From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.17.21]) (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 2CE253CB35; Tue, 19 Dec 2017 12:55:21 -0500 (EST) Received: from [192.168.10.50] ([93.233.74.83]) by mail.gmx.com (mrgmx102 [212.227.17.168]) with ESMTPSA (Nemesis) id 0Me5Q2-1edviY0SvW-00PwaL; Tue, 19 Dec 2017 18:55:20 +0100 To: Mikael Abrahamsson Cc: "cerowrt-devel@lists.bufferbloat.net" , bloat References: <87bmjff7l6.fsf_-_@nemesis.taht.net> <1512417597.091724124@apps.rackspace.com> <87wp1rbxo8.fsf@nemesis.taht.net> <1ee44b12-1247-1830-0388-63a4c74fb6d2@gmx.net> From: Matthias Tafelmeier Message-ID: <614a9a1f-67a9-de9c-d906-589bb84eab4d@gmx.net> User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha384; protocol="application/pgp-signature"; boundary="hX0bsEgT0OngUBRwUkaarxkVdd0d6Uhib" X-Provags-ID: V03:K0:EUIu0tqbLCdfNOxaBvgMS0YJFO73PdfkJeaCkGlGXtFD24QMsrJ IUf4gBzvWFMgYKpr8YJB1FZTUFXdxYqZkDi1/3aRHFLagifXVO1wrwGZaoksllas/Bt83/k vbrugvJNCfz2F0RriuyIvmlCGwdzwx8wKwCuynYmBTYx3NWMqLjkuiWNdlI/ULh7ikaF+WJ 03XtJOFRuNowow75kCmnw== X-UI-Out-Filterresults: notjunk:1;V01:K0:GTW3QK5aW9M=:gQOYwDjwDu8HZ9NXvFB3nR uU97Bv4yMEumFKgN5xZdVxv8aIIObkkAFditVI1Q/k+A1Q1BHpLrZOiX6twnXC6duamp6YrnT gaKlzm/tm8njMHM8SJHZmPtluX4tzwarejm4gvlCvhonwccuFOC6Ey+FA1AkhMsF/qhQzufnc +M+nWC9bk3O7yRzzdetHwfiZRCcMTGUKZ2nNikbnMZg5o8s6jyTkUvhIPOjP35Ab0LCsSfaZ5 4q26nD696+YxdSJRHvpn9eAl5auvn5hOKFOlohDcNxoSmMGX73/uFLESxFRi9JY147UWf+nOq iYA9ZorM5z87DHHBMdV7CM5S06PXgVDA97Pri4VNv9PEhtlAghmZrjNQqp5kkZhmvSekoC/ZZ u3E6s21NSrcJGNSNFpA/IXjfYK2QzX8SwpgnOgvLiCQ4mv9Juyp+eEsBZipiQbANQWC1ogErP oXaj8B8Du2XD15wjKZdZFQAeuzrXkgyPbztb3Qutk0Bq66t5q2dHp6ob++zGtn+EHGP8pdVty swT7KpgnR8m5FsyWget+5GDZr51oYs8uArRkHYcVabbBIDwuUj8InIuekAXpk6hmk4e/mY3Ms uJjGB9NutpAD20ZNor/0uVHcKo6WdgCxp0reYkdVBkWd3YrzIMueQeyJkw1Sg/5HUo2kt773P 8/mIuVuUho+dotMRIjFW44Q2xdc6HT2Lirc8Y9Xrps5omXABsrGmu/e9GAe1EyDldv5Gbuo8l oNVC+frYacyzwxf/IuemenrP+atHcy1wH8SF1TWLs3QexL6EQgbz1KEt20YiP/RaFRTYX2vgT h+0dzBJ9fJZQWOxGQunTAo+q+lpIQ== X-Mailman-Approved-At: Mon, 30 Mar 2020 07:21:14 -0400 Subject: Re: [Cerowrt-devel] [Bloat] DC behaviors today X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Date: Tue, 19 Dec 2017 17:55:22 -0000 X-Original-Date: Tue, 19 Dec 2017 18:55:18 +0100 X-List-Received-Date: Tue, 19 Dec 2017 17:55:22 -0000 This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --hX0bsEgT0OngUBRwUkaarxkVdd0d6Uhib Content-Type: multipart/mixed; boundary="97cdrlSh4Iqad9nVSg0V2eFgt2CQ8Rid8"; protected-headers="v1" From: Matthias Tafelmeier To: Mikael Abrahamsson Cc: "cerowrt-devel@lists.bufferbloat.net" , bloat Message-ID: <614a9a1f-67a9-de9c-d906-589bb84eab4d@gmx.net> Subject: Re: [Bloat] [Cerowrt-devel] DC behaviors today References: <87bmjff7l6.fsf_-_@nemesis.taht.net> <1512417597.091724124@apps.rackspace.com> <87wp1rbxo8.fsf@nemesis.taht.net> <1ee44b12-1247-1830-0388-63a4c74fb6d2@gmx.net> In-Reply-To: --97cdrlSh4Iqad9nVSg0V2eFgt2CQ8Rid8 Content-Type: multipart/mixed; boundary="------------AD6B8D5715E1319AD6E1129A" Content-Language: de-DE This is a multi-part message in MIME format. --------------AD6B8D5715E1319AD6E1129A Content-Type: multipart/alternative; boundary="------------160579DBBADAA0C60AC43052" --------------160579DBBADAA0C60AC43052 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable > >> What I actually wanted to posit in relation to that is that one could >> get sooner a c-cabable backbone sibling by marrying two ideas: the >> airborne concept ongoing as outlined plus what NASA is planning to >> bring about for the space backbone, e.g [1][2]. It's laser based >> instead of directed radio-wave only. Sure, both is in the speed range >> of c, apparantely, laser transmission has in addition a significantly >> higher bandwidth to offer. "10 to 100 times as much data at a time as >> radio-frequency systems"[3]. Attenuations to photons in clean >> atmospheric air are neglible (few mps - refractive index of about >> 1.0003), so actually a neglible slowdown - easily competing with top >> notch fibres (99.7% the vacuum speed of light). Sure, that's the >> ideal case, though, if cleverly done from the procurement of >> platforms and overall system steering perspective, might feasible. > > Todays laser links are in the few km per hop range, with is easily at > least one magnitude shorter than radio based equivalents. > Hold on! This is a severe oversimplifcation, isn' it. The devices you're probably referring to are in the low-end segment, dillentically and maybe terrestrially operated only - to mention a few limiting factor conceivable possibly being perceived. Certainly, there are range limiting factors when fully submerged in the near-ground atmospheric ranges. E.g. in the darkest snow storm, one cannot expect optics to be reliablly working - admitting that. Nothwithstanding, recent research[1] showed astounding achievements of FSOs even in harsh atmospheric conditions - "up to 10 gigabits per second" while in vivid movement, in heavy fog ... for a single pathed las= er. 90% mass of the atmosphere=C2=A0 is below 16=C2=A0km (52,000=C2=A0ft), th= erefore also most of it's randomness[2]. Meaning, one only had to surpass this distance to more decently unfold the capabilities of an airborne backbone. Therefore, a hierarchy of airborne vessels might be necessary. Might smaller, more numerous ones gatewaying the optics out of the dense parts of the atmosphere to the actual backbone-net borne lasers, might by doing this relaying not laser beam based. Far more mitigation techniques are conceivable. From there on, the shortcomings appear controllable. > I don't know the physics behind it, but people who have better insight > than I do tell me "it's hard" to run longer hops (if one wants any > kind of high bitrate). If one looks up what is achievable in space, where the conditions shouldn't be too different from earth atmosphere over 16=C2=A0km. Thousan= ds of kilometres for a single hop, single path. Now imagine a decent degree of multipathing. Physical intricacies are certainly a headache in this topic, though shouldn't be decisive, I'd dare to categorize the largest complexity compartment of such a system into the algorithmics for steering, converging or stabilizing the airborne components, directing the optics problerly and in time. The overall automatic or even autonomic operations to abstract it. Probably, me forming some papers wrapping this up would be worthwile. [1]https://phys.org/news/2017-08-high-bandwidth-capability-ships.html [2]https://arxiv.org/pdf/1705.10630.pdf --=20 Besten Gru=C3=9F Matthias Tafelmeier --------------160579DBBADAA0C60AC43052 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable

What I actually= wanted to posit in relation to that is that one could get sooner a c-cabable backbone sibling by marrying two ideas: the airborne concept ongoing as outlined plus what NASA is planning to bring about for the space backbone, e.g [1][2]. It's laser based instead of directed radio-wave only. Sure, both is in the speed range of c, apparantely, laser transmission has in addition a significantly higher bandwidth to offer. "10 to 100 times as much data at a time as radio-frequency systems"[3]. Attenuations to photons in clean atmospheric air are neglible (few mps - refractive index of about 1.0003), so actually a neglible slowdown - easily competing with top notch fibres (99.7% the vacuum speed of light). Sure, that's the ideal case, though, if cleverly done from the procurement of platforms and overall system steering perspective, might feasible.

Todays laser links are in the few km per hop range, with is easily at least one magnitude shorter than radio based equivalents.

Hold on! This is a severe oversimplifcation, isn' it. The devices you're probably referring to are in the low-end segment, dillentically and maybe terrestrially operated only - to mention a few limiting factor conceivable possibly being perceived.

Certainly, there are range limiting factors when fully submerged in the near-ground atmospheric ranges. E.g. in the darkest snow storm, one cannot expect optics to be reliablly working - admitting that. Nothwithstanding, recent research[1] showed astounding achievements of FSOs even in harsh atmospheric conditions - "up to 10 gigabits per second" while in vivid movement, in heavy fog ... for a single pathed laser.

90% mass of the atmosphere=C2=A0 is below 16=C2=A0km (52,000=C2=A0ft)= , therefore also most of it's randomness[2]. Meaning, one only had to surpass this distance to more decently unfold the capabilities of an airborne backbone. Therefore, a hierarchy of airborne vessels might be necessary. Might smaller, more numerous ones gatewaying the optics out of the dense parts of the atmosphere to the actual backbone-net borne lasers, might by doing this relaying not laser beam based. Far more mitigation techniques are conceivable. From there on, the shortcomings appear controllable.

I don't know the physics behind it, but people who have better insight than I do tell me "it's hard" to run longer hops (if one wants any kind of high bitrate).
If one looks up what is achievable in space, where the conditions shouldn't be too different from earth atmosphere over 16=C2=A0km. Thousands of kilometres for a single hop, single path. Now imagine a decent degree of multipathing.

Physical intricacies are certainly a headache in this topic, though shouldn't be decisive, I'd dare to categorize the largest complexity compartment of such a system into the algorithmics for steering, converging or stabilizing the airborne components, directing the optics problerly and in time. The overall automatic or even autonomic operations to abstract it.

Probably, me forming some papers wrapping this up would be worthwile.

[1]https://phys.org/news/2017-08-hi= gh-bandwidth-capability-ships.html

[2]https://arxiv.org/pdf/1705.10630.pdf

--=20
Besten Gru=C3=9F

Matthias Tafelmeier
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