From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-x530.google.com (mail-ed1-x530.google.com [IPv6:2a00:1450:4864:20::530]) (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 C729A3B2A4 for ; Tue, 15 Mar 2022 23:49:50 -0400 (EDT) Received: by mail-ed1-x530.google.com with SMTP id b24so1168475edu.10 for ; Tue, 15 Mar 2022 20:49:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=QzRHaE/en6bnliPwuSV1D5rs5eZ2NnvWkXQMmBXoqSI=; b=Aaz9kQq1GPRzBsxggau6pnA+tb24bZROSRt3l0A4orrq/qptpHaOsF4bbhObqLWIpv Q2rCRoibil7sV45or4C5yRt0C9TkQCBv+f/hKVLG+UqtsBCOEENq/PpTrkV4jkgxP7id i9nLnGyf5+Wx5YCTZcE4EN4/D9chOoBunLNMSk4CZKfNj1ZSuVCInsfXAu807IebKRJc 6AolF0rhtGkEpFrO2ug6jxhfPXTrJ/wDZBgyg+1iPX70JJU+cyFuHmJW2sOkZJ+UIybW YV0rZzpM6NreJQYkLUVmd5PPJNgQ/rOhC1OBjnlcqR72hDQ2uliQnT9OFgNvcLC0LLxU 81PQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=QzRHaE/en6bnliPwuSV1D5rs5eZ2NnvWkXQMmBXoqSI=; b=xg+GPbYiXUv52l8OqhdjTtoVcmy6hD20/K92PNr5443JOL2WH1SBXsoQmnV+pRX62M whVdc94lFBwNW92dbNiWgn52Yw/JswF0VpmPz2cR+n0IG/bZRINoJY+Glc4/AAhwm8WF hUe8YHewUuHvYVhds5Rzv0oxQGernOZezFJupcQfwS0DcaPPwTRWyNGC/pGP0CrU106J Hdv0uJ9BbwYlvZUvVoNQI4hvTDC9oo5jS3bLhBQbGyU9CzXdcdNPao1ARmd1oKSsLRK0 0fZ5/xWmJWAP/7wkgDIbAWYTjNz6GbxyWuHVEPO9Y0fGYG/LA0oDGx9/pCDV4B5iPJRS 44qA== X-Gm-Message-State: AOAM531kfj0k13W/kFoEU4vn/zd+CK8zKhnVCUM2pq4XLBbs+/QXP/BL qpBah5FpvZdB/y/l5r7KbSEvlnRHxX6VZAB93m2F/Dvp X-Google-Smtp-Source: ABdhPJxnA+jlW8+Jpr0ED0k5fSvdnJlo1WBfTxk+Yo7Y/ECk8th8rrDqsQDfcGnKy96YhrXwiIJCVeuI+WxySTpuRmE= X-Received: by 2002:a05:6402:430c:b0:416:7e66:2c06 with SMTP id m12-20020a056402430c00b004167e662c06mr28253221edc.116.1647402589539; Tue, 15 Mar 2022 20:49:49 -0700 (PDT) MIME-Version: 1.0 References: <08c6ab5c-6a9d-e555-671c-5c59cffcd02d@falco.ca> In-Reply-To: From: Dave Taht Date: Tue, 15 Mar 2022 22:49:37 -0500 Message-ID: To: Daniel AJ Sokolov Cc: starlink@lists.bufferbloat.net Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [Starlink] Optimized for Speedtest? X-BeenThere: starlink@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: "Starlink has bufferbloat. Bad." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 16 Mar 2022 03:49:50 -0000 (for the record my d and e keys are not working well right now) On Tue, Mar 15, 2022 at 10:48 PM Dave Taht wrote: > > One of the many unknowns is about how starlink schedules uplink and > downlink "rates" (e.g to some extent the density of encodings). Is it > one or more beam with multiple destinatons on the down? Or ? > > Toke went deep into how wifi ATF works here: > https://blog.tohojo.dk/2016/06/fixing-the-wifi-performance-anomaly-on-ath= 9k.html > > Another big question is how they handle encryption(s), again, how wifi > works from my notebook is here: > https://blog.cerowrt.org/post/crypto_fq_bug/ (with just how hard it > was to get right! I still have 87 blog entries from that era to write > up!) > > I can think of a half dozen different ways they could be modulating > the beams to encapsulate all the data! Wifi had crypto baked in late > (see above) and i would have started with good crypto first in their > case, but "my" solution would have much higher power requirements > (spitting own all data, received by all, decrypted by the receivers > that could find their segments) than what I think they are actually > doing, but without two dishys on the same cell, closely linked in time > via gps pps, and refine analog an digital measurements, can't wager a > guess at the moment. > > On Tue, Mar 15, 2022 at 5:48 PM Dave Taht wrote: > > > > For the historical record, we finally found ways to compensate for the > > wildly variable bandwidth wifi can have in 2014, and mainlined into > > linux in 2016. > > > > https://blog.cerowrt.org/post/real_results/ > > > > Example of ath10k wifi before/after here: > > > > https://forum.openwrt.org/t/aql-and-the-ath10k-is-lovely/59002/ > > > > starlink, on the uplink anyway, seemed straightforward to