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Computer Science Fundamentals · Module 6 of 10

Computer networks and the internet

Networks connect computers; the internet is a network of networks.

📖 Key ideas

  1. IP addresses identify devices; DNS turns names into IP addresses.
  2. TCP gives reliable, ordered delivery; UDP is faster but unreliable.
  3. HTTP/HTTPS carries web pages; HTTPS adds TLS encryption.
  4. Routers forward packets between networks.
  5. The TCP/IP model has layers: link, internet, transport, application.
💡 Real-life example: Like the postal system: addresses (IP), a directory (DNS), registered post (TCP) and postcards (UDP).
IP addressNumeric address of a device
DNSTurns names into IP addresses
TCPReliable ordered delivery
RouterForwards packets between networks