Re: Problem with transfer rate.

From: Jouni Malinen (
Date: 2002-06-17 17:28:46 UTC

On Fri, Jun 14, 2002 at 08:10:12PM +0200, Samuel Partida wrote:

> iwconfig shows a transfer rate of 11mbps and a link of 72/92 but doing
> transfer of big files from one machine to another, i can't get more than
> 80kbyte/sec, i had the same problem trying from two conceptronics and
> i've tested it in Ad-Hoc mode even changing many settings with
> iwconfig like the freqs and channels and txpower and some more without
> having any solution.

I'm assuming that transfer was using TCP. Have you tested performance with UDP? I have seen some cases in which a Prism2-based cards have stopped ACKing received frames which will cause huge performance issues (all packets being retried many times). However, this should show up in the other end's kernel debug log (assuming you are using Host AP driver in both hosts) as TX Exc messages. Anyway, you might test setting maximum retry count to zero or one (iwconfig wlan0 retry 0) and check the performance with this configuration.

Raw 802.11 dump (e.g., with 3rd card in monitor mode) could be useful for determining the cause for the poor performance if there is no entries in dmesg output to help with this. I would check for ACKs and too frequent retries.

Jouni Malinen                                            PGP id EFC895FA

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