From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-we0-f171.google.com (mail-we0-f171.google.com [74.125.82.171]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id B8EC0200890 for ; Tue, 13 Mar 2012 18:10:27 -0700 (PDT) Received: by werm1 with SMTP id m1so2053446wer.16 for ; Tue, 13 Mar 2012 18:10:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; bh=cqETjZGlTdXigjst+f/aJoe9BkmqdeBMjf5cbvlxClo=; b=GFSAMySgdfS5WmtNWZRk5qBrA9VovWGn+DVwsQO1mfUGoqtZqKw4+YX0siTecrtraZ UJAXYjYQydjERqFXtDq3CeRN0rO0UIfNlPCjBtkUm3oPnIGLYkpuNEJB85U/TROuZVXD vEfrmAFmvopt9FYAONYbpT7mTcv5Eqr2Hprj/IlfYPAQMxinINgRtTOD9Rdp9Jm6IgmI hxATjKxBzb0DeaakOMbnoXEKN3+EanekfkjPTDX0FicA6udJ+mWPSdp3HsEDXxwaj8Rb +bi6faaKPF1ocnVPAMX814pRZrRlwQbvyVuYKaQTbKyDXM0wUUWbp9j7bPIrrp85/P69 wpkQ== MIME-Version: 1.0 Received: by 10.216.202.99 with SMTP id c77mr367511weo.5.1331687425422; Tue, 13 Mar 2012 18:10:25 -0700 (PDT) Received: by 10.223.151.8 with HTTP; Tue, 13 Mar 2012 18:10:25 -0700 (PDT) In-Reply-To: <20120313230612.GA24800@thyrsus.com> References: <20120313230612.GA24800@thyrsus.com> Date: Tue, 13 Mar 2012 18:10:25 -0700 Message-ID: From: Dave Taht To: esr@thyrsus.com Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: thumbgps-devel@lists.bufferbloat.net Subject: Re: [Thumbgps-devel] Project clarification X-BeenThere: thumbgps-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 14 Mar 2012 01:10:28 -0000 On Tue, Mar 13, 2012 at 4:06 PM, Eric S. Raymond wrote: > Mike Hord : >> Can someone please clarify for me exactly what the aim is, however? I've >> been unable to find a cohesive problem statement anywhere. From what I'v= e >> gathered, the idea seems to be to use the GPS timebase to provide a far >> better gauge of time-of-flight (I'm not a network engineer; I don't know >> what the real term would be) of a packet from one location on the intern= et >> to another than current methods can provide. I LIKE your description! I also agree that things are confusing, this project was stalled out for 9 months before it hit erics blog (after being locked in his basement trying to make anything work for a week), and now this list... A couple notes to tack onto esr's notes - 0) We've been trying to get something better than ntp or gps-without-pps for a while now... the more accurate this can be made, the smaller the error bars for time of flight. Right now the error bars are in the half a diameter of the internet range (170ms) 1) jg and I were involved in olpc and one of my long term other projects has been to finish spreading the internet around the world. Doing that in many places gets hard. I was working on mesh networks, and having small gpses actually on routers on the poles/trees/etc would have helped a lot on finding the devices again. (this is something of project creep, see 3). In the long run (after this project!) I'm thinking something 'smile plug'-like+gps. I note that in that long run perhaps the gps feature will become integral to outdoor wireless, as it has entered at least one product line already: http://www.ubnt.com/rocketmgps 2) Having reliable time on or near boot down there is good (kerberos needs 5 minutes, dnssec an hour, dhcp and routing daemons have time dependencies), particularly as the reason for a boot is usually a power failure that has taken out a sizeable chunk of the network. 3) While cbbd was originally conceived of as a way to fact-check ntp beyond the edge, and be able to take a harder look at the data ntp was filtering out, there seem to be other uses that we're blue-skying about (I mentioned weather stations as one, gps+crypto as another), to try and come up with something more unique. 4) But we circle back to trying to get down to 1ms resolution, or better, on the other side of the network edge, as the core goal. --=20 Dave T=E4ht SKYPE: davetaht US Tel: 1-239-829-5608 http://www.bufferbloat.net