From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.15.19]) (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 B378E3B29E; Mon, 13 Mar 2023 11:50:42 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.de; s=s31663417; t=1678722637; i=moeller0@gmx.de; bh=/7MRCVeSdTbFvkskornSwEkYwWSC3y+KOaB/pbpMazs=; h=X-UI-Sender-Class:Subject:From:In-Reply-To:Date:Cc:References:To; b=PCob/0I49xWR0CFjKZvS7IH7RJCLTUY7Uua3B/ijy326qdO5VfMI48WE/bAHvLz0n Tzo1yGimvKYgj+30CCF6zFE2PDoqe+NtA7hMhmELDgeL3zwHUnWN/2BrnZh01XUL76 i8ZcVinc0Tr5uvtnxofIYIdaObZxtqHZr5eFgPllII/bnch3q9TvaB3W3emfvTSLgc rldORv7TsA00uKAU+QLq10LqViJKzKfyUNrIB7B4mzHDXlN0uxsnwIwtkXYssqYD8F AXmF6sQ6a3L+zrTJQI6nFnQWTmgTDVZFc42a1bB+akj2+8XRLNLSlCMa2cD7GFvsWU xTlmTyfdkbXgQ== X-UI-Sender-Class: 724b4f7f-cbec-4199-ad4e-598c01a50d3a Received: from smtpclient.apple ([134.76.241.253]) by mail.gmx.net (mrgmx005 [212.227.17.190]) with ESMTPSA (Nemesis) id 1M3DJv-1pYB8a1YEf-003Zkt; Mon, 13 Mar 2023 16:50:37 +0100 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3696.120.41.1.2\)) From: Sebastian Moeller In-Reply-To: Date: Mon, 13 Mar 2023 16:50:36 +0100 Cc: dan , Rpm , libreqos , Dave Taht via Starlink , rjmcmahon , bloat Content-Transfer-Encoding: quoted-printable Message-Id: <3CD0B9E6-0B2A-4A70-8F53-ED0822DF77A6@gmx.de> References: <1672786712.106922180@apps.rackspace.com> <77CCAD19-07E0-4F9E-88C1-D207CF7BF376@cable.comcast.com> <83ffc0dad19e3343e49271889369cefc@rjmcmahon.com> To: Jeremy Austin X-Mailer: Apple Mail (2.3696.120.41.1.2) X-Provags-ID: V03:K1:jkywrSj8UC9/LicIG5oyxoP3bDq41FgANd+9CiFuk7g9ciDW3Et Q0u9orrfkppbdBVIPqCe8Ek9IRGX/mjSaYYtnhyKiTuOSuOpkNfzeJsI83XWB8XvnktOReS JkmfQxIv7W3MnY5QTpuIxZkZTJ7NGDdctdYFQSAOk43L4sjSfh1JVj78a0b6+nJOLqM17VU Uh1iSzQurga3deJuM/xlQ== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:ix0z9dpdEYk=;4oAn7LJQEi4qTKEWGK/B14ctMr8 bRAa6gIPIBMAJesmgY8AT+4GfYhV/nwDDQLpU/Za/NY4Vm+9K6ME9ioi+WvspD9h4XAwV6E3J wFJVBzLEJyESCHeDlT2p6FEZwcFp8IxauukqXtl9Sv2iyjlD0rkoqNGIdFKbE+E68vuRpeHoa HaQv7l4G8wO0V1G6HZXmrlcE/S57AOiknUhc8CDmewWAnAyRuigOS/JO/v0W8TcHNvU/ZGPYM d6aNda6GLTjBz7kk04XpIGdztqyhpeWsg4Kpeecg3svIY63588I97rwZNDgTEgA2RJ2dnIdK0 fUCBZrMWtMthmQXi69nvxYzcvFhwuQYBpeKzWT1G6V+06JlS/Pd4iQVRRxwvp+NDFcdoiP7Hd z59ifAQfwMIlHCHJ0BN5H8rnc2J8ej4yVrkt9RbrfAfKIa9DEXXyqKbTH/QjtR/UB3iAJrzqE Q0v3NYha9aktqtrzudRLjKwH5jPVUMfJEJp/uqBYErlLSEVhx/5rYZELB4rNURGwIclCErP6V mK0FQKF0TfVPmn5PJUbcfpHtbhqNI4L6UH2zBqDPj8EAqRdfqJk0L405rPHpHZNFlRyAWKPEF 6ljBTMABJ5MB5dvL29A/3llHmmHiorTsgRf5PMbNe2IOJNAbI2fBYWm9SjtQENBUq8g9SyPLy hyN6aVwsqXGHhxFDRxaPWc9BqrTRDG4K+GhYsSYWT8mEsP8Z1tVOkS9awpc+CBZ2/81PwbJkb e1PI1B9kBlb5Sas3PqUVRmn3l7+hdFQx0kPH9bnsqa/jx5mRDvoHO8YfDz9z+YPMffppvxEgy iew/LVXAeVCOPhD+ZKtMa7pw72epaawemVrX0O7qu5LUGVyQHtpWU/ktanzV3xAPN/0hYrjam 8OeG9N60RO2KeDzJhcaR8KmEcL5/RSXQNXzxraEdcqZynNx8j4s5foISJucS6LkxK69Gg5wFq w1mwvxn6FNwCcmgp+/eTlzxd9Tc= Subject: Re: [Bloat] [Starlink] [Rpm] [LibreQoS] [EXTERNAL] Re: Researchers Seeking Probe Volunteers in USA 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: Mon, 13 Mar 2023 15:50:43 -0000 Hi Jeremy, > On Mar 13, 2023, at 16:08, Jeremy Austin wrote: >=20 >=20 >=20 > On Mon, Mar 13, 2023 at 3:02=E2=80=AFAM Sebastian Moeller via Starlink = wrote: > Hi Dan, >=20 >=20 > > On Jan 9, 2023, at 20:56, dan via Rpm = wrote: > > > > You don't need to generate the traffic on a link to measure how > > much traffic a link can handle. >=20 > [SM] OK, I will bite, how do you measure achievable throughput = without actually generating it? Packet-pair techniques are notoriously = imprecise and have funny failure modes. >=20 > I am also looking forward to the full answer to this question. While = one can infer when a link is saturated by mapping network topology onto = latency sampling, it can have on the order of 30% error, given that = there are multiple causes of increased latency beyond proximal = congestion. So in the "autorates" a family of automatic tracking/setting = methods for a cake shaper that (in friendly competition to each other) = we use active 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 congestion detection (like distal congestion to = individual reflectors). But that dies not answer the tricky question how = to estimate capacity without actually 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 = to 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 bufferbloat... so the shaper is adapted based on the demand, = aka "give the user as much thoughput as can be done within the users = configured delay threshold, but not more"... If we had a reliable method to "measure how much traffic a link can = handle." without having to track load and delay that would save us a ton = of work ;) Regards Sebastian >=20 > --=20 > -- > Jeremy Austin > Sr. Product Manager > Preseem | Aterlo Networks > preseem.com >=20 > Book a Call: https://app.hubspot.com/meetings/jeremy548 > Phone: 1-833-733-7336 x718 > Email: jeremy@preseem.com >=20 > Stay Connected with Newsletters & More: = https://preseem.com/stay-connected/