Networking
Introduction
Understand the OSI and TCP/IP models, network layers, and how data traverses the Internet.
Lesson goal
By the end of this lesson, you will understand the fundamentals of computer networking, the layered architecture models (OSI and TCP/IP), and how data travels across interconnected networks.
Networking is the backbone of distributed systems. Every interaction between clients, load balancers, application servers, and databases relies on network protocols to deliver packets accurately and efficiently.
The layered network model
Modern networking is organized into abstraction layers, each responsible for a distinct part of the communication lifecycle:
| Layer | Primary Responsibility | Common Protocols |
|---|---|---|
| Application | High-level data exchange and business logic | HTTP, HTTPS, WebSockets, DNS, SSH |
| Transport | End-to-end delivery, connection management, reliability | TCP, UDP, QUIC |
| Network / Internet | Addressing, packet routing across networks | IP (IPv4, IPv6), ICMP |
| Data Link & Physical | Frame transfer across local media / physical hardware | Ethernet, Wi-Fi, Fiber Optics |
How packets travel
Key Takeaways
- Packets and Frames: How payloads are packaged with headers and trailers.
- Routing vs. Switching: Finding pathways across the global internet vs. within a local area network.
- Latency and Throughput: Bandwidth constraints, round-trip time (RTT), and physical distance.
Key takeaways
- Network abstraction layers isolate hardware concerns from application logic.
- Data is encapsulated down the stack before transmission and decapsulated on the receiving end.