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Semicolony ELI5 · comic

TCP vs UDP.

Registered mail that is tracked and re-sent, versus postcards you fire off and hope arrive.

  1. Sign here. And here.
    #1 #2 #3
    1

    TCP is registered mail: every chunk numbered, tracked, and signed for.

  2. gone! re-send #4
    2

    Lose a piece and it’s noticed and sent again — so it all arrives, in order.

  3. all waiting… #3 #4 ? #5 #6 #7
    3

    The catch: everything behind a lost piece waits for the resend (head-of-line blocking).

  4. No time, go go go!
    FWOOMP
    4

    UDP is a postcard cannon: fired off fast, no receipts, no resending.

  5. 5

    Some arrive late, out of order, or not at all — and UDP genuinely doesn’t care.

  6. TCP files · email every byte counts UDP calls · video fast & live vs
    6

    Every byte matters (files, email)? TCP. Fast-and-live (calls, video, games)? UDP.

Same goal — move data — two very different deals about what happens on the way.
Semicolony semicolony.dev/eli5/tcp-vs-udp/comic
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