From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm1-x32d.google.com (mail-wm1-x32d.google.com [IPv6:2a00:1450:4864:20::32d]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id B968B3B29E; Mon, 13 Mar 2023 12:06:29 -0400 (EDT) Received: by mail-wm1-x32d.google.com with SMTP id ay8so3139052wmb.1; Mon, 13 Mar 2023 09:06:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1678723589; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=PRZOaYBfur/Tk4eJleMu4y+ADDrOfViFpoeGl9aUI64=; b=U0TkyRdncWbErIl3TvWdmQMRGroWmr/zvSdhrMqiL8uGaF4HbxkeyTk+gdtxibCRef uQa0vMsoMXEeLE6Cr3KedASDnulmzc1JbtijedOCxumAfXdHOoc7QcHFZOEby2LoJaYg bk9wTy+d5bu36hAD9iQU4dmbjN11cnXmmXj+Y6gNW+U5CfrlhZQieUTqfrObp02mPmS7 qb9Xlyf09nUQMMaHNVDF/3MKm03xdur2otGP6/x9eNP5FSKLrUpH8Ixs/uY6iM5Egrik LGYGzs51de8e2XkQA9iKq1m8i7AhNG/AV42kDlpxtJIMexpPqOx8BIiF2W57gD4s81TJ fvUw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678723589; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=PRZOaYBfur/Tk4eJleMu4y+ADDrOfViFpoeGl9aUI64=; b=wW7eTTo8giWId04FobtyQyX5Kv7AsZ8wcNvzJHCG51G55qb069x+oFlMHVFsR0H/sQ 8nVxxFxsJunoOV6UAzCmUNkrOuQtLZ/5XeaCi+3ML9oGrDdUHwfyGlkavbhUMm4kF2Kx fZJ1BZYfPLhOvYZ+Yr7ezi0yuSEYbdDAsy5MINZ0q/WPbNL9h4+Aw9a6Lc7KGHFI8nHE CZV5erGjTNaz3F0arYXGfz+W6U1RlddWmCJTa1nJAVDG/t6HRVs7WAa5zyqwpNG6LPSI Y9o4Umzv5khbfDmK5DOp2cr0ruU2T8+HuWEN6zAQ5HDsu8vKdwi1gQ+YTJIW5BL+hq0K 2d2g== X-Gm-Message-State: AO0yUKXv/j+ouT8tQ412z6lQmjELKn9DqudiyzoRusisaF77g+ZRPBGE NBQSUvaZBfAjlgqAjbaUIfckg210g55jJD7svuo= X-Google-Smtp-Source: AK7set8khR2jKf9+l7EcsvEdtdvYrv7L0eFecEVPF/NTaRc5bi07rD29eCSTpKRtmGgfhR+8yQFe7L9MtuiQ+T2hyyg= X-Received: by 2002:a05:600c:35cd:b0:3eb:8ac:eeab with SMTP id r13-20020a05600c35cd00b003eb08aceeabmr3301287wmq.0.1678723588635; Mon, 13 Mar 2023 09:06:28 -0700 (PDT) MIME-Version: 1.0 References: <1672786712.106922180@apps.rackspace.com> <77CCAD19-07E0-4F9E-88C1-D207CF7BF376@cable.comcast.com> <83ffc0dad19e3343e49271889369cefc@rjmcmahon.com> <3CD0B9E6-0B2A-4A70-8F53-ED0822DF77A6@gmx.de> In-Reply-To: <3CD0B9E6-0B2A-4A70-8F53-ED0822DF77A6@gmx.de> From: Dave Taht Date: Mon, 13 Mar 2023 09:06:16 -0700 Message-ID: To: Sebastian Moeller Cc: Jeremy Austin , Dave Taht via Starlink , dan , libreqos , Rpm , rjmcmahon , bloat Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [Rpm] [Bloat] [Starlink] [LibreQoS] [EXTERNAL] Re: Researchers Seeking Probe Volunteers in USA X-BeenThere: rpm@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: revolutions per minute - a new metric for measuring responsiveness List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 13 Mar 2023 16:06:29 -0000 On Mon, Mar 13, 2023 at 8:50=E2=80=AFAM Sebastian Moeller via Bloat wrote: > > Hi Jeremy, > > > On Mar 13, 2023, at 16:08, Jeremy Austin wrote: > > > > > > > > On Mon, Mar 13, 2023 at 3:02=E2=80=AFAM Sebastian Moeller via Starlink = wrote: > > Hi Dan, > > > > > > > On Jan 9, 2023, at 20:56, dan via Rpm wro= te: > > > > > > You don't need to generate the traffic on a link to measure how > > > much traffic a link can handle. > > > > [SM] OK, I will bite, how do you measure achievable throughput = without actually generating it? Packet-pair techniques are notoriously impr= ecise and have funny failure modes. > > > > I am also looking forward to the full answer to this question. While on= e can infer when a link is saturated by mapping network topology onto laten= cy sampling, it can have on the order of 30% error, given that there are mu= ltiple causes of increased latency beyond proximal congestion. > > So in the "autorates" a family of automatic tracking/setting meth= ods for a cake shaper that (in friendly competition to each other) we use a= ctive measurements of RTT/OWD increases and there we try to vary our set of= reflectors and then take a vote over a set of reflectors to decide "is it = cake^W congestion", that helps to weed out a few alternative reasons for co= ngestion detection (like distal congestion to individual reflectors). But t= hat dies not answer the tricky question how to estimate capacity without ac= tually creating a sufficient load (and doubly so on variable rate links). > > > > A question I commonly ask network engineers or academics is "How can I = accurately distinguish a constraint in suppl from a reduction in demand?" > > Good question. The autorates can not, but then they do not need t= o as they basically work by upping the shaper limit in correlation with the= offered load until it detects sufficiently increased delay and reduces the= shaper rates. A reduction n demand will lead to a reduction in load and bu= fferbloat... so the shaper is adapted based on the demand, aka "give the us= er as much thoughput as can be done within the users configured delay thres= hold, but not more"... > > If we had a reliable method to "measure how much traffic a link can handl= e." without having to track load and delay that would save us a ton of work= ;) My hope has generally been that a public API to how much bandwidth the ISP can reliabily provide at that moment would arise. There is one for at least one PPOe server, and I thought about trying to define one for dhcp and dhcpv6, but a mere get request to some kind of json that did up/down/link type would be nice. > > Regards > Sebastian > > > > > > -- > > -- > > Jeremy Austin > > Sr. Product Manager > > Preseem | Aterlo Networks > > preseem.com > > > > Book a Call: https://app.hubspot.com/meetings/jeremy548 > > Phone: 1-833-733-7336 x718 > > Email: jeremy@preseem.com > > > > Stay Connected with Newsletters & More: https://preseem.com/stay-connec= ted/ > > _______________________________________________ > Bloat mailing list > Bloat@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/bloat --=20 Come Heckle Mar 6-9 at: https://www.understandinglatency.com/ Dave T=C3=A4ht CEO, TekLibre, LLC