WiFi Data Rates on NanoNote and SDW823 ??

Werner Almesberger werner at openmoko.org
Fri Jan 7 01:32:26 EST 2011


J??rg Conradt wrote:
> TCP is a protocol that corrects errors and re-sends data; so here the
> throughput shall even be lower than on UDP

This depends on how you're testing. TCP also does congestion control.
Application-to-application throughput with UDP can be lower than with
TCP if there's congestion somewhere along the way and data on which
you've already spent resources is lost.

There are other things that can go wrong, but that's one I'd look for
first if UDP is consistently slower than TCP.

> I don't know of a program to test throughput;

My favourite is ttcp: http://en.wikipedia.org/wiki/Ttcp
Minimum overhead and easy to use.

> So e.g. use "scp" to copy a large file

With "scp", a lot of other effects enter the picture, e.g., encryption
overhead and storage I/O. Whether this is good or bad depends on your
exact usage scenario.

Something else to consider when assessing wireless performance is the
environment you expect to operate in. E.g., will you have the ether to
yourself, perfectly oriented antennas, with clear line of sight
communication over a short distance, or will the conditions be less
friendly ?

- Werner




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