Re: CFP-End

From: Jouni Malinen (
Date: 2002-07-30 09:50:22 UTC

On Mon, Jul 29, 2002 at 03:47:35PM -0700, Omesh Tickoo wrote:

> I needed some input on how HostAP handles CFP. My
> understanding is that HostAP does not have the CF poll
> functionality built in. It uses the default value of 0
> for length of the CFP. I am implementing the CFP
> handling (esp. the PC polling mode) for the hostAP.

Host AP driver has no code for CFP and if I remember correctly, neither has station firmware support for this. I haven't really tested this, since there does not seem to be any mechanism for configuring or controlling the firmware to do anything about the CF intervals etc.

Of course I would like to be proven wrong on this.. Anyway, I would first check whether this really can be done before using much effort implementing support for some frame subtypes related to CFP handling.

> While I am working on it it will be great if someone
> can point out if the CF-Poll frames can actually be
> handled by the driver with on Prism2 in HostAP mode or
> these frames are handled by the firmware. From Prism2
> documentation it looks like if I put the chipset in
> HostAP mode I should get all the Poll requests
> directed to the driver.

You will certainly get _PS_ poll requests (i.e., power saving). In addition, CF related frames indicate CF period end and polls etc., as control and data frame subtypes. I would guess that at least the info from data frames could be available to the host system, but I would not be so sure about the control frames. Anyway, even with these frames, I would assume that it is impossible to really use CFP without modifying the firmware.

Jouni Malinen                                            PGP id EFC895FA

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