back to article How Google uses mirrors to dynamically reconfigure its networks

Google has scaled its network capacity from over one petabit per second to beyond six petabits per second since 2015, and some of that growth has come from switches that bounce optical signals off an array of mirrors to redirect traffic. As our sibling site The Next Platform reported in 2015, Google calls its datacenter …

  1. Gene Cash Silver badge


    Are you saying this is done dynamically?

    1. Francis Boyle Silver badge

      Holy pleonasm Batman

      It's so dynamic even the Dynamic Duo would be dynamically envious.

  2. Alan J. Wylie

    An old patent: "Device for controlling a light beam"

    That reminds me of this patent from 1968.

    Otto Frisch founded the first company I worked for after leaving University.

  3. Dinanziame Silver badge

    My mind is full of questions, but mainly I want to know why the number is 136.

    1. FILE_ID.DIZ

      A common fiber bundle size is 144. Perhaps 136 is used for production, the remainder is for spares or used in out-of-plane management comms?

      No real clue, however... just a guess.

  4. Tom66

    How Google uses mirrors dynamically reconfigure its networks dynamically,

    As opposed to dynamically reconfiguring its networks statically?

    1. diodesign (Written by Reg staff) Silver badge

      Re: How Google uses mirrors dynamically reconfigure its networks dynamically,

      Don't worry, we fired the AI bot that wrote that headline into /dev/null

      It's fixed - don't forget to email if you spot something wrong.


  5. zuckzuckgo Silver badge

    I always suspected that Google was just smoke and mirrors. Now we just need to identify the smoke.

  6. aregross

    Don't drop it!

    I imagine there's an alignment procedure done, either 'dynamically' or manually.

    How big (or small) are these mirrors? With only 136 fibres involved each I can't imagine them being very big.

  7. Roger Greenwood

    So in the future...

    ...when I say I can't see the network, it will literally be true!

  8. BlueJay


    I'm not sure what's new here that wasn't already achieved by photonic switches? Some Internet exchange points have been doing this since at least 2004, but maybe without the beta tag...

    1. diodesign (Written by Reg staff) Silver badge

      Re: Re-inventing

      Yeah, but the improvements are interesting.

      Well, we found them interesting. Cutting-edge network experts may not be impressed.


      1. Anonymous Coward

        Re: Re-inventing

        I found it interesting as well and I thank you for highlighting it. A pint for you and the Google boffins.

  9. martinusher Silver badge

    They're just optical switches

    They're components you can buy, they've been on sale for a decade or more. They're like small blocks that you connect fibers to that you switch using a voltage (think "optical relays"). Its likely that the 2022 version is rather more sophisticated -- and dense -- than the 2006 version.

    There are situations where physical connectivity rather than logical connectivity is useful, especially if you need to isolate circuits or you're working with optical data and you don't need to switch circuits packet by packet.

    1. diodesign (Written by Reg staff) Silver badge

      More sophisticated and dense

      Yeah that's it - it's just rad to see it detailed at Google-scale. See the paper for more info.


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