From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: mail.toke.dk; spf=pass smtp.mailfrom=; dkim=fail; arc=none (Message is not ARC signed); dmarc=fail (Used From Domain Record) header.from=uvic.ca policy.dmarc=none Received: from mail-yx1-f47.google.com (mail-yx1-f47.google.com [74.125.224.47]) by mail.toke.dk (Postfix) with ESMTPS id F0E68938BDB for ; Sun, 09 Nov 2025 06:08:54 +0100 (CET) Received: by mail-yx1-f47.google.com with SMTP id 956f58d0204a3-640d790d444so463894d50.0 for ; Sat, 08 Nov 2025 21:08:54 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1762664933; x=1763269733; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=GRCEo/o8eyZJwUZTDy52s7CjtUDrBCuJfY4VET1MZnc=; b=V4jiD7OshIFMMJuJZUAts43u4mPwP6P3BObDQxUJ3VfLEYTi1587SxeIzC6YjoyVpf RsQZXW1kkqmtxAm904EYV+NM7+A0tm2Ir+fW70M4zb4L0x6ys/751FJZQdX/x9H51NWG 2C0QO+RLnp1XxASs56vHGhqLuPYFSol/N4CYMZkrQWPtuMMgvsZSzOn5FEttTaKAUHhf hdY+4WmemEPmwVkuOOju8jJSGa88uTUHY5DnLk/MGSMOiqKmzA56n+jq+v+NiXc5GQwB pAzPhE2yklPEQ/AAX4buFgdJJUxQpcf1rCvkVHeBGjjgSNMtfXdi4URBeeaVRH6BUjgp uvsg== X-Gm-Message-State: AOJu0YzObRukM5suEYagzwjzi3ov+3kkBv7txfkT+1T0gFZIBTK0YfX3 D1TSU8YLrEog2/1cCtE1Z3oknvM/vZ6XslADAs2PjdhBqSqrchVEBD28FmZ1gt8ruTl+rxGkAj0 /Pg5c1SSPU2b61fFGjCkoLCMVxJ5YgYJaaA== X-Gm-Gg: ASbGncvdecIsAc1jPabLBozhThPVQElb9PBZ06ypCH6AG0DpBMEMtXMx1TYLFv6krvP CmEx0qIEtSrrwzUhfuHnxkQXjEPHjOZtBMC6TMOAWoxymWy1Jlfi9YZod2OLoppHA4Q9zdNl+1d OmwkTXVl5YrDZwwe3DGGCq31D9SwlMRESlyqKCbhP5bCKGmvvwrECwAc2xmeghnsSbDGUW9dQMC iAVig3C0nGvwiLmxYOqWZwdHZzXOCYwMUeXjPiJ5Q66xRP3ma44Y4riZWB+mgT+QyeSFc8= X-Google-Smtp-Source: AGHT+IEjKvOqZlxwBgHE6KUrJYrGa4edK9CidI/sXPEPlxgglw1wLtGDaD4sYoAGgy1ukIzbzqLYu0ke7k0RXC6yvMw= X-Received: by 2002:a05:690e:4301:b0:63e:33a7:cdd7 with SMTP id 956f58d0204a3-640d453aa7cmr2997241d50.20.1762664932939; Sat, 08 Nov 2025 21:08:52 -0800 (PST) MIME-Version: 1.0 References: <176254173597.1347.15997824594759319437@gauss> In-Reply-To: From: J Pan Date: Sat, 8 Nov 2025 21:08:42 -0800 X-Gm-Features: AWmQ_bnlA8mQzGS1ZW_C7wGb79STDNQK5gYKjO1UAL7LFeQM2M1IbrbppYmfCkU Message-ID: To: Ulrich Speidel Cc: starlink@lists.bufferbloat.net Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Message-ID-Hash: GSQDTNDMWMNCI6GRDPLSJ55M3NLJN63Y X-Message-ID-Hash: GSQDTNDMWMNCI6GRDPLSJ55M3NLJN63Y X-MailFrom: panatuvicdotca@gmail.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; loop; banned-address; emergency; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.10 Precedence: list Subject: [Starlink] Re: [LibreQoS] Re: Keynote: QoE/QoS - Bandwidth Is List-Id: "Starlink has bufferbloat. Bad." Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: starlink can use bicast to reduce handover loss, especially for the downlink to the user terminal, but there are still handover delay spike and packet loss, especially for the uplink as well -- J Pan, UVic CSc, ECS566, 250-472-5796 (NO VM), Pan@UVic.CA, Web.UVic.CA/~pa= n On Sat, Nov 8, 2025 at 5:04=E2=80=AFPM Ulrich Speidel via Starlink wrote: > > Starlink is a bit unusual in terms of its packet loss mechanism. > > In "normal" networks, we have damaged packets (low SNR or interference > leading to symbol errors in the modulation that then translate into bit > errors and failing checksums), queue drops as part of the normal > congestion control behaviour, and - not sure how much of a problem this > still is these days - receive window overflows. > > In the case of Starlink and handovers, there appears to be an uplink > queue for uplink to each satellite on the gateway side of things. > Suppose your dishy talks to sat A first and then gets handed over to sat > B. Up until handover time, packets heading to your dishy get sent to the > queue for sat A, thereafter to the queue for sat B. These queues appear > to be different and - with different packets and different volume in > them - seem to lead to situations when a packet addressed to you that's > been enqueued for A hasn't reached the front of the queue by handover > time to B. As A now no longer talks to you, this packet is now on a road > to nowhere. > > Of course, this loss only ever happens