Re: Tx Rate control in Master mode?

From: Jouni Malinen (
Date: 2002-03-12 12:48:03 UTC

On Tue, Mar 12, 2002 at 12:28:07AM -0800, David L. Sifry wrote:

> I'm scratching my head a bit - can anyone tell me why I can't get the
> bit rate over 2Mbps?

Have you checked, what the real used TX rate is?

> I try:
> iwconfig wlan0 rate 11M
> but no matter what I set the rate to, it seems fixed at 2Mbps. Is this
> a bug or a feature?

Assuming you get the TX speed from iwconfig output, it is a feature ;-) (if the real TX rate for all stations is only 2 Mbps, then its a bug)

In Host AP mode the driver adjust TX rate separately for each associated station and it is not that clear to convert that to one value. Use /proc/net/prism/wlan0/<sta mac addr> file to check the real TX rate (it has counters for each possible TX rate). Of course iwconfig could display something else (e.g., the maximum TX rate supported by the AP) since HFA384X_RID_CURRENTTXRATE is not necessarily valid in Host AP mode. Anyway, this value would be a bit bogus..

At the moment, forcing TX rate with iwconfig does not really do anything in Host AP mode. It may have some effect if you use firmware based TX rate controlling (iwpriv wlan0 txratectrl 1). However, station firmware does not seem to be very intelligent about TX rate controlling in Host AP mode and I'm therefore using driver based controlling for it.

Jouni Malinen                                            PGP id EFC895FA

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