From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr1-x435.google.com (mail-wr1-x435.google.com [IPv6:2a00:1450:4864:20::435]) (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 2BDCE3CB37 for ; Mon, 20 Mar 2023 07:32:32 -0400 (EDT) Received: by mail-wr1-x435.google.com with SMTP id l27so1678313wrb.2 for ; Mon, 20 Mar 2023 04:32:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1679311951; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=K9owPAE2XkaK/Gol1rq17ASQ+HKYFNz3PcCs8/U8Er8=; b=lsLZdlOEAugGuVcKjKWGc6nqzwnB8sluWqbv+pkkQ4IvvyfiHyXcv1UQBa0sMpGNX8 QUK1W84Cp0wdb4b2I6ylZKKJG6Ycgh6ziMCjCnydBVF80L/WrqlBixmc4vw/rIlz9ETH /rxeIvi2PirCQVJpwt61D7JNUcNbew9rFIMJrddkc6n2/MATKodiOQ0zd6ZroMVjcKti jw+GiZLWwKIvB2i4cxKdHDyGDUzS5JvYpm9dyHo5TkkuAPDImL/eP3FSDYlNdd1yhKJ6 IZYoLJns33cah1TgcM7spXq9LdqIA1RamU4Mz0VzqvyzLeVC1iOdLOzKbB9Be39jdPTS INsw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679311951; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=K9owPAE2XkaK/Gol1rq17ASQ+HKYFNz3PcCs8/U8Er8=; b=fSDnBMIIFVpTkn1JL+zWK+9f53aybgEG8PFd60+eDcxSlRdz3JNkIxH+xXhJs/9fUe 12xSjaBMBzZPpOY7Ksuo4HXnlrSVNU1+xWXggI2XT0cZgITutoM3jDBnMLImR6ZcO3Vh xasddiOCyltRBpAtpq+WUpnmN1PHAqZVBgyvmJMT7LIgcw2NfIhVueJUrSrMhLOLiDQb AKWxcHThuof/oZ2bbTT10C1hZ/INKjivk7Q2nZGCry0VVe9vtxuRKvjW+Ub5ct6XkFbC A5czUuNeOzg9nWwai9/GFqaO4nWCbsN/8Y7VEwHopHK5sQ2w9lRl9H/+7yQo+JEGP/pt iU5w== X-Gm-Message-State: AO0yUKU2WfdIE5UG2veKBOlSEtxNNl6EV2DrkU9mXxcAinvTnh0htcir wIUCQFF1URad8uC3oOdD1Njb6S2mXsDRDB1k3ZA9qOuQ2S0= X-Google-Smtp-Source: AK7set8TQDn4EoEj0sEC90w6iTsP/WRrHzecyHBEo2Wv2s7p+bGNtwjAPXf39VtBe2leVWBcKHgeyTmbUe+2fJvtgb4= X-Received: by 2002:a5d:6dc4:0:b0:2cf:e995:afef with SMTP id d4-20020a5d6dc4000000b002cfe995afefmr3620845wrz.13.1679311950799; Mon, 20 Mar 2023 04:32:30 -0700 (PDT) MIME-Version: 1.0 References: <20230319141619.GA1774@sunf68.rd.bbc.co.uk> <94f8d9d8-75a4-0831-0a2e-020ac7175d12@vdr.net> In-Reply-To: <94f8d9d8-75a4-0831-0a2e-020ac7175d12@vdr.net> From: Dave Taht Date: Mon, 20 Mar 2023 04:32:19 -0700 Message-ID: To: Christian von der Ropp Cc: starlink@lists.bufferbloat.net Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: Re: [Starlink] mems optical switching 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: Mon, 20 Mar 2023 11:32:32 -0000 We haven't heard much about the starlink ISL links lately. Any sign they are working anywhere yet? On Sun, Mar 19, 2023 at 7:33=E2=80=AFAM Christian von der Ropp via Starlink wrote: > > All-optical switching could greatly reduce complexity and power > consumption on the satellites at the cost of flexibility. Up to 44 > satellites in an orbital plane would use individual wavelengths which > would be passed on transparently down the daisy chain and only > satellites in range of gateways would convert the optical signals back > into electrical ones, and send them down to earth while they pass a > gateway. This would result in relatively short duty cycles, hence less > power draw per orbit and less heat dissipation issues. > > Actually I've been suspecting that the SDA targets all-optical switching > for the Transport Layer constellation as I don't seen any other > immediate reason for the requirement of their OISL standard to require > wavelength switching within the ITU channel grid for LCTs (see p. 18 of > the OISL 3.0: > https://www.sda.mil/wp-content/uploads/2022/04/SDA-OCT-Standard-v3.0.pdf) > > As a matter of fact tuneable wavelenghts were already required in the > draft version of the OISL standard published in April 2020: > https://twitter.com/Megaconstellati/status/1310336728595562499 > > -Christian > > Am 19.03.2023 um 16:16 schrieb Brandon Butterworth via Starlink: > > On Sat Mar 18, 2023 at 03:19:49PM -0700, Dave Taht via Starlink wrote: > >> Today, this about google's mems switching tech hit, > > They've been talking about it since last year, seems to have got > > a hype bump recently. > > > > Who expected circuit switching to make a comeback? > > > >> I keep wondering where else it could be applied. > > They've been used for a long time, eg almost 20 years ago - > > https://archive.nanog.org/meetings/nanog32/presentations/zwart.pdf > > > > There is a goal of optical packet switching, until then you're > > limited to where there are limited flows of long enough duration > > to make the change from packet to circuit switching viable. So mostly > > automated testing. > > > > I've dabbled with the idea in an archive use case where very few of > > a large set of storage nodes need to connect to a moderate number > > of servers. For some cases we could have zero switches. The goal was > > a mostly dark infrastructure and many 1000s of storage nodes, > > removing the switches saves a lot of power. > > > > Commercial optical switches are expensive so I was looking at > > making an optical strowger as I wanted a high fan out not > > large n^2. > > > > In the mobile world they are looking at doing flexible bandwidth > > per node with coherent optics over gpon fibre plant, allocating > > variable amounts of spectrum to each, which could be adapted to a > > similar circuit model. It'd be no use to google as they want the > > full bandwidth between each node but as dwdm coherent optic costs > > come down you could imagine doing the same with a full channel > > between each pair, so like a conventional WSS but cheaper. If it > > wasn't for the optics cost I suspect they'd have done that reducing > > switching time to a channel change. > > > > brandon > > _______________________________________________ > > Starlink mailing list > > Starlink@lists.bufferbloat.net > > https://lists.bufferbloat.net/listinfo/starlink > > _______________________________________________ > Starlink mailing list > Starlink@lists.bufferbloat.net > https://lists.bufferbloat.net/listinfo/starlink --=20 Come Heckle Mar 6-9 at: https://www.understandinglatency.com/ Dave T=C3=A4ht CEO, TekLibre, LLC