Fundamentals of Networking

AQA 4.7.1 — Fundamentals of networking

Retrieval: Sequence 8 covered everything happening inside one machine — its processor, memory and storage. This lesson opens up a genuinely different question: how do separate machines exchange data with each other at all?

Key vocabulary

Network — two or more devices connected together so they can exchange data and share resources.
Node — any device connected to a network (a computer, printer, server, phone).
LAN (Local Area Network) — a network confined to one site, owned and controlled entirely by one organisation.
WAN (Wide Area Network) — a network spanning multiple sites, typically relying on third-party infrastructure (e.g. telecoms companies) to connect them.
Bandwidth — the maximum amount of data a connection can carry per second.

Understand — a network is about sharing, not just connecting

Physically connecting two devices with a cable doesn't automatically make a useful network — what actually matters is what that connection lets devices do: share files, share hardware like a single printer between many computers, communicate directly, and access resources (like the Internet) collectively rather than each device needing its own separate connection.

Visualise — LAN vs WAN

LAN (one school site):
  [PC] [PC] [PC] ─── switch ─── [Printer] [Server]
  (all owned and controlled by the school itself)

WAN (a company with three branches):
  [Branch A LAN] ──┐
  [Branch B LAN] ──┼── (leased lines / the Internet, owned by a telecoms provider)
  [Branch C LAN] ──┘

A LAN is entirely within one organisation's own control, on one site. A WAN connects separate LANs together across distance, and almost always depends on infrastructure the organisation itself doesn't own.

Apply to scenario — LAN or WAN?

For each organisation, decide whether it primarily needs a LAN, a WAN, or both, and justify your answer:

A single-site secondary school with computers in every classroom.
A supermarket chain with 40 stores across the country, each needing to share stock and sales data with head office.
A single small dental practice with three computers in one building.

(1: LAN — one site, entirely under the school's own control. 2: WAN — connecting many separate sites across distance needs third-party infrastructure between them, though each individual store would still run its own internal LAN too. 3: LAN — small, single-site, no need to connect to any other location.)

Analyse — advantages and disadvantages of networking

Advantage	Disadvantage
Shared access to hardware (one printer for many users) and files, avoiding costly duplication	A single point of failure — if the network goes down, every connected device may lose access to shared resources
Centralised management of software updates, backups and user accounts	A larger attack surface — every connected device is a potential route in for a security threat (covered fully in Network Security)
Easy communication and collaboration between users on the same network	Setting up and maintaining a network requires genuine technical expertise and ongoing cost

Evaluate — does every organisation need a network?

A single self-employed graphic designer working from one laptop, with no other devices to share data or hardware with, may genuinely not need a network at all — the disadvantages (cost, maintenance, security exposure) can outweigh advantages that only really apply once there's more than one device to connect. Evaluate: at what point does a growing small business's need for shared printers, shared files and centralised backups start to outweigh the cost and complexity of setting one up?

Common mistake

Treating "a network" and "the Internet" as the same thing. The Internet is one enormous, specific example of a WAN — but a private LAN inside a single building, with no connection to the outside world at all, is still a genuine, fully functional network.

Justify

A small charity with 8 staff, all working from one shared office, is deciding whether to invest in a proper managed network with a server, or to just let each of the 8 laptops work independently. Justify a recommendation, weighing the advantages and disadvantages above against the charity's specific size and single-site setup.

Looking ahead: the next lesson (Network Hardware) covers the actual physical devices — switches, routers, wireless access points — that make a network like the ones described here work in practice.