Networking is the backbone of modern digital communication. In this module, you will see how computers, routers, switches and other devices work together to transmit data across the globe securely and efficiently.
You will explore core terminology, common network topologies and the OSI model so you can reason about how data flows from one device to another across different layers.
"To understand cybersecurity, you first need to understand the networks your systems depend on."
🔎 What you will learn
- 🌐 The difference between LANs, WANs and the wider internet
- 🧰 The role of key network devices such as switches, routers, bridges and hubs
- 🕸️ How common network topologies like star, bus and ring are structured
- 📦 How the 7-layer OSI model describes data moving through a network
🌐 Networking terminology
- LAN: A Local Area Network covering small spaces like homes or offices.
- WAN: A Wide Area Network that spans large geographic regions.
- Internet: A global interconnection of networks that allows information sharing worldwide.
🧰 Key network devices
- 🔌 Switch: Connects devices within the same network and handles packet forwarding.
- 🌍 Router: Forwards data between networks using routing tables.
- 🔗 Bridge: Joins separate network segments together.
- 🔀 Hub: Broadcasts data to all connected devices (less intelligent than a switch).
🔄 Common network topologies
- ⭐ Star: All devices connect to a central hub (usually a switch).
- 🚌 Bus: All devices share a single communication line (backbone).
- 🔁 Ring: Each device connects to two others, forming a closed loop.
📦 The OSI model: 7 layers
The OSI model (Open Systems Interconnection) describes how data travels from one device to another in a network. Each layer has its own responsibilities:
- 1️⃣ Physical: Transmission media and hardware such as cables and switches.
- 2️⃣ Data Link: MAC addresses, frame formatting and basic error detection.
- 3️⃣ Network: Routing and IP addressing. Routers operate at this layer.
- 4️⃣ Transport: Reliable data transfer using protocols such as TCP and UDP.
- 5️⃣ Session: Starting, managing and ending communication sessions.
- 6️⃣ Presentation: Data formatting, compression and encryption.
- 7️⃣ Application: End-user interaction through protocols such as HTTP, FTP and DNS.
💡 Tip: Remember the OSI layers with this phrase: "Please Do Not Throw Sausage Pizza Away" - Physical, Data Link, Network, Transport, Session, Presentation, Application.
