Return-path: Received: from smtp.codeaurora.org ([198.145.29.96]:40474 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752648AbcKGOKZ (ORCPT ); Mon, 7 Nov 2016 09:10:25 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Date: Mon, 07 Nov 2016 19:40:24 +0530 From: Ashok Raj Nagarajan To: Ben Greear Cc: Johannes Berg , Ashok Raj Nagarajan , linux-wireless@vger.kernel.org, ath10k@lists.infradead.org Subject: Re: [PATCH 1/2] cfg80211: Add support to set tx power for a station associated In-Reply-To: <579F4E4E.80103@candelatech.com> References: <1465926256-6463-1-git-send-email-arnagara@qti.qualcomm.com> <1467110918.2493.9.camel@sipsolutions.net> <1cb3e2cc49b433fe5ed834a33adf64b6@codeaurora.org> <1470043740.3389.10.camel@sipsolutions.net> <579F4E4E.80103@candelatech.com> Message-ID: <8908f6e7bb8ca043fbeb07ee8b004e8f@codeaurora.org> (sfid-20161107_151029_473897_72389CFF) Sender: linux-wireless-owner@vger.kernel.org List-ID: On 2016-08-01 18:57, Ben Greear wrote: > On 08/01/2016 02:29 AM, Johannes Berg wrote: >> >>> Sure.. First use case will be to help with the problem of legacy >>> client devices that roam across multiple APs. It is a classic >>> enterprise Wi-Fi AP problem, often managed by a "network controller" >>> unit that is connected to all the APs. >>> The problem is how to handle seamless handoff of clients between >>> multiple APs while maximizing the client throughput and minimizing >>> disruption of IP application services like VoIP calls and video >>> streaming. A legacy client will often hold onto an AP association, >>> even down to 1 Mbps as it roams away. Instead, if the AP can >>> recognise that the client RSSI (and therefore throughput) is poor, it >>> can "drop" the Tx power significantly (just to that client) such that >>> it forcesthe client to look for a better, closer, and therefore >>> higher-throughputassociation. It would "give it a kick" without >>> blacklisting it. It just needsto hold the power low for the small >>> amount of time it takes to convince it to go away. >> >> Not sure that *works* since implementations may just compare beacon >> signal strength and hold on to the AP based on that, but it does seem >> like a reasonable use case. > > How is that better than just kicking the station deliberately and/or > refusing to send frames to it at all? > Ben, deliberately kicking out the station can potentially cause the black listing behaviour on the client side and results in connection failures. Each client handles the kickout logic differently. Reducing the tx power, causes the station to trigger its roaming algorithm. >> >> How would this interact with automatic adjustment though? >> Johannes, In the case of manual intervention by user, the firmware will check three values - regulatory domain, automatic tx power and user entered value. System will always cap to the minimum of these values and see to that we do not exceed the regulatory power limits. If there are no more comments I will resent this patch series after rebase. Thanks, Ashok >> johannes >> >> -- >> To unsubscribe from this list: send the line "unsubscribe >> linux-wireless" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >>