From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-il1-x12c.google.com (mail-il1-x12c.google.com [IPv6:2607:f8b0:4864:20::12c]) (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 086D63CB35 for ; Fri, 9 Jul 2021 14:45:17 -0400 (EDT) Received: by mail-il1-x12c.google.com with SMTP id e13so11423331ilc.1 for ; Fri, 09 Jul 2021 11:45:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nathan.io; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=4OjdFqBjwBR71TqUNmOgpqMt2h67vqsisZgQgGAC5iQ=; b=qbUExWmaIpAG4zTdMnYq+7TAsf1s4I861VnfdN1AFSX819d4VEorNcxgmWBso0iZF1 CfU31IIR5NqgfhOKLSy89iQQyTy/3ecfGrua9UKi7qDUT3J2znXZznYRKiZ71lKvBrv5 Ew/qUjAqiWBO1WbFu8A9Bpd6aocpdE/vS1y0lPk5F1sc/UZImAfRvLNClVcsfIVavOd7 hwnBlVXMhlMfW9CXc9wUwiDX5RQK5ieNqqjMGU7XxInZRiV10sEKWTa7obyNfcNB4nuO 0xiuDE2PwhT3a+Yyb/2s8uSVYaVmIBM+qqQYWyjIdm1w8V9vQ+Gu1tJD3vHPT7xL3OIy 2RgQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=4OjdFqBjwBR71TqUNmOgpqMt2h67vqsisZgQgGAC5iQ=; b=n1bqMvxwME3kRFQqkYyparrvaGACA0fthlGYGWIZU0W7PBl/ACo209tl12PE4PczNL XRwZ2r+GbamWGrUKJMaw29+nXzCHS7KIuMhuYcaERt0vdKi6HybEya5JGKR7fdJpnkPP ayo0ih7rkHW/ZALqzGyNDzK4SC4oAfghhQhDqYCTW4V3/dYGxcYj5EaFKsh+9TIB/z4t LG6YoxyBpvLEgGDSlcwQWMSuZZDYk+nZsrZu2YjuDOY3PgwMB0UjgzJb3NRxtIrJDtkP CeYH0KZ9E/yW9FaNx79tmhA3MgSaCneaUneyrj4KFY1GB0VEgdG9t4pazgT2eFIah41H piMA== X-Gm-Message-State: AOAM533xWfPD5LwPscpi51XUKYG1Zf+0l8znguTElnVCGS2YOXVHCAWA jHcI90qXeNy8WtdxZN8Y+sxQ5o/BQZX2Iov19Cfeow== X-Google-Smtp-Source: ABdhPJxBRzPlRBACzGenQVOnhKezP81EAae1Ruy/V47RH3L264kI7coM5n+FFBoPHO5Tj7Nvf2Q0oU8dclo/H2wqFW8= X-Received: by 2002:a92:c888:: with SMTP id w8mr10644792ilo.140.1625856317059; Fri, 09 Jul 2021 11:45:17 -0700 (PDT) MIME-Version: 1.0 References: <1625856001.74681750@apps.rackspace.com> In-Reply-To: <1625856001.74681750@apps.rackspace.com> From: Nathan Owens Date: Fri, 9 Jul 2021 11:45:06 -0700 Message-ID: To: "David P. Reed" Cc: starlink@lists.bufferbloat.net Content-Type: multipart/alternative; boundary="0000000000003c055005c6b52c85" Subject: Re: [Starlink] Starlink and bufferbloat status? 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: Fri, 09 Jul 2021 18:45:18 -0000 --0000000000003c055005c6b52c85 Content-Type: text/plain; charset="UTF-8" I haven't done detailed testing, but anecdotally, there haven't been any changes I've noticed. A few times, it's seemed worse, with latency increasing to 700-900ms for several seconds after starting an upload, before returning to ~30-150ms. On Fri, Jul 9, 2021 at 11:40 AM David P. Reed wrote: > Early measurements of performance of Starlink have shown significant > bufferbloat, as Dave Taht has shown. > > > > But... Starlink is a moving target. The bufferbloat isn't a hardware > issue, it should be completely manageable, starting by simple firmware > changes inside the Starlink system itself. For example, implementing > fq_codel so that bottleneck links just drop packets according to the Best > Practices RFC, > > > > So I'm hoping this has improved since Dave's measurements. How much has it > improved? What's the current maximum packet latency under full load, Ive > heard anecdotally that a friend of a friend gets 84 msec. *ping times under > full load*, but he wasn't using flent or some other measurement tool of > good quality that gives a true number. > > > > 84 msec is not great - it's marginal for Zoom quality experience (you want > latencies significantly less than 100 msec. as a rule of thumb for > teleconferencing quality). But it is better than Dave's measurements showed. > > > > Now Musk bragged that his network was "low latency" unlike other high > speed services, which means low end-to-end latency. That got him > permission from the FCC to operate Starlink at all. His number was, I > think, < 5 msec. 84 is a lot more than 5. (I didn't believe 5, because he > probably meant just the time from the ground station to the terminal > through the satellite. But I regularly get 17 msec. between California and > Massachusetts over the public Internet) > > > > So 84 might be the current status. That would mean that someone at > Srarlink might be paying some attention, but it is a long way from what > Musk implied. > > > > > > PS: I forget the number of the RFC, but the number of packets queued on an > egress link should be chosen by taking the hardware bottleneck throughput > of any path, combined with an end-to-end Internet underlying delay of about > 10 msec. to account for hops between source and destination. Lets say > Starlink allocates 50 Mb/sec to each customer, packets are limited to > 10,000 bits (1500 * 8), so the outbound queues should be limited to about > 0.01 * 50,000,000 / 10,000, which comes out to about 250 packets from each > terminal of buffering, total, in the path from terminal to public Internet, > assuming the connection to the public Internet is not a problem. > > > > > _______________________________________________ > Starlink mailing list > Starlink@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/starlink > --0000000000003c055005c6b52c85 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
I haven't done detailed testing, but anecdotally, ther= e haven't been any changes I've noticed. A few times, it's seem= ed worse, with latency increasing to 700-900ms for several seconds after st= arting an upload, before returning to ~30-150ms.

