Network Navigator

Network Navigator

A **network** is two or more devices connected so they can share data and resources. To navigate this topic you need four things: the **types** of network, the **protocols** that run on them, the **layered model** they're organised into, and how they're kept **secure**. Let's chart it.

Networks come in sizes

Networks are grouped by the **area** they cover: • **PAN** (Personal Area Network): tiny, one person's own devices, e.g. earbuds paired to a phone over Bluetooth. • **LAN** (Local Area Network): a single site like a home, school or office; the organisation usually owns all the hardware. • **WAN** (Wide Area Network): spread over a large geographic area, connecting LANs together. The internet is the biggest WAN of all; its infrastructure is usually leased from third parties.

Match the scale

Name that network

A school connects all the computers across its one building so they can share a printer and files. What type of network is that?

• LAN
• WAN
• PAN

Wired vs wireless

The same LAN can connect devices with cables (**wired**, e.g. Ethernet) or over radio (**wireless**, e.g. Wi-Fi). A compare question wants both sides on the same points:

Why choose wired?

Pick the TWO genuine advantages of a **wired** connection over wireless.

• Usually faster and more reliable
• Harder to intercept. Needs physical access
• Lets devices move around freely
• Needs no cabling to install

What is a protocol?

A **protocol** is a set of **rules** governing how devices communicate, so devices made by different manufacturers can still understand each other. Examiners want a precise one-line purpose for each of the six:

Match the protocol

The exam favourite

HTTPS is used for secure websites. What does it add to plain HTTP?

• Encryption
• Faster page loading
• Support for images and video
• The ability to send email

TCP and IP team up

TCP breaks the data into _____ and reassembles them at the other end; IP then _____ each one to the right destination.

A stack of layers

Rather than one giant tangle of rules, networking is split into the **4-layer TCP/IP model**, four layers each with one job, running from the top (closest to your app) down to the hardware:

Stack the layers

Put the four TCP/IP layers in order, from the top (closest to the user's application) down to the hardware.

• Application
• Transport
• Internet
• Link

Label the stack

The four layers of the TCP/IP model, with their names removed. Put each layer in its place, top to bottom.

Locate the protocol

At which layer of the TCP/IP model does the **IP** protocol operate?

• Internet layer
• Transport layer
• Application layer
• Link layer

Why bother layering?

This is a classic grade-9 question. Layering helps because: • **Interchangeable**: each layer is self-contained, so you can change one (swap Wi-Fi for Ethernet at the Link layer) without touching the others. • **Simpler to develop and troubleshoot**: a problem can be traced to one layer, and each layer can be built and tested on its own.

Keeping it secure

Finally, four ways networks are protected: • **Authentication**: proving who you are (e.g. a username and password). • **Encryption**: scrambling data so it is useless if intercepted. • **Firewall**: filters traffic entering and leaving, blocking unauthorised access. • **MAC address filtering**: only lets known, listed devices onto the network.

Name the safeguard

Proving who a user is, with something like a username and password, is _____. Scrambling data so it is useless if intercepted is _____. Filtering traffic entering and leaving the network is the job of a _____. Allowing only known, listed devices to connect is _____.

Set up the network

A school is setting up the network in a new building. Make three decisions.

• The computer room needs the fastest, most reliable connection available, and the machines never move. Wired or wireless?
• The whole site is one campus, and the school owns all the hardware. What kind of network is that?
• Students keep connecting their own phones to the staff network. Which safeguard most directly stops unknown devices joining?