at handover time. No such thing > as a uniform distribution here. Moreover, it's NOT a loss that should be > interpreted as a congestion control signal to a TCP sender (or whatever > other protocol is trying to congestion control itself, e.g., some QUIC > implementation or somesuch). > > On the latency vs. bandwidth debate: To me, this seems a bit like > arguing whether width or height are more important for area. Both > matter, and both are equally badly understood by marketing folk. > > If your video needs to stream X Mb/s to the viewer, then the channel > between the sender and receiver needs B > X Mb/s of available and > accessible bandwidth. That's why bandwidth matters. Basta. > > The "accessible" part of the bandwidth is where the latency comes in. > Remember the goal is to hit bandwidth-delay product on the lowest > bandwidth link along the forwarding chain of your packets, i.e., to make > sure you have that bit of pipe filled. It's a lofty goal because > whatever you do in terms of increasing or decreasing your sending rate > only has an effect some time later, by which time the conditions you're > trying to respond to may have changed. Your picture of the current > conditions is always outdated (and more outdated the longer the > latency), and just to add insult to injury, the conditions (available > bandwidth, RTT) can also change without your control input. That change > is among others driven by algorithms that are possibly trying to fill a > different pipe, or has at the very least a different (time-shifted) view > of the conditions at the pipe you're trying to fill. This is a > fundamental control problem, not a matter of BBR over BIC or Reno or > Vegas or whatever you've tried on ns2. > > There are things that make this control problem a little easier: lower > latency obviously, but also exclusive links (or at least fewer competing > flows if you can't get exclusivity), fewer bandwidth bottlenecks along > your hops and bottlenecks that are more predictable, i.e., where the > input queues get processed at a constant processing rate. This is why > last mile fibre and Ethernet in your home are so nice (just because you > have your own WiFi router doesn't mean you have the channel to > yourself). It's also why CDNs are so popular: They combine low latency > with less competition for bandwidth and fewer hops. > > Starlink's challenge is that their bandwidth per cell is limited. Not > quite to the point where it's a problem everywhere, but certainly to the > point where it's becoming a problem in some places. If you're being > asked to pay a congestion surcharge when you sign up, you're in one of > those places. Moving to fq_codel and bringing down the latency has made > more of that bandwidth accessible, but again there's a limit to what you > can do there - it's not like reducing latency increases total bandwidth. > > On 9/11/2025 8:57 am, J Pan via Starlink wrote: > > if there are no obstructions, starlink nowadays can achieve 1% packet > > loss, often 0.1%, mostly due to satellite handover, so for the netflix > > open connect appliances inside starlink pop, they can do some > > starlink-specific optimization to mask away the handover for starlink > > users, e.g., https://oac.uvic.ca/starlink/wp-content/uploads/sites/8876= /2024/09/leonet24-victor.pdf > > -- > > J Pan, UVic CSc, ECS566, 250-472-5796 (NO VM), Pan@UVic.CA, Web.UVic.CA= /~pan > > > > On Sat, Nov 8, 2025 at 11:12=E2=80=AFAM David Fern=C3=A1ndez wrote: > >> "making the link layer more reliable is "the way"", indeed. In the wir= eless data link design projects I have participated, it has always been the= requirement to have packet loss rate (PLR) at IP layer due to physical lay= er errors uniformly distributed and not higher than 0.1%, for TCP, while fo= r wireless links carrying only VoIP, using RTP and G.729 codec, up to 1% PL= R is acceptable. > >> > >> Then, I have seen that Starlink routinely exceeds 1% PLR, reaching up = to 6% or more even, but TCP works anyway, somehow. It may be that CUBIC and= BBR are more robust to higher packet loss rates due to error than Reno. > >> > >> "now physical, link and network layer have more info for > >> the transport layer to make the right decision", but do they? I mean, = how is the transport layer getting info nowadays about the path characteris= tics in terms of bandwidth, latency and packet losses from the layers below= or info like the one you mentioned about Starlink handovers? I still have = not seen this happening, have you? > >> > >> Regards, > >> > >> David > >> > >> On Sat, 8 Nov 2025, 22:30 J Pan, wrote: > >>> yes, end-to-end congestion control was an add-on to tcp flow and erro= r > >>> control, and at that time, packet loss was the only reliable > >>> congestion signal without router collaboration, and the legacy stays= . > >>> from the experience of tuning tcp on cellular networks, making the > >>> link layer more reliable is "the way", at the cost of more buffers an= d > >>> latency. but now physical, link and network layer have more info for > >>> the transport layer to make the right decision, e.g., starlink > >>> handovers at 12th, 27th, 42nd and 57th second of every minute with > >>> delay spike and losses > >>> -- > >>> J Pan, UVic CSc, ECS566, 250-472-5796 (NO VM), Pan@UVic.CA, Web.UVic.= CA/~pan > >>> > >>> On Fri, Nov 7, 2025 at 2:51=E2=80=AFPM David Fern=C3=A1ndez via Starl= ink > >>> wrote: > >>>> Thanks for sharing this Frank. > >>>> > >>>> In slide 3, I think that another effect not to be missed is packet l= osses > >>>> due to errors, which could be analogous to pipe leaks. Sometimes, it > >>>> happens that they are not negligible, in some cases with wireless li= nks, > >>>> mainly, but it could happen too in DSL. I remember that I had a DSL = line in > >>>> which the router had the option to disable interleaving, warning tha= t you > >>>> could get more errors, bad for watching video, they were saying, but > >>>> reduced latency (good for videogames). When packet losses due to err= ors are > >>>> misinterpreted as congestion by the transport protocols, the result = is also > >>>> a band quality of experience. > >>>> > >>>> Regards, > >>>> > >>>> David > >>>> > >>>> Date: Fri, 7 Nov 2025 11:53:44 +0100 > >>>>> From: Frantisek Borsik > >>>>> Subject: [Starlink] Re: [LibreQoS] Re: Keynote: QoE/QoS - Bandwidth= Is > >>>>> A Lie! at WISPAPALOOZA 2025 (October 16) > >>>>> To: Cake List , bloat > >>>>> , codel@lists.bufferbl= oat.net, > >>>>> Jeremy Austin via Rpm , libreqo= s > >>>>> , Dave Taht via Starlink > >>>>> , l4s-discuss@ietf.org > >>>>> Message-ID: > >>>>> >>>>> uhiQPd3KOg@mail.gmail.com> > >>>>> Content-Type: text/plain; charset=3D"UTF-8" > >>>>> > >>>>> Hello to all, > >>>>> > >>>>> Recording of our QoE/QoS panel discussion is out! It was really gre= at and > >>>>> believe you will like it: > >>>>> > >>>>> https://www.youtube.com/watch?v=3DT1VET0VYQ6c > >>>>> > >>>>> We have touch bandwidth, L4S, Starlink and more. > >>>>> > >>>>> Here are the slides with additional reading: > >>>>> > >>>>> https://docs.google.com/presentation/d/1ML0I3Av3DCtQDiP8Djr_YGH2r4-= UDZP25VEk-xyJcZE/edit?slide=3Did.p#slide=3Did.p > >>>>> > >>>>> We hope to continue this conversation into more practical, demo-lik= e > >>>>> environment of sort, that we can see at IETF Hackathon and used to = see in > >>>>> the early WISPA event days, with Animal Farm. > >>>>> > >>>>> > >>>>> All the best, > >>>>> > >>>>> Frank > >>>>> > >>>>> Frantisek (Frank) Borsik > >>>>> > >>>>> > >>>>> *In loving memory of Dave T=C3=A4ht: *1965-2025 > >>>>> > >>>>> https://libreqos.io/2025/04/01/in-loving-memory-of-dave/ > >>>>> > >>>>> > >>>>> https://www.linkedin.com/in/frantisekborsik > >>>>> > >>>>> Signal, Telegram, WhatsApp: +421919416714 > >>>>> > >>>>> iMessage, mobile: +420775230885 > >>>>> > >>>>> Skype: casioa5302ca > >>>>> > >>>>> frantisek.borsik@gmail.com > >>>>> > >>>>> > >>>>> On Wed, Oct 1, 2025 at 11:32=E2=80=AFPM Frantisek Borsik < > >>>>> frantisek.borsik@gmail.com> > >>>>> wrote: > >>>>> > >>>>>> Let's say that I love it, channeling my inner Dave Taht. But there= were a > >>>>>> couple of voices