Networking Basics — LANs and Smaller Networks

This is the entry point into everything network-related in IT — get the core vocabulary solid here and Grade 11/12 networking will make far more sense.

A network is two or more computers/devices connected together so they can share resources and communicate.

Core network devices/nodes:

Device	Role
Client / workstation	A device that requests/uses a service from a server
Server	Any computer that provides a service to clients, e.g. authentication, file sharing, email — note: a server and a client can be the same physical machine
Switch	Connects multiple devices within a LAN and forwards data only to the intended recipient device
Router	Connects different networks together (e.g. your home LAN to the Internet) and directs data between them
Firewall	Monitors and filters incoming/outgoing traffic to block unauthorised access

Transmission media — how data physically travels:

Bounded (wired) media — UTP cable (Unshielded Twisted Pair, common for Ethernet) and fibre optic cable (uses light, very high speed, resistant to interference, more expensive).
Unbounded (wireless) media — microwave and radio wave transmission, used for Wi-Fi, Bluetooth and cellular data.

Classification of networks by size/reach:

Type	Meaning
PAN	Personal Area Network — very short range, e.g. Bluetooth between your phone and headphones
LAN	Local Area Network — a small geographic area, e.g. one building or home
WAN	Wide Area Network — spans a large geographic area, connecting multiple LANs, e.g. the Internet
GAN	Global Area Network — a WAN that spans the entire globe

An ADSL router in a typical home network usually combines several functions in one box: wireless access point/hotspot, firewall, switch, and the connection point to the Internet.

User profiles, rights and permissions control which network resources (files, printers, folders) a specific user is allowed to access — essential for both security and organisation on a shared network.

Reasons for using networks: communication, access to/sharing resources (e.g. printers, files), centralisation (managing data/software from one place), faster data transfer, and improved productivity.

Advantage of networking: e.g. resource sharing reduces cost (one printer for many users), centralised backups, easier communication.
Disadvantage of networking: e.g. security risk if one device is compromised, cost of network hardware/setup, network failure can disrupt many users at once.

💡 Exam Tip

Don't say 'a server is a big powerful computer' — the syllabus specifically defines a server by its role (providing a service), not by its physical size or power.