Three boxes in a cupboard
A small firm moves into a new office. The technician opens the cupboard. Three boxes sit on a shelf, with cables going in and out of each.
One box faces the internet. One joins the office to the outside world. One joins every desk together.
Which box is which? And what happens if you swap two of them?
Key words
| Word | What it means |
|---|---|
| Network | computers and devices joined together so they can share data |
| Packet | a small piece of data sent over a network |
| IP address | a number that names a device on a network |
| MAC address | a number built into a network card that names that card |
| Firewall | a device or program that allows or blocks traffic using rules |
| NGFW | a next generation firewall, which also looks at which program the traffic is for |
| UTM appliance | one box that does many security jobs, such as a firewall and a virus scan |
| Router | a device that passes packets between networks |
| Switch | a device that joins devices in one network and sends data only to the right one |
| Port | a socket on a device where a cable plugs in |
The cells students fill in are left blank in this preview.
By the end of this lesson
Note
I can say what a firewall, a router and a switch each do, and where each one sits in an office network.
Starter
Have a go
Starter
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
The switch joins the desks
A switch joins all the devices in one office. Each desk cable plugs into a port on the switch.
The switch learns the MAC address of the device on every port. When data arrives, it sends it out of one port only: the port of the right device.
A switch does not leave the office. It works inside one network.
The router joins networks
A router passes packets from one network to another. It reads the IP address on each packet and picks the next step.
Your office network is one network. The internet is many others. The router is the door between them.
A home router often also gives out addresses and has Wi-Fi built in. A big firm uses separate boxes.
Quick check
Have a go
Quick check
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.