I saw a map of undersea internet cables the other day and it’s crazy how many branches there are. It got me wondering - if I’m (based in the UK) playing an online game from someone in Japan for example, how is the route worked out? Does my ISP know that to get to place X, the data has to be routed via cable 1, cable 2 etc. but to get to place Z it needs to go via cable 3, 4?

  • LainTrain@lemmy.dbzer0.com
    0·
    8 months ago

    But surely that can’t really be true either like if I post a selfie on Instagram in London, some guy’s Minecraft server in Minnesota can’t be receiving that and be like “oh not for me - ignore”. It just seems horribly inefficient. But maybe I’m having trouble conceptualising how fast light is? 😅

    And based on another answer ITT by FuglyDuck, it would seem that once you’ve resolved a domain you do send it to a central hub that then resolves subnets until it gets to it’s destination, so I can imagine that it does so by physically sending it down “the right cable” as it gets past each layer to get to the final destination via the recepient’s ISP, but imagining it as a giant automated telephone switchboard is all my feeble software brain can comprehend it as and that doesn’t seem right either.

    ~~Edit: well actually network switches do operate on the data link layer, but also not on the physical one?

    I guess what I’m trying to say is: if I’m sending a packet to Japan from the UK - once my packet reaches a hub of a first tier ISP, does it just go down every oceanic cable in every direction, or the one that actually is in the direction of Japan?~~

    The answer is that yes - the internet is just a telephone switchboard between what amounts to otherwise isolated networks of ISPs and exchange points physically send light down correct cables with switches:

    https://en.m.wikipedia.org/wiki/Internet_exchange_point