Max throughput with XO on 802.11G

John Watlington wad at laptop.org
Sat Nov 14 00:43:19 EST 2009


Yep.  There is a lot of overhead, and there are also limitation in  
the connection between the host
and the network interface.   You should upgrade to a newer OS image,  
however,   You want to have
the latest libertas firmware (this may not improve the performance,  
but it makes your results more relevant...)

At best, I expect to see around 20 Mbps.  12 - 16 Mbps isn't bad.    
On XO-1.5, the SDIO interface
limits you to around 18 Mbps tops.

Cheers,
wad

On Nov 13, 2009, at 12:06 PM, Andrés Nacelle wrote:

> Hello fellows, I´ve been working some time ago on the maximum  
> throughput you can get from an XO on it´s wireless and I got some  
> interesting results, on which I still have to work but I would like  
> to share with you to know if I´m trying to invent the wile again.  
> But first the conditions, I´ve been using an XO 1.0 with Q2E35  
> firmware and image 801, the distance to the AP is less than 3m and  
> the noise lv -91dBm.
>
> Now the interesting part, the test and the data.
> Basically what I did was measure the throughput that a XO can reach  
> using for this the iperf.
> I configured an AP in order to only admit the maximum rate (11Mbps)  
> from 802.11b and everything went ok, the max throughput achieved  
> was 5,9 Mbps when the max thr with a 1500 Bytes package size is 6,3  
> Mbps.
> Now comes the interesting, when I did the same with 802.11g setting  
> the rate at 54 Mbps te XO reached 14,5 Mbps which belongs to a  
> 24Mbps rate, so I tried to do the same in that rate but the throughput
> was 10.0 Mbps. During the measures I watched the connection rate on  
> the XO and was the proper one.
> My theory (and yet to check by package capture ) is that the  
> maximum size package is not getting above 600 bytes. I did the math  
> and plotted throughput vs package size for different rates and the  
> results are congruent with my theory.
> After making some captures I´ll tell you.
>
> Bye
>
>
> -- 
> Andres Nacelle
> Plan Ceibal - Investigación y Desarrollo
> Avda. Italia 6201
> Montevideo - Uruguay.
> Tel.: 601 57 73 Int. 213
> E-mail : anacelle at plan.ceibal.edu.uy
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