Overview

Networks connect the world. From the WiFi in your house to the undersea cables linking continents, networking is the plumbing of the digital age.

Core Idea

Packet Switching: Instead of a dedicated line (like old phones), data is chopped into small chunks (“packets”) that take different routes to the destination and are reassembled there. This is efficient and robust.

Formal Definition (if applicable)

OSI Model (Open Systems Interconnection): A conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to its underlying internal structure and technology. It has 7 layers (Physical, Data Link, Network, Transport, Session, Presentation, Application).

Intuition

Sending an email is like mailing a letter.

  1. Application: You write the letter.
  2. Transport: You put it in an envelope (TCP ensures it arrives).
  3. Network: The post office decides the route (IP address).
  4. Physical: The truck carries it.

Examples

  • The Internet: A network of networks.
  • LAN (Local Area Network): Your home WiFi.
  • VPN (Virtual Private Network): A secure tunnel through the public internet.

Common Misconceptions

  • “The Web and the Internet are the same.” (The Internet is the infrastructure; the Web is a service running on top of it, like email or Skype.)
  • “Bandwidth = Speed.” (Bandwidth is width of the pipe; Latency is the speed of the water.)
  • DNS (Domain Name System): The phonebook of the internet (translates google.com to 142.250.190.46).
  • HTTP/HTTPS: The protocol for transferring web pages.
  • Firewall: A security device that monitors network traffic.

Applications

  • Streaming: Netflix uses adaptive bitrate streaming to handle network fluctuations.
  • Gaming: Low latency (ping) is critical.
  • IoT: Connecting billions of devices.

Criticism / Limitations

The internet was designed for trust, not security. Retrofitting security (like HTTPS and DNSSEC) is an ongoing battle.

Further Reading

  • Kurose & Ross, Computer Networking: A Top-Down Approach
  • Tanenbaum, Computer Networks