Networking is the backbone of modern digital communication. In this module, you’ll learn how computers, routers, switches, and other devices work together to transmit data across the globe — securely and efficiently.
🌐 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 (cables, switches).
- 2️⃣ Data Link: MAC addresses, frame formatting, error detection.
- 3️⃣ Network: Routing and IP addressing (Routers live here).
- 4️⃣ Transport: Reliable data transfer (TCP, UDP).
- 5️⃣ Session: Session control between applications (start/stop).
- 6️⃣ Presentation: Data formatting, compression, encryption.
- 7️⃣ Application: End-user interaction (e.g., HTTP, FTP, DNS).
💡 Tip: Remember the OSI layers with this phrase: "Please Do Not Throw Sausage Pizza Away" — Physical, Data Link, Network, Transport, Session, Presentation, Application.