Re: DTIM (Power Save Mode) w/ HostAP

> On Fri, Mar 07, 2003 at 12:50:05AM -0800, Matt Peterson wrote:
> > A compatibility issue arose from testing BSD HostAP mode with an Intel
> > Centrino 11b client.  (Stay tuned at your favorite airport, net coffee
> > shop, etc. on March 12th for all the marketing foo on Centrino.)  When
the
> > NIC in question (rumored to be a recycled Symbol MAC) has power
management
> > enabled (the big selling point of Centrino silicon suite), poll requests
> > aren't processed correctly by the HostAP mode driver.  Thus, the STA
keeps
> > sending re-tries (PS-Poll) to download its "buffered" data.
>
> With Prism, a host AP is responsible for detecting that a STA has switched
> to powersave mode and for queueing its packets until is PS-Polls.
>
> The NetBSD code does not detect power-saving STAs or queue their
> packets, so PS STAs will lose. Did FreeBSD add this function?
>

No, freebsd did not add that (yet).

> Sam Leffler has produced a mega-patch to the 802.11 framework that I
> *think* contains PS queueing. Failing that, my "jumbo" patch to NetBSD
> contained the beginnings of PS queueing, but it was clobbered by Atsushi
> Onoe's very fine 802.11 framework.
>

No, the patch I sent you did not include PS support.

> Maybe somebody out there knows off the top of their head
>
> 1 What are the timing requirements for answering PS-Polls? Can we
>   meet the requirements if the HostAP driver will not queue at least
>   one PS packet per STA and hold it until until that STA's PS-Poll?
>
> 2 Will the HostAP driver actually queue and hold one PS packet?
>

I believe Jouni Malinen's Linux hostap code supports PS-polls; not sure.  I
know he's done a bunch of similar "estorica" like fragmentation/reassembly.
It might be a good place to look.

    Sam

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