes could only do ~300-400 kbps,
but anything over about 500 MHz should do just fine.)
- A really *bad* method that's popular with some of my customers (:-)
is to use really big pings on a Cisco router.
There are lots of different reasons this tends to fail.
The second question is harder to answer, because you need a site
that's not in your network that can give a fast enough response
that the customer will feel happy, and I've found that it's often hard
to download files from public web sites at faster than 1-2 megabits per =
second,
because either the web site is <=3D T1, or it's large and shared by many =
users.
Linux distribution sites when there's nothing interesting being released
are usually good, but unfortunately mirror sites often mirror lots of =
things,
so you may have trouble finding a quiet one. =20
I don't remember if BitTorrent has a fancy user interface that
shows current download speed, but it's usually good at filling up
any symmetrical Internet pipe if there's something popular to download.
