From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]:65206 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753606Ab3C1XYM (ORCPT ); Thu, 28 Mar 2013 19:24:12 -0400 Message-ID: <1364511671.3226.22.camel@dcbw.foobar.com> (sfid-20130329_002416_969233_3053020D) Subject: Re: [RFC V2] cfg80211: introduce critical protocol indication from user-space From: Dan Williams To: Johannes Berg Cc: Arend van Spriel , Adrian Chadd , Felix Fietkau , linux-wireless@vger.kernel.org, Ben Greear Date: Thu, 28 Mar 2013 18:01:11 -0500 In-Reply-To: <1364510646.10397.81.camel@jlt4.sipsolutions.net> References: <1364472669-5629-1-git-send-email-arend@broadcom.com> <1364487476.10397.23.camel@jlt4.sipsolutions.net> <5154B347.9080904@broadcom.com> <1364506118.10397.29.camel@jlt4.sipsolutions.net> <1364510577.3226.7.camel@dcbw.foobar.com> <1364510646.10397.81.camel@jlt4.sipsolutions.net> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Thu, 2013-03-28 at 23:44 +0100, Johannes Berg wrote: > On Thu, 2013-03-28 at 17:42 -0500, Dan Williams wrote: > > > > Well, you can do DHCP a second or so, I'd think? And EAPOL much quicker, > > > of course. I don't really see any reasonable minimum time? We might want > > > to enforce a max though, maybe. > > > > Not quite. A lot is dependent on the server itself, and I've had users > > on university and corporate networks report it sometimes takes 30 to 60 > > seconds for the whole DHCP transaction to complete (DISCOVER, REQUEST, > > OFFER, ACK). Sometimes there's a NAK in there if the server doesn't > > like your lease, which means you need another round-trip. So in many > > cases, it's a couple round-trips and each of these packets may or may > > not get lost in noisy environments. > > Oh, yes, of course. However, we're talking about optimising the good > cases, not the bad ones. Think of it this way: if it goes fast, we > shouldn't make it slow by putting things like powersave or similar in > the way. If it's slow, then it'll still work, just slower. But when > "slower" only means a few hundred milliseconds, it doesn't matter if > everything takes forever (30-60 secs) True, but at least 4 or 5 seconds is the minimum time I'd recommend here for DHCP. Dan