asking if I won't consider to change it a bit, to= be > >>>>> "less > >>>>>> hostile" to our "bandwidth is king!" friends...and I was trying, b= ut this > >>>>>> was really sticky and I'm happy that it stayed this way. > >>>>>> > >>>>>> > >>>>>> All the best, > >>>>>> > >>>>>> Frank > >>>>>> > >>>>>> Frantisek (Frank) Borsik > >>>>>> > >>>>>> > >>>>>> *In loving memory of Dave T=C3=A4ht: *1965-2025 > >>>>>> > >>>>>> https://libreqos.io/2025/04/01/in-loving-memory-of-dave/ > >>>>>> > >>>>>> > >>>>>> https://www.linkedin.com/in/frantisekborsik > >>>>>> > >>>>>> Signal, Telegram, WhatsApp: +421919416714 > >>>>>> > >>>>>> iMessage, mobile: +420775230885 > >>>>>> > >>>>>> Skype: casioa5302ca > >>>>>> > >>>>>> frantisek.borsik@gmail.com > >>>>>> > >>>>>> > >>>>>> On Wed, Oct 1, 2025 at 9:25=E2=80=AFPM dan w= rote: > >>>>>> > >>>>>>> I actually really like the title ;) > >>>>>>> > >>>>>>> It's that most of the time people are told they need more bandwid= th to > >>>>>>> solve a problem, when they really need lower latency and jitter. = So the > >>>>>>> vast majority of the time 'more bandwidth' as a solution really i= s a > >>>>> lie. > >>>>>>> On Tue, Sep 30, 2025 at 2:47=E2=80=AFPM Frantisek Borsik via Libr= eQoS < > >>>>>>> libreqos@lists.bufferbloat.net> wrote: > >>>>>>> > >>>>>>>> Thanks, Jim. Well, true that - but I wanted to do it either way, > >>>>> because > >>>>>>>> of > >>>>>>>> our dear Dave and - as a conversation starter. > >>>>>>>> As @Jason Livingood said - "Bandwi= dth is > >>>>>>>> dead. Long live latency." > >>>>>>>> > >>>>>>>> > >>>>> https://pulse.internetsociety.org/blog/bandwidth-is-dead-long-live-= latency > >>>>>>>> I will do my best to get the audio/video right and to share it w= ith you > >>>>>>>> all. > >>>>>>>> > >>>>>>>> PS: Sending you separate email. > >>>>>>>> > >>>>>>>> All the best, > >>>>>>>> > >>>>>>>> Frank > >>>>>>>> > >>>>>>>> Frantisek (Frank) Borsik > >>>>>>>> > >>>>>>>> > >>>>>>>> *In loving memory of Dave T=C3=A4ht: *1965-2025 > >>>>>>>> > >>>>>>>> https://libreqos.io/2025/04/01/in-loving-memory-of-dave/ > >>>>>>>> > >>>>>>>> > >>>>>>>> https://www.linkedin.com/in/frantisekborsik > >>>>>>>> > >>>>>>>> Signal, Telegram, WhatsApp: +421919416714 > >>>>>>>> > >>>>>>>> iMessage, mobile: +420775230885 > >>>>>>>> > >>>>>>>> Skype: casioa5302ca > >>>>>>>> > >>>>>>>> frantisek.borsik@gmail.com > >>>>>>>> > >>>>>>>> > >>>>>>>> On Tue, Sep 30, 2025 at 10:25=E2=80=AFPM James Forster < > >>>>> jim@connectivitycap.com> > >>>>>>>> wrote: > >>>>>>>> > >>>>>>>>> Wow, that=E2=80=99s fantastic, Frantisek! Great work making th= is happen. > >>>>>>>>> > >>>>>>>>> These sort of titles aren=E2=80=99t my favorite. I think I unde= rstand the > >>>>>>>>> sentiment but find the issues more nuanced than that. :-) > >>>>>>>>> > >>>>>>>>> If you can get clear audio, not much quality is needed for pane= ls and > >>>>>>>>> talking beads. Best would be a feed right into an iPhone/andr= oid. > >>>>>>>>> > >>>>>>>>> Jim > >>>>>>>> _______________________________________________ > >>>>>>>> LibreQoS mailing list -- libreqos@lists.bufferbloat.net > >>>>>>>> To unsubscribe send an email to libreqos-leave@lists.bufferbloat= .net > >>>>>>>> > >>>>> > >>>> _______________________________________________ > >>>> Starlink mailing list -- starlink@lists.bufferbloat.net > >>>> To unsubscribe send an email to starlink-leave@lists.bufferbloat.net > > _______________________________________________ > > Starlink mailing list -- starlink@lists.bufferbloat.net > > To unsubscribe send an email to starlink-leave@lists.bufferbloat.net > > -- > **************************************************************** > Dr. Ulrich Speidel > > School of Computer Science > > Room 303S.594 (City Campus) > > The University of Auckland > u.speidel@auckland.ac.nz > http://www.cs.auckland.ac.nz/~ulrich/ > **************************************************************** > > > > _______________________________________________ > Starlink mailing list -- starlink@lists.bufferbloat.net > To unsubscribe send an email to starlink-leave@lists.bufferbloat.net