Computer Networks and the Internet
How computers communicate
Networking fundamentals
Networks connect devices so they can exchange data. The internet is a network of networks built on layered protocols. Data is broken into packets, routed across many hops, and reassembled at the destination.
Important networking terms
Transport protocols
TCP
- Reliable delivery
- Ordered data stream
- More overhead
UDP
- Less overhead
- No built-in reliability
- Useful for real-time media and simple requests
What does DNS do?
DNS translates human-readable names into network addresses.
Correct answer: Maps domain names to IP addresses
Why might UDP be chosen over TCP for some applications?
Applications like streaming or gaming may prefer speed over guaranteed delivery.
Correct answer: Because it has lower overhead and can be better for low-latency or real-time communication.
Layered thinking
Layering separates concerns: physical transmission, packet routing, transport reliability, and application behavior each live at different levels. This makes networks easier to design, troubleshoot, and evolve.
Which device forwards packets between networks?
Routers move traffic between different networks.
Correct answer: Router
What is one reason packet switching is useful?
Packet switching is flexible and robust.
Correct answer: It allows network resources to be shared efficiently among many communication flows.
Reliability is layered
Even if one protocol is unreliable, higher layers can add acknowledgments, retries, ordering, and error handling.