From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.15.15]) (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 DA1793B29D; Tue, 21 Mar 2023 15:04:53 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.de; s=s31663417; t=1679425492; i=moeller0@gmx.de; bh=v1OF5fF0i1dqbDGLZiyud4VIZ1UBOIifrFR1bXknBKo=; h=X-UI-Sender-Class:Subject:From:In-Reply-To:Date:Cc:References:To; b=MyUQZmx0aDhNDHNNySR6TYT0lGA2Rvc82VZjzwBZtClXLkppjT8iQ5/jI2VBn2yKc HvtSZ5vIhTmxD33jet0OWwjtO7V06reZXldssAr0I05QS9CbEPOkpLWIpdNH+l/FyY Pb9pln9FAm7S2R7o0Ats4W5l7vx+TAcQC4R46/3Z10++wYTnDgGYtxLTh8JE9meirS Mf3gXf/dNfmq5IopOQ+YRgx0GcDlhUXXeHJW/Pw8LUkNFY5r3DDexn4qyUUxayx3Sn K8c8INCGoKlMFY8th5JHAnEWNJpKUiu17GAWJQ3eUwAuJ5048HKtedPi76e633pTBr l/ArXX2tzr9Gg== X-UI-Sender-Class: 724b4f7f-cbec-4199-ad4e-598c01a50d3a Received: from smtpclient.apple ([78.50.122.103]) by mail.gmx.net (mrgmx005 [212.227.17.190]) with ESMTPSA (Nemesis) id 1MvbFs-1qWvjh3vfC-00shGw; Tue, 21 Mar 2023 20:04:52 +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: Tue, 21 Mar 2023 20:04:51 +0100 Cc: Rich Brown , Frantisek Borsik , bloat , libreqos Content-Transfer-Encoding: quoted-printable Message-Id: References: <20230321001019.GA4531@sunf68.rd.bbc.co.uk> <46A0D5B3-FFAA-40A3-B94C-6D01C99D92EB@gmail.com> To: dan X-Mailer: Apple Mail (2.3696.120.41.1.2) X-Provags-ID: V03:K1:lOXyCNxbplcqF+57XslblnTXFpHIt8ZZWNOWcrS4T9kt65jEFJz xlAPJS9Orp4BZmrZ7vth0iWqwyEcmst+iVDyNJWG9JLv3MZf4IdyJue9TgGR92qDgwhJKHq /pj4IPy7m4D2vCQowvk/xsHruwm9rujLZnOZ7C6pI6jLSqerr0ECsLAJK1j+nkchfTJIpBL epjLT+IZptHGTr+ah6Piw== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:d8Ti0/Nwgk4=;YQUYnV969j83Ko9fmheMGxvnezW bB8sRLiIvrIpYRM19d8NA0LvYlzvsFQtQsEWeqKrk6J+dG1JKKauajxMRer3TW9jrM+jDNHFX EeNraWRlud2LsXHRaUWX1G3RSokenswD6P/Ve5Ykew3TnMbDtBoVsIlhMEfLl2w8yxz9xg9TX 4nIKVpywdA+gAiJP7HqHsY70MrGVIOLQicq+4PCEz37CxztkCHUt/w4rC/Fqs8u1suC1k8kuB JyWN2CFjqzIv9ud6XBQp0eO78H8f2nudLeG/KOlTVNcJhmNLOiXTTgTcgwsmgPoDXX/K53bzN tq8L47hYh/O4QOcwkXj4PVA8VJs66UFFfxfNJxbtY5TRXC05LK2GFaN11C4mBxlHSFK22lM8G Njfsy4HxBxjZsGJsQ11MoJ1FWdromtqgto07gF0gQcbEFN8hXJ8a8y4hMP4mzGYAcCFEVMpN0 P40hd/x2EW6NTBC3rHa9G8u2gFA20+tzBwN0jI4KpY8KjEXgl14pVkAtZfeEdajirwe0+kcq+ 7oimNjkl73lgbBQJW5mZ3plXUCnJ0ywjCDPnODnfYJNW4MHaTcrCB6kOLTzaGLLtCTJaGQGYb OZC4vVy54RdVo7ZEn1RgBO08/vz7Q/sgS4Q3V8qb7A57jWe2TjC6Yhg01qIedHjr5ISG2n4Mj TcIKhnVtPS2kBguvLr1GMha5jnYYrZsDrW1O7dbJpwiEu0IuFqPRN4mwpRPVKB75AIGJzgTvJ zPw3Lp7K4LB6RpoTveZudIfMULOdCL1HhJXhkePx2LyxJaRFFrKHP3dJcvZ1qEaRHHe2jyJYD iGI2WTH3UOzcYWzWkbrH3KQU0tOEcmaqzETCrcrocbuYZn6NC3uLFPC5YOeYOECg4rZ7fVKEC b24Y9ylzAo4LIEIo69TyHIOOPu4Otq3YrMVD68f2th05BpGf16kKzBIpMfetaV4sjk310gvaX F0rnkmf1x/HULtjkJUiDm/2HX+Q= Subject: Re: [Bloat] [Starlink] Annoyed at 5/1 Mbps... 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: Tue, 21 Mar 2023 19:04:54 -0000 Hi Dan, > On Mar 21, 2023, at 18:22, dan wrote: >=20 > GPON is TDMA so the latency is going to be at a minimum the RTT * = connected ONUs, vs DSL which is a fixed ratio/scheduler. =20 Assuming no proactive grants... are these a thing in PON or only = in DOCSIS?, but since GPON frames can be shared between ONUs how do you = derive the "RTT * connected ONUs" formula? > Standard GPON deployments are typically well over 1 second to the OLT. I read that as millisecond, which would mean 8 GPON frames... = for sending the request, processing and arbitrating all requests, assign = transmit slots and send the transmit maps back to the ONUs, which then = actually need to send the packets... RTT should not be all that = noticeable, at 20 Km the wave propagation of light in fiber would be = around 2*(20000/300000000 * 3/2)*1000 =3D 0.2 milliseconds... (not sure = what a realistic maximum length for a PON tree is, which probably = depends on a number of things anyway, but google