fix, in > > comparison to wifi. > > > > > > On Tue, Mar 15, 2022 at 5:39 PM Dave Taht wrote: > > > > > > On Tue, Mar 15, 2022 at 5:09 PM Daniel AJ Sokolov w= rote: > > > > > > > > Hello, > > > > > > > > From this list I have learned that Starlink is optimized to shine = in > > > > tests with speedtest.net and similar sites, but that transmission r= ates > > > > drop quickly after about 15 seconds. > > > > > > That is not strictly true. The trend is a low rate for the initial > > > 15s, then a boost, then variable. It happens that speedtest reports > > > the *last* result in the typically 20s it runs, > > > so by that light is starlink is "optimized for speedtest". Much of th= e > > > internet is "optimized for speedtest", tons of services basically blo= w > > > up classic tcp congestion controls at T+21s. > > > > > > Attached are two example flent test runs, a rrul test from one projec= t > > > member's dishy, and a tcp_nup test from anothers. > > > > > > For reference also attached is how a present day WISP 60Ghz radio > > > functions, one which has FQ and AQM, with consistent bandwidth, and > > > only ~5ms latency swings. Ideally the latency on starlink would not g= o > > > over 10ms their baseline ~40ms latency, under these loads. > > > > > > Comparing the later two tests you can see the inversions between > > > bandwidth and latency that come from the fixed length fifos starlink > > > uses at any of the roughly 3 > > > speed settings we currently see. > > > > > > PS - most web pages cannot use more than 25MBit in the 3s they typica= lly take. > > > > > > > How do they do that, technically? > > > > > > Allocate bandwidth? Unknown. Ever 15s seems silly. Not modifying queu= e > > > length and/not using a smarter queuing algo like fq_codel or cake whe= n > > > they do change the bandwidth allocation is the simple flaw in their > > > design I keep hoping they'll fix. > > > > > > > > > > > Is that a result of Bufferbloat? > > > > > > Yes. The rrul test is often illustrative of the problem on how slowly > > > the internet operates during an upload clogging up the queue, or vice > > > versa. Most ISPs do some sort of ack filtering or prioritization to > > > make uploads interfere less with downloads, or use AQM, fq or a > > > combination of both. > > > > > > > Is that a a specific code in the modem > > > > to cheat, like some car manufacturers cheated on emissions tests? > > > > > > I hope not. No, they do have limited capacity, do have to change sats= , > > > do need to allocate bandwidth sanely. AND buffering. > > > > > > > Is > > > > that something done in the satellites who shift capacity from other > > > > users to those users who initiate downloads? Is that done on the ba= ckhaul? > > > > > > Wish we knew. In my ideal world they would supply a statistic that a > > > sch_cake could take and vary the rate/buffering based on that on the > > > home router, or just do it more right > > > in the dishy and head ends with cake + BQL. > > > > > > > > > > > Thank you > > > > Daniel > > > > _______________________________________________ > > > > Starlink mailing list > > > > Starlink@lists.bufferbloat.net > > > > https://lists.bufferbloat.net/listinfo/starlink > > > > > > > > > > > > -- > > > I tried to build a better future, a few times: > > > https://wayforward.archive.org/?site=3Dhttps%3A%2F%2Fwww.icei.org > > > > > > Dave T=C3=A4ht CEO, TekLibre, LLC > > > > > > > > -- > > I tried to build a better future, a few times: > > https://wayforward.archive.org/?site=3Dhttps%3A%2F%2Fwww.icei.org > > > > Dave T=C3=A4ht CEO, TekLibre, LLC > > > > -- > I tried to build a better future, a few times: > https://wayforward.archive.org/?site=3Dhttps%3A%2F%2Fwww.icei.org > > Dave T=C3=A4ht CEO, TekLibre, LLC --=20 I tried to build a better future, a few times: https://wayforward.archive.org/?site=3Dhttps%3A%2F%2Fwww.icei.org Dave T=C3=A4ht CEO, TekLibre, LLC