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I am building a wireless link between two points using Wireless-N standard. To determine the best position of the antennas, there is a signal strength indicator on the antennas. The problem is the link strength doesn't always correspond to link throughput.

I'm looking for an offline version of http://www.speedtest.net or http://www.speakeasy.net/speedtest/ that can do continous monitoring of throughput.

Ideally, I would run this software and monitor increase/decrease of throughput while repositioning the antenna.

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4 Answers 4

up vote 3 down vote accepted

Sounds like a job for iperf.

Or a flood ping.

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Flood ping is interesting, easy enough to do without any additional software. Thanks. –  Adrian Godong Dec 5 '10 at 4:41
If that works, I'd appreciate the check mark. I'm not too proud to ask. –  Jed Daniels Dec 5 '10 at 6:04
i gave you the check mark myself - as its a good answer. Biggest thing in wireless is he may want to check more than just tcp - so making sure he does some UDP testing would be wise... those tests will really show you where things are good vs bad. –  Glenn Kelley Dec 5 '10 at 6:33

iPerf would do much better than would a file on a webserver. Few reasons - including mod_throttle, bandwidth etc - coming from the server itself.


Jed hit the nail on its head suggesting IPERF - here is why:

Iperf is a tool to measure the bandwidth and the quality of a network link. If you would combine IPERF w/ Jperf you have a great graphical interface to use while playing with your link.

A single file coming from a webserver would not be able to give you a clear picture since there is no way to test the quality of the link. The quality of the link is important not just speed.

Using IPERF - you can test the Latency (response time or RTT) - by uinsg the Ping command. You can also look at any Datagram loss using an IPERF UPD test - heck... Jitter (the variation of the latency across the link) can be measured as well with an IPerf UDP test.

The quality of a link can be tested as follows: - Latency (response time or RTT): can be measured with the Ping command. - Jitter (latency variation): can be measured with an Iperf UDP test. - Datagram loss: can be measured with an Iperf UDP test.

Iperf will also allow you to test bi-directionally which a webserver will not.

Let us know if you need help using IPERF - just respond w/ the operating system your using on each system on both sides of the link.

One last note - what gear are you using - just the radios or spectrum analyzation tools?

Your WIFI gear may be able to help you a great deal.


I am assuming you are using 2.4GHZ yes? Reason I ask is that if you are using some of the higher frequencies (such as 5.xGHZ - which MAC's support) they do a good job at closer distances - give excellent speeds BUT hate things like walls in their way.

If you have a spectrum analyzer (ps most all of Ubiquity gear www.UBNT.com have this built in) will help you a great deal.

For example - you may find that channel 1 vs channel 8 is a better choice.
We have some links using 2.4Ghz going over a great distance (15+ miles at some places) - and the only variation on speed is the channel - thus allowing us to break apart a great deal of interference. Speed Example 1

versus where the CCQ (link quality) is lower overall but we see more bandwidth and a better db level.

Speed Example different channel

In a small office - warehouse etc - channels will make a huge difference, especially if others are close this can really make a difference.

The point here is simple - Location of the antenna's is not the only factor. If you would agree that using good equipment can make the world of difference than it is fair to say Using a spectrum analyzer will make a Universe of difference.

Waterfall Chart:

Ubiquity Waterfall

This time-based graph shows the aggregate energy collected since the start of an AirView / spectrum analyzer session, over time for each frequency. The power of the energy in dBm is shown across the frequency span and one row is inserted in this graph every few seconds.



It is a great thing to let this run for a long time to see what is happening on the connection from a radio perspective.

Channel Usage Chart:

Channel Usage Chart


Wafeform Chart:

Waveform Chart Example


Real Time Chart:

This is most likely what you want the most...

Real Time Radio Chart


This tool runs for under $100 online - just do a froogle search for Airview. Combined with IPERF - you can have a really great network for not much work or hassle.

If this has helped - please vote this answer up a notch.

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Put a really big data file on a local webserver, then use wget to download the file. By default, wget displays a pretty good speed indicator while it's downloading, e.g.:

$ wget -O - http://xxx.xxx.xxx.xxx/really-big-file.bin >/dev/null
--2010-12-04 20:31:32--  http://xxx.xxx.xxx.xxx/really-big-file.bin
Connecting to xxx.xxx.xxx.xxx:80... connected.
HTTP request sent, awaiting response... 200 OK
Saving to: `STDOUT'

11% [===>                                   ] 12,342,529  1.01M/s  eta 89s
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I was thinking something like this, but assuming it's 100Mbps link then 1Gb file will be done in 10 seconds. There's also disk read time which shouldn't be taken into account. –  Adrian Godong Dec 5 '10 at 4:38
@Adrian: So try a 10GB file. Or call wget over and over in a loop. Or hack together an ad hoc server with a few lines of Python to stream pseudo-random data in response to an HTTP GET request. Use your imagination! I don't understand your "disk read time" objection, though. –  Steven Monday Dec 5 '10 at 5:02

Another option is ttcp. Not as fancy as iperf, but sometimes it's all you need.

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