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ELI5 Yahaaa

Somebody else's computer

Where Does a Website Actually Live?

A website is files on a real machine, delivered to you as small addressed packets.

1 You ask for apage2 The requestcrosses thenetwork3 A real computeranswers
A website lives on someone's machine. You are borrowing a copy.
  1. Step 1 of 5

    A website is files on a real computer.

    A machine in a buildingKept powered and cooledHolds the actual filesAnswers thousands ofpeople at once

    Somewhere there is a machine in a cooled room, plugged into power and cable, holding the actual pictures and text. Nothing lives in the air.

  2. Step 2 of 5

    Your request is chopped into packets.

    One page youasked forSplit into manysmall packetsRebuilt inorder at yourend

    A page is far too big to send in one piece, so it travels as many small chunks that are put back in order once they all arrive at your end.

  3. Step 3 of 5

    Every packet carries its own address.

    Where it is goingthe destinationaddressWhere it came fromso a reply canreturnWhich piece it isso the ordercan be rebuiltThe actual datayour slice ofthe page

    Each chunk is wrapped in a label saying where it is going, where it came from, and which piece of the whole it happens to be.

  4. Step 4 of 5

    Routers pass packets hop by hop.

    A router receives it Checks whichway looksquickest Passes it to a neighbour Repeat, hopafter hopHop

    No machine knows the whole route. Each router simply reads the address, picks whichever neighbour looks closest, and hands the packet on.

  5. Step 5 of 5

    Lost packets are simply asked for again.

    All packets arrive The page appearsOne goes missing?Your machine asks again

    Nothing guarantees delivery, so your machine keeps track of which pieces arrived and politely requests any that never turned up.

    A packet from London to Sydney crosses about 17,000 kilometres of cable and usually makes the round trip in under 300 milliseconds.

The short version

A website lives as files on a real computer somewhere, and reaches you as small addressed packets handed from router to router.

Try it yourself

On a computer, run a traceroute to a foreign website. Every line printed is one real machine your request hopped through.

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