Overview

Networking is how computers talk to each other. It’s the plumbing of the digital age. Without it, a computer is just a fancy calculator.

Core Idea

The core idea is Protocols. Computers need agreed-upon rules (languages) to understand each other. “I speak TCP, do you?”

Formal Definition

A computer network is a set of computers sharing resources located on or provided by network nodes.

Intuition

  • The Postal Service:
    • Data: The letter.
    • Packet: The envelope.
    • IP Address: The house address.
    • Router: The post office sorting facility.
    • TCP: The certified mail receipt (guarantees delivery).
    • UDP: Throwing the letter on the porch (fast, but might get lost).

Examples

  • The Internet: The network of networks.
  • DNS (Domain Name System): The phonebook of the internet. It turns “google.com” into “142.250.190.46”.
  • HTTP: The protocol of the web. (GET, POST).

Common Misconceptions

  • Misconception: The Web is the Internet.
    • Correction: The Internet is the infrastructure (roads). The Web is just one service on top of it (traffic). Email is another.
  • Misconception: WiFi is the Internet.
    • Correction: WiFi is just the wireless link to your router.

Applications

  • Streaming: Netflix uses UDP (or similar) because if you drop a pixel, it doesn’t matter, but speed does.
  • Banking: Uses TCP because every penny must arrive.

Criticism and Limitations

  • Latency: The speed of light is a hard limit. You can’t ping Australia instantly.

Further Reading

  • Computer Networking: A Top-Down Approach by Kurose and Ross