From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.15.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id DE8C33B29D for ; Sat, 1 Feb 2025 09:33:53 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmx.de; s=s31663417; t=1738420430; x=1739025230; i=moeller0@gmx.de; bh=c6yu64P0j8UodxDnnnkoK3/Vf3ONiekxBWXivrg1Z00=; h=X-UI-Sender-Class:Content-Type:Mime-Version:Subject:From: In-Reply-To:Date:Cc:Content-Transfer-Encoding:Message-Id: References:To:cc:content-transfer-encoding:content-type:date:from: message-id:mime-version:reply-to:subject:to; b=gEBse1pt4f24vknJFcmWyyR2oEku953aSCQ9hk/0XuCP4bvHu4KasrY0lo08SNw3 mNhwi/VN/fpQohznwaiMZPFPxTp7Bo0QInZuZ9L042paHEhmraW/0xUrKV7ARJvc3 /0CPSKs4nmK6U5/6UCQVDp9ksU03iIMMVLOQ5jjREYXNy8ET8dj0GLsytRc+u0hd/ FV7xRgbD3NNNuJKvfKluJL8bRChVG53KOZmuS/qZdkhs3BDCW+iQ9DmNn3Ruki80t 4gxTjz+JGCrzlEcTAhJyrKP5JA/xJrZtYEUE+ni0aJKt3PQ84sNQv12T8d7iC71UQ YANXKH0PokMXUtCv5A== X-UI-Sender-Class: 724b4f7f-cbec-4199-ad4e-598c01a50d3a Received: from smtpclient.apple ([95.112.41.68]) by mail.gmx.net (mrgmx005 [212.227.17.190]) with ESMTPSA (Nemesis) id 1MTRR0-1u1Nas2zQy-00Q6Tw; Sat, 01 Feb 2025 15:33:50 +0100 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3776.700.51.11.1\)) From: Sebastian Moeller In-Reply-To: Date: Sat, 1 Feb 2025 15:33:40 +0100 Cc: David Collier-Brown , bloat@lists.bufferbloat.net Content-Transfer-Encoding: quoted-printable Message-Id: <9A110AF4-E976-4228-9FA6-92C5C99F611A@gmx.de> References: <48F77C27-0E57-4F96-9BD8-238CC93342F8@gmail.com> To: =?utf-8?Q?Dave_T=C3=A4ht?= X-Mailer: Apple Mail (2.3776.700.51.11.1) X-Provags-ID: V03:K1:Ewm5FSWgUp6MTNUWaDyPIJny2SKWhKVfAIB0t6cM+A5Eb0CiFgh Im62C8kibgkX8jdSWpOLKxHOu3bK63vr1d+NdBSUqn+5R/CLxQspHZkc/ZdYAdsudc9b7Pj s9sA+VcM4D2ZcUNms4LPXmmGxAut3CEwVouTK1aLaKd8YGC5T1CGGEkU17UrbZqhHbto4JW 1PtirWTZ9ctEkmP8N+VuQ== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:2Rw1IoGgivY=;4NgJILA0qMzTGKZ4LXL+UG+LtRn 3pJK8E+TyD1NGe1MJfx0zPVXNHcwMQ9wS9ZMasG0n797XBU/6hhfooNH55bFr28dpeL1N9lD2 gSyqUGVG1Pq8tKEwSlJ+GSkJvdwd73+rrcywbRE+EctHjUC454VW8j9zDMUyGgwzQ8V7k6OZ7 gc3A0731VxXhmf0Ae9El74PzLkrKMwtSPKP5Sn4GMnrqZcydbOPUtJdn3/0dVTn9ekuQudw5R M7QNxuiEB8qbbDQv9yQJFO4lKLjHZRwmG2cufAPlfT1c/qd+y75f4JlaEosXhg9JlqS4xcpTE V2PkCfTFYB8QfsCv6ONO6E/BbaZBy7y9ZGZ1r4ZMa99N4MZ3C99+txevU/JZnrDR0M9p4AV9v nBUXkaa6pqmD1GrzAn2ViWPAaQ/RZfxUclrjl0K9ClIvTpFDzrPix99HLl9UDrjH9AFKdrLnk H9t3bYkfRd/1x8FDZSGKaejN2WjrsyYJ19eYbP9OAL/VsIJZjDfadOcGAOqFzXQT/6eUA4vHU ozmcTpf4XGcTF6vV63RDC8TSOERQbhGjxDYw4bBVd58sOEpiGvAko3L22c5oj1EPzZi4kEi7b OLmk7iUDy2AjtSWLswpuW4kupBVEzAxqLwE8DOhHCXOLh6TywvMGG70U/RATjy23+TU3hsUgM akRW4uzP9Y+AZ2Lm3r4zs1yjQuqEkpy4SLgoZDak6xMjPyq0973NVg1t1EU7oNjM27RroTkWA MJJQ3/tLNOPzfzdjjohOUGS3+SFD6gRN56Tg3QlqPAcDn8zW31FytTTwfifAHHbzDeExWhh8l TEaoW8af8+znoKwKHJPqfM0nVuVU6O8IeJwBlHDRKjyioS+eYV5VrSBZaH9qZ03IYj94dTHZH nzrPjTHFuLx/I4gTwsMloIue6j68xQfPphASmB9fo6pheksiQKbRWgQBop9juIlaN7qq96wRU Z4JU98rllYqFBaC/r54GCJstlOIRnB11mAxcPZJtF7HERj2XvIropGXx70OC1iQcM7IA7XitC ilovx3dp/NLmppaoZeWE+94/fbgTGdLOx7tAb/kgpypIMegUSZwaTg8ddUmN3LpIFbcZhzKWX uldRQDLYROLzMULKaQ1uvdENBWTIKsPF9rqyCbHkKvKQDDLfC7R0BrCpRlcahLESmheVr3jm0 gJyj7GQ51UYqB7aV7pwseNec7lvn+qZ/3gOQUv8rGYrGJE4Bqy4SjptzjI5tjyxSEPf+bEtUg ek1UfsmCHxwlBnWFDqarRNf6uujG0Io9mjhP88MJr9jwL66+o/6KZ+7P0+fJd4Vh7gA+inEPq Q3Ld1xF+hOh+zOmE56q/qM4CVTvbhrhz9KjYovm3Df7Zw8= Subject: Re: [Bloat] Comcast & L4S X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 01 Feb 2025 14:33:54 -0000 > On 1. Feb 2025, at 01:49, Dave Taht via Bloat = wrote: >=20 > = https://www.lightreading.com/cable-technology/comcast-wields-low-latency-a= s-broadband-differentiator And... the press invariably gets it wrong: "Notable is Comcast's use of the Internet Engineering Task Force's Low = Latency Low Loss Scalable Throughput (L4S) standards, which are used to = process and support latency-sensitive traffic. LLD, which is part of the = Low Latency DOCSIS specs, works by separating small, delay-sensitive, = non-queue-building traffic (such as key clicks for an online game) from = the primary (and much heavier) queue-building traffic that, for example, = might carry a video stream or a large file upload or download." As far as I can tell what LLD does is put both