On Fri, Jul 9, 2021 = at 11:40 AM David P. Reed <dpreed= @deepplum.com> wrote:

Early measurements of performance of= Starlink have shown significant bufferbloat, as Dave Taht has shown.

=C2=A0=

But...= =C2=A0 Starlink is a moving target. The bufferbloat isn't a hardware is= sue, it should be completely manageable, starting by simple firmware change= s inside the Starlink system itself. For example, implementing fq_codel so = that bottleneck links just drop packets according to the Best Practices RFC= ,

=C2=A0=

So I&#= 39;m hoping this has improved since Dave's measurements. How much has i= t improved? What's the current maximum packet latency under full load,= =C2=A0 Ive heard anecdotally that a friend of a friend gets 84 msec. *ping = times under full load*, but he wasn't using flent or some other measure= ment tool of good quality that gives a true number.

=C2=A0=

84 mse= c is not great - it's marginal for Zoom quality experience (you want la= tencies significantly less than 100 msec. as a rule of thumb for teleconfer= encing quality). But it is better than Dave's measurements showed.

=C2=A0=

Now Mu= sk bragged that his network was "low latency" unlike other high s= peed services, which means low end-to-end latency.=C2=A0 That got him permi= ssion from the FCC to operate Starlink at all. His number was, I think, <= ; 5 msec. 84 is a lot more than 5. (I didn't believe 5, because he prob= ably meant just the time from the ground station to the terminal through th= e satellite. But I regularly get 17 msec. between California and Massachuse= tts over the public Internet)

=C2=A0=

So 84 = might be the current status. That would mean that someone at Srarlink might= be paying some attention, but it is a long way from what Musk implied.

=C2=A0=

=C2=A0=

PS: I = forget the number of the RFC, but the number of packets queued on an egress= link should be chosen by taking the hardware bottleneck throughput of any = path, combined with an end-to-end Internet underlying delay of about 10 mse= c. to account for hops between source and destination. Lets say Starlink al= locates 50 Mb/sec to each customer, packets are limited to 10,000 bits (150= 0 * 8), so the outbound queues should be limited to about 0.01 * 50,000,000= / 10,000, which comes out to about 250 packets from each terminal of buffe= ring, total, in the path from terminal to public Internet, assuming the con= nection to the public Internet is not a problem.

=C2=A0=

=C2=A0=

_______________________________________________
Starlink mailing list
Starlin= k@lists.bufferbloat.net
https://lists.bufferbloat.net/listinfo/starlink
--0000000000003c055005c6b52c85--