Overview of what a network is, types of networks (LAN, WAN, MAN), network components (such as routers, switches, and servers), and the benefits of networking.
Introduction to Networks – Study Notes
1. What Is a Network?
| Term |
Definition |
| Network |
A collection of interconnected devices (nodes) that can share resources and exchange data. |
| Node |
Any device that participates in the network (e.g., computer, printer, smartphone, router). |
| Link |
The physical or logical connection between nodes (copper cable, fiber, wireless signal, etc.). |
2. Types of Networks
| Category |
Scope |
Typical Technologies |
Example Use‑Cases |
| Personal Area Network (PAN) |
< 10 m (around a single person) |
Bluetooth, Infrared, ZigBee |
Wireless headphones, fitness trackers |
| Local Area Network (LAN) |
Building or campus |
Ethernet (Cat5e/6/7), Wi‑Fi (802.11ac/ax) |
Office computers, university labs |
| Metropolitan Area Network (MAN) |
City‑wide |
Fiber optic rings, Metro Ethernet |
City government services, ISP backbones |
| Wide Area Network (WAN) |
Regional, national, or global |
MPLS, leased lines, satellite, public Internet |
Corporate branch connectivity, cloud services |
| Wireless Sensor Network (WSN) |
Distributed sensor nodes |
Low‑power radio (LoRa, 802.15.4) |
Environmental monitoring, smart agriculture |
| Virtual Private Network (VPN) |
Logical overlay over any physical network |
IPsec, SSL/TLS, WireGuard |
Secure remote access, site‑to‑site connections |
3. Network Topologies
| Topology |
Description |
Advantages |
Disadvantages |
| Bus |
All nodes share a single communication line. |
Simple, uses minimal cabling. |
Single point of failure; performance degrades with traffic. |
| Star |
Each node connects to a central hub/switch. |
Easy to manage; failure of one link doesn’t affect others. |
Hub is a single point of failure; more cabling than bus. |
| Ring |
Nodes form a closed loop; data travels in one direction. |
Predictable performance; easy to add/remove nodes. |
Failure of one link can break the ring (unless dual‑ring). |
| Mesh |
Every node may connect to multiple others. |
High redundancy, robust fault tolerance. |
Expensive and complex to implement. |
| Tree (Hierarchical) |
Combines star and bus; groups of stars connected to a backbone. |
Scalable, easy to segment. |
Backbone failure affects entire sub‑trees. |
| Hybrid |
Mix of two or more topologies (e.g., star‑mesh). |
Tailors strengths to specific needs. |
Design and troubleshooting can be complex. |
4. Core Networking Concepts
| Concept |
Brief Explanation |
| IP Addressing |
Numerical label (IPv4: 4‑byte, IPv6: 16‑byte) that uniquely identifies a host on an IP network. |
| Subnetting |
Dividing a larger network into smaller logical segments to improve management and security. |
| Routing |
Process of moving packets from source to destination across multiple networks; performed by routers using routing tables and protocols. |
| Switching |
Forwarding frames within the same LAN based on MAC addresses; performed by switches. |
| OSI Model |
7 logical layers (Physical → Data Link → Network → Transport → Session → Presentation → Application) that standardize network functions. |
| TCP/IP Model |
4 layers (Link, Internet |