says up to 20 Km for = GPON)... but that RTT would be the same for active ethernet... > Not that it's bad or anything, but in comparison GPON has very = 'wireless' like best case latency but without the wireless variances. All centrally scheduled link layers will have similar challenges = I guess? Kind Regards Sebastian >=20 > On Tue, Mar 21, 2023 at 6:31=E2=80=AFAM Sebastian Moeller = wrote: > I have to push back gently on this... >=20 > XG(S)-PON is gross 10Gbps (after FEC you are left with around 8,6 = Gbps), Noki's proprietary (aka not ITU) @% Gbps PON seems to be = abbreviated 25GS-PON. >=20 > Now XGS-PON allows maximally 128 end-nodes in the tree, so: > 8600/128 =3D 67.18 Mbps/subscriber >=20 > unless the ISPs royally screwed up the configuration there should be a = CIR per subscriber of around 60 Mbps. So setting your cake shaper to 50 = Mbps shpuld give you: > a) 10 times the throughput of the 5/1 Mbps DSL (ignoring overhead = compensation for a change, which likely will be in favor of PON) > b) decent low latency, round robin delay for full MTU packets between = 128 active nodes would be:=20 > packet/sec: ((8.6 * 1000^3)/(1500*8)) =3D 716666.666667 > millisec/packet: 1000 / ((8.6 * 1000^3)/(1500*8)) =3D = 0.00139534883721 > round-robin delay 128: 128 * 1000 / ((8.6 * 1000^3)/(1500*8)) = =3D 0.178604651163 milliseconds... >=20 > DSL uses a 4KHz clock so 1000/4000 =3D 0.25 millisecond = quantization > So XGS-PON has at least theoretical potential to deliver lower latency = than DSL, but the details depend on if/how packets are aggregated. = HOWEVER the 125=C2=B5sec GPON frames can be shared between different = ONUs in upstream and downstream direction... so these are not a hard = quantisation but more the interval between control information required = for the access grant cycle... >=20 > c) robustness against RF noise sources and electricity/lightning >=20 > So I am not su sure I would prefer the 5/1 (A)DSL over a PON...=20 >=20 > That however is orthogonal to me preferring a competent ISP that takes = care of keeping latency under load at bay. >=20 >=20 >=20 > > On Mar 21, 2023, at 12:26, Rich Brown via Starlink = wrote: > >=20 > >=20 > >=20 > >> On Mar 21, 2023, at 1:21 AM, Frantisek Borsik via Rpm = wrote: > >>=20 > >> Now, I hope to really piss You off with the following statement = :-P but: > >>=20 > >> even sub 5/1 Mbps =E2=80=9Cbroadband=E2=80=9D in Africa with = bufferbloat fixed on as many hops along the internet journey from a data = center to the customers mobile device (or with just LibreQoS middle box = in the ISP=E2=80=99s network) is feeling way better than 25Gbps XG-PON. = The only time the XG-PON guy could really feel like a king of the world = would be during his speedtest. > >=20 > > Nope. Sorry - this doesn't piss me off :-) It's just true.=20 > >=20 > > - 7mbps/768kbps DSL with an IQrouter works fine for two simultaneous = Zoom conferences. (Even though no one would think that it's fast.) > > - I recommend people on a budget drop their ISP speed so they can = afford a router that does SQM = https://forum.openwrt.org/t/so-you-have-500mbps-1gbps-fiber-and-need-a-rou= ter-read-this-first/90305/40 >=20 > Even simpler, even on a 100Gbps link nobody stops you from = setting your shaper to 50/10 if that is all your router can deliver (and = I agree if there are cheaper plans closer to the 50/10 it makes economic = sense to scale down the plan)... >=20 >=20 > >=20 > > The people that get annoyed are those who just upgraded to 1Gbps = service and still are getting fragged in their games. > >=20 > > Rich > > _______________________________________________ > > Starlink mailing list > > Starlink@lists.bufferbloat.net > > https://lists.bufferbloat.net/listinfo/starlink >=20