This post is incomplete…
This post is aimed at the Matric Learner preparing for theory assessment: it covers work from the entire CAT syllabus. Much of this theory was covered in Grades 10 & 11 and should serve as revision.
Definition: a (computer) network is defined as two or more computer devices connected to each other.
The physical network is therefore made up of a variety of devices and connections:
- The devices could be any number of things: PC’s, laptops, servers, printers, Smart TV’s.
- The connections could be components ranging from UTP cable, Wi-Fi adapters, WIMAX infrastructure, routers, switches, optic fiber cables and more.
In addition to the physical components, there is software that is installed, such as operating systems for servers and firewall software.
Finally, there are a set of protocols (for example HTTP/HTTPS, FTP) and related technologies (for example encryption) that are employed on the network.
If you like technical detail and are interested in Networking as a career possibility, it is worth Googling “network OSI model”.
Network topology is the arrangement of the elements of a communication network. In CAT we describe the arrangement of various types of telecommunication networks as being a PAN, HAN, LAN, WLAN, CAN, MAN, WAN, GAN, peer-to-peer, server-client, etc.
The Internet is a public network spanning the entire globe. It is a massive network of networks. It was designed to be freely accessible to everyone. The Internet is an example of a GAN.
The World Wide Web is a service running on the Internet. It is made