From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.toke.dk (unknown [85.204.121.218]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 65B953B29E; Fri, 24 Jan 2020 04:51:21 -0500 (EST) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=toke.dk; s=20161023; t=1579859479; bh=Jzen/9BX6GzUxn25k7zleXJXeUxhSggMnmLkNqYfBMc=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=YwjdYp7aws/YV229sUA+kXCKD+gIHNo0pvrR3h+LfB8fRiV5/3dquxZlf8G8C7VDr m8w4aGc5LH1h8v1fsxXazU9cizTZBxjqxZNJivAyf588dShyyz8g2Pdi1JlBrn2AIE guD8LRHv3p82cpBmMmtSsMOj02Ga+xDt/lrNRmuQx38PjLDKqtZfvLhwKLXaszqfE5 I1Pq3x+7i8YaSWVsluqvoLzyS2YAQ6hWeocitvTPMTjK5d41xvEhmgsTT9T21ndF4/ 43MgFEDdiKaYBodA37W1a5ZYjqcOZDhWm5e6UVoj0ujuSEipVKqU3ssYMnKlzyllt/ va0XoA5Ww3btw== To: Dave Taht , Sebastian Moeller Cc: ECN-Sane , bloat In-Reply-To: References: <95CC814B-9F95-4C79-BF47-ABB551B50429@gmail.com> <3D7A8E2C-5A8F-4FBB-89B0-9711E46CD560@gmx.de> Date: Fri, 24 Jan 2020 10:51:19 +0100 X-Clacks-Overhead: GNU Terry Pratchett Message-ID: <87zhedgp2g.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Ecn-sane] 2019-12-31 docsis strict priority dual queue patent granted X-BeenThere: ecn-sane@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Discussion of explicit congestion notification's impact on the Internet List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 24 Jan 2020 09:51:21 -0000 Dave Taht writes: > To be deliberately contrarian - (I do try to only pay attention to > this a few days a month) - after also re-reading > https://www.cablelabs.com/technologies/low-latency-docsis and the > associated white papers (yes, 24 hours on a plane can do this to you) > > 1) I've never been able to figure out where the 99 percentile latency > figure so often cited came from. on the upstream which typically runs > well below 20Mbit, a single IW10 burst at 10Mbit is 1.3ms, so I've > generally figured it was either a long term figure, or calculated from > a much higher (100mbit? 1gbit?) downstream rate against some load > that's never been documented. (that I know of, please note that I > don't > read much of the traffic about this stuff) > > 2) There is a lot of valuable looking stuff in the lower level aspects > of the docsis LL standard. I'd noted it when I first read it, but > achieving .9ms baseline a/g latency finally does make it competitive > with fiber with whatever the heck "pgm" is. So far as I knew, the > overlapping grant request and estimator functions documented in the > patent are already present in most cablemodems already, and not really > tied to the ll spec... but that data would be interesting to get out > of the modem itself, somehow. The histogram is made available via a > MIB to the operator. It would be nice if those MIBs were also visible > to the user somehow. > > 3) > > In the docsis-ll white paper and spec it lays out cmts requirements > also. With the cmtses currently exhibiting 500+ms of latency at > 100Mbit loaded, from a mere "solving bufferbloat" perspective - > getting just pie there to work would be *marvelous* - it would be > superior to any of the fiber deployments I know of. dualpi, even if > not configured for l4s ecn support, would be a godsend. The ECO for > cablemodems at least, went out over a year ago. > > some aqm tech becoming common on these head ends would also spur > deployment of aqm (or fq + aqm) tech on fiber also. But I've seen no > info as to what's going into cmtses today. Haven't seen any > announcements... > > I still have no idea what is going to happen on 5G. I have heard about 5G vendors implementing CoDel on their modems. Maybe what will end up happening is that all the promises of "low-latency networking" on 5G will end up being true simply because the vendors finally fix their bloat? ;) -Toke