Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750820AbWAPR2x (ORCPT ); Mon, 16 Jan 2006 12:28:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750770AbWAPR2w (ORCPT ); Mon, 16 Jan 2006 12:28:52 -0500 Received: from rrcs-24-73-230-86.se.biz.rr.com ([24.73.230.86]:5282 "EHLO shaft.shaftnet.org") by vger.kernel.org with ESMTP id S1750760AbWAPR2v (ORCPT ); Mon, 16 Jan 2006 12:28:51 -0500 Date: Mon, 16 Jan 2006 12:28:17 -0500 From: Stuffed Crust To: Sam Leffler Cc: Jeff Garzik , Johannes Berg , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: wireless: recap of current issues (configuration) Message-ID: <20060116172817.GB8596@shaftnet.org> Mail-Followup-To: Sam Leffler , Jeff Garzik , Johannes Berg , netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20060113195723.GB16166@tuxdriver.com> <20060113212605.GD16166@tuxdriver.com> <20060113213011.GE16166@tuxdriver.com> <20060113221935.GJ16166@tuxdriver.com> <1137191522.2520.63.camel@localhost> <20060114011726.GA19950@shaftnet.org> <43C97605.9030907@pobox.com> <20060115152034.GA1722@shaftnet.org> <43CAA853.8020409@errno.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="K8nIJk4ghYZn606h" Content-Disposition: inline In-Reply-To: <43CAA853.8020409@errno.com> User-Agent: Mutt/1.4.2.1i X-Greylist: Sender is SPF-compliant, not delayed by milter-greylist-2.0.2 (shaft.shaftnet.org [127.0.0.1]); Mon, 16 Jan 2006 12:28:18 -0500 (EST) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3081 Lines: 78 --K8nIJk4ghYZn606h Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Jan 15, 2006 at 11:53:55AM -0800, Sam Leffler wrote: > The above is a great synopsis but there is more. For example to support= =20 > roaming (and sometimes for ap operation) you want to do background=20 > scanning; this ties in to power save mode if operating as a station.=20 Opportunistic roaming is one of those things that has many knobs to=20 twiddle, and depends a lot on the needs of the users.=20 But we're not actually in powersave mode -- the 802.11 stack can spit out the NULL frames to tell the AP to buffer traffic for us. This is=20 trivial to do. Scans should be specified as "non-distruptive" so the hardware driver has to twiddle whatever bits are necessary to return the hardware to the same state that it was in before the scan kicked in. Beyond that, the scanning smarts are all in the 802.11 stack. The driver should be as dumb as possible. :) Background scanning, yes -- but there are all sorts of different thresholds and types of 'scanning' to be done, depending on how disruptive you are willing to be, and how capable the hardware is. Most thin MACs don't filter out foreign BSSIDs on the same channel when you're joined, which makes some things a lot easier. > Further you want to order your channel list to hit the most likely=20 > channels first in case you are scanning for a specific ap--e.g. so you=20 > can stop the foreground scan and start to associate. =20 With my scenarios, the driver performs the sweep in the order it was=20 given -- if the hardware supports it, naturally. > In terms of beacon miss processing some parts have a hardware beacon > miss interrupt based on missed consecutive beacons but others require > you to detect beacon miss in software. Other times you need s/w bmiss > detection because you're doing something like build a repeater when > the station virtual device can't depend on the hardware to deliver a > bmiss interrupt. Of course. The stack is going to need a set of timers regardless of the=20 hardware's capabilities, but having (sane) hardware beacon miss=20 detection capabilities makes it a bit more robust. =20 > Scanning (and roaming) is really a big can 'o worms. Oh, I know. I've burned out many brain cells trying to build=20 supportable solutions for our customers. =20 - Solomon --=20 Solomon Peachy ICQ: 1318344 Melbourne, FL =20 Quidquid latine dictum sit, altum viditur. --K8nIJk4ghYZn606h Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (GNU/Linux) iD8DBQFDy9exPuLgii2759ARAqTTAKDCrL0V0RUN98p5VmCHz/OCn2kQxwCZAbVB HTYySueDVuslKUtcY9u2WUM= =gnRY -----END PGP SIGNATURE----- --K8nIJk4ghYZn606h-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/