ECT(1) and NQB marked = traffic into the same and single L-queue of its conditional priority = scheduler (cable labs terminology), so if a video stream uses ECT(1) = (essentially cloud gaming sends video streams) LLD will NOT separating = it from NQB-marked gaming traffic. Regards Sebastian >=20 >=20 > On Fri, Jan 31, 2025 at 4:40=E2=80=AFPM David Collier-Brown via Bloat > wrote: >>=20 >> What Comcast/L4S is doing was once called, by a Polish colleague, >> "Peeing in the soup, so it smells more like me." >>=20 >> --dave >>=20 >> On 1/31/25 18:57, Dave Taht via Bloat wrote: >>> Here are the positives: >>>=20 >>> For the first time, a major ISP has deployed the PIE AQM on all >>> traffic. Before now Comcast was only doing that on the upstream. >>> That=C2=B4s 99.99% of all current comcast traffic getting an AQM on = it. WIN. >>>=20 >>> The L4S side being enabled will also result in some applications >>> actually trying to use it for cloud gaming. There is a partnership >>> with valve, >>> meta, and apple, that implies that we will perhaps see some VR and = AR >>> applications trying to use it. I look forward to a killer app. >>>=20 >>> Negatives include explicit marking and potential DOS vectors as = often >>> discussed. I do feel that in order to keep up with the jonesies, >>> we will have to add optional l4s marking to CAKE, which should >>> outperform pie (mark-head), I just wish I knew what the right >>> level was - at 100Mbit it seemed at 2ms was best. We also need to >>> remove classic RFC3168 style marking and drop instead when the L4S = bit >>> is present - across the entire linux and BSD ecosystem. >>>=20 >>> There was an abortive attempt last year to get dualpi, accecn, and >>> prague into mainstream linux, but it stumbled over GSO handing, and >>> has not been resubmitted. ACCECN seems to be making some progress. >>> This makes it really hard to fool with this stuff. >>>=20 >>>=20 >>>=20 >>>=20 >>>=20 >>>=20 >>>=20 >>>=20 >>> On Fri, Jan 31, 2025 at 5:27=E2=80=AFAM Sebastian Moeller via Bloat >>> wrote: >>>> Hi Rich, >>>>=20 >>>>=20 >>>>> On 31. Jan 2025, at 14:20, Rich Brown via Bloat = wrote: >>>>>=20 >>>>> Google Alerts sent me this: = https://www.webpronews.com/comcasts-latency-leap-a-game-changer-in-network= -performance/ >>>>>=20 >>>>> Key quote: "Compatibility and Ecosystem: For L4S to have a = significant impact, it requires an ecosystem where both the network = infrastructure and the end-user devices support the standard..." >>>>>=20 >>>>> Can anyone spell "boil the ocean"? :-) >>>>>=20 >>>>> Or am I missing someting? >>>> Well, the whole safety mechanisms in L4$ are laughably = inadequate... this "design" essentially exposes a priority scheduler* = without meaningful admission control to the open internet. This is so = optimistically naive that it almost is funny again. I wish all the = effort and hard work to make L4$ happen, would have been put in a = reasonable design... but at least I learned one of the IETF's failure = modes, and that is at least something valuable ;) >>>>=20 >>>>=20 >>>> *) Just because something is not a strict preempting priority = scheduler does not make it a good idea to expose it blindly... a = conditional priority scheduler with e.g. L4$' weight share of 10:1 = already can do a lot of harm. >>>>=20 >>>>=20 >>>>>=20 >>>>> _______________________________________________ >>>>> Bloat mailing list >>>>> Bloat@lists.bufferbloat.net >>>>> https://lists.bufferbloat.net/listinfo/bloat >>>> _______________________________________________ >>>> Bloat mailing list >>>> Bloat@lists.bufferbloat.net >>>> https://lists.bufferbloat.net/listinfo/bloat >>>=20 >>>=20 >> -- >> David Collier-Brown, | Always do right. This will gratify >> System Programmer and Author | some people and astonish the rest >> davecb@spamcop.net | -- Mark Twain >>=20 >> _______________________________________________ >> Bloat mailing list >> Bloat@lists.bufferbloat.net >> https://lists.bufferbloat.net/listinfo/bloat >=20 >=20 >=20 > --=20 > Dave T=C3=A4ht CSO, LibreQos > _______________________________________________ > Bloat mailing list > Bloat@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/bloat