Re: [homenet] low latency handovers in wifi (was: New Version Notification for draft-barth-homenet-wifi-roaming-00.txt)

Alexandre Petrescu <alexandre.petrescu@gmail.com> Tue, 01 December 2015 15:45 UTC

Return-Path: <alexandre.petrescu@gmail.com>
X-Original-To: homenet@ietfa.amsl.com
Delivered-To: homenet@ietfa.amsl.com
Received: from localhost (ietfa.amsl.com [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 8A4C81ACD10 for <homenet@ietfa.amsl.com>; Tue, 1 Dec 2015 07:45:45 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.983
X-Spam-Level:
X-Spam-Status: No, score=-4.983 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_ADSP_CUSTOM_MED=0.001, FREEMAIL_FROM=0.001, HELO_EQ_FR=0.35, NML_ADSP_CUSTOM_MED=0.9, RCVD_IN_DNSWL_HI=-5, SPF_SOFTFAIL=0.665] autolearn=ham
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id dZu8xGFGADVE for <homenet@ietfa.amsl.com>; Tue, 1 Dec 2015 07:45:43 -0800 (PST)
Received: from cirse-out.extra.cea.fr (cirse-out.extra.cea.fr [132.167.192.142]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 6B5CF1ACD19 for <homenet@ietf.org>; Tue, 1 Dec 2015 07:45:43 -0800 (PST)
Received: from pisaure.intra.cea.fr (pisaure.intra.cea.fr [132.166.88.21]) by cirse.extra.cea.fr (8.15.2/8.15.2/CEAnet-Internet-out-2.4) with ESMTP id tB1FjfVl029584 for <homenet@ietf.org>; Tue, 1 Dec 2015 16:45:41 +0100
Received: from pisaure.intra.cea.fr (localhost [127.0.0.1]) by localhost (Postfix) with SMTP id E2935205A8F for <homenet@ietf.org>; Tue, 1 Dec 2015 16:52:17 +0100 (CET)
Received: from muguet2.intra.cea.fr (muguet2.intra.cea.fr [132.166.192.7]) by pisaure.intra.cea.fr (Postfix) with ESMTP id DAC41202D8D for <homenet@ietf.org>; Tue, 1 Dec 2015 16:52:17 +0100 (CET)
Received: from [127.0.0.1] (is227335.intra.cea.fr [10.8.34.184]) by muguet2.intra.cea.fr (8.15.2/8.15.2/CEAnet-Intranet-out-1.4) with ESMTP id tB1Fje4U014294 for <homenet@ietf.org>; Tue, 1 Dec 2015 16:45:41 +0100
From: Alexandre Petrescu <alexandre.petrescu@gmail.com>
To: homenet@ietf.org
References: <20151016113242.29159.37112.idtracker@ietfa.amsl.com> <5620E158.4000309@openwrt.org> <56265237.8020202@gmail.com> <56571260.6040504@globis.net> <alpine.DEB.2.02.1511261610310.24520@uplift.swm.pp.se> <56572539.8080802@mtcc.com> <alpine.DEB.2.02.1511301438500.24520@uplift.swm.pp.se> <CAA93jw5A-uLza2hRLkM7UnZQeMRwz069o4sb6GAx=hJgLj8i0A@mail.gmail.com> <alpine.DEB.2.02.1511301501100.24520@uplift.swm.pp.se> <CAA93jw604U+WYhEgFw4PAY4VeBSDb0dvz=5Bzc+3VWcTF3sT1g@mail.gmail.com>
Message-ID: <565DC0A4.4020707@gmail.com>
Date: Tue, 1 Dec 2015 16:45:40 +0100
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0
MIME-Version: 1.0
In-Reply-To: <CAA93jw604U+WYhEgFw4PAY4VeBSDb0dvz=5Bzc+3VWcTF3sT1g@mail.gmail.com>
Content-Type: text/plain; charset=windows-1252; format=flowed
Content-Transfer-Encoding: 8bit
Archived-At: <http://mailarchive.ietf.org/arch/msg/homenet/lINuZP5qprEbl3QQKfMkqFyEzts>
Subject: Re: [homenet] low latency handovers in wifi (was: New Version Notification for draft-barth-homenet-wifi-roaming-00.txt)
X-BeenThere: homenet@ietf.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: IETF Homenet WG mailing list <homenet.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/homenet>, <mailto:homenet-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/homenet/>
List-Post: <mailto:homenet@ietf.org>
List-Help: <mailto:homenet-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/homenet>, <mailto:homenet-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 01 Dec 2015 15:45:45 -0000


Le 30/11/2015 15:18, Dave Taht a écrit :
> On Mon, Nov 30, 2015 at 3:04 PM, Mikael Abrahamsson <swmike@swm.pp.se>; wrote:
>> On Mon, 30 Nov 2015, Dave Taht wrote:
>>
>>> Well, in the two or more radio (2.4 and 5ghz) case, you can easily roam
>>> between the two radios with many chipsets. Some chipsets only allow one
>>> active radio at a time, however.
>>
>>
>> Does this actually work in real life? Considering the solutions I found
>
> Using linux, with ath9k gear, worked for 7 years. On nearly everything
> else, rare.
>
>> doing my quick search, it seems the AP vendors are implementing all kinds of
>> solutions to trick the client that it's just one single large network with a
>> single AP, even though it's a lot of them.
>>
>> For instance:
>> https://help.ubnt.com/hc/en-us/articles/205144590-UniFi-What-is-Zero-Handoff-
>
> yes, it's a mess.

Parsing that URL... if one wants zero latency handoff in WiFi one tries 
to strip all link-layer messages (incl. security) and operate outside 
the context of a BSSID.

> It's even worse than that...
>
>>
>> So while I would prefer a solution in the end with make-before-break and
>> seamless handover without breaking the IP layer at all, this seems to
>> involve quite a lot of new functionality both from the Network (which is
>> doable) and from the client (also doable, but a lot harder, especially
>> within current charter).
>
> I would not mind at all if the ietf had a wg with the ieee and the
> wifi alliance and whoever else might care, to make wifi better in a
> huge variety of ways.

It's already ongoing in some groups at IETF, e.g. 6lo WG considering 
11ah (draft-delcarpio-6lo-wlanah-00).  Also there are some I-Ds (like 
draft-petrescu-ipv6-over-80211p-03.txt) looking for a home.

Other possible ways is to question how would IP work over 802.11

The IEEE efforts for a better WiFi may translate into a need for a 
better IP: more bandwidth 802.11ad, ax (a highly efficient IP?), and 
lower energy ah (an IP over typical LLC?) and operation at a 
yet-uncrowded 60GHz (an expensive IP?).  Not to mention this EUI-128 
identifier which should lead to forgetting the EUI-64-derived /64 
barrier altogether.

Alex

> I remain perpetually astonished that a technology beloved by and used
> by billions (with billions to come) has so few advocates, so few
> working on actual interoperability, so many bad implementations, and
> so little research funding.
>
> the general public has their priorities straight:
>
> https://www.google.se/search?q=image+hierarchy+of+needs+wifi&source=lnms&tbm=isch&sa=X&ved=0ahUKEwi32M36qbjJAhWEqnIKHSseCiMQ_AUIBygB&biw=1135&bih=1072
>
> For those that haven't seen it:
>
> https://www.youtube.com/watch?v=Rb-UnHDw02o
>
> I am happy that a little bit of funding towards merely getting per
> station queuing working looks to arrive next year.
>
> Tackling handoff in any sane way with the current mess, looks harder.
>
> _______________________________________________
> homenet mailing list
> homenet@ietf.org
> https://www.ietf.org/mailman/listinfo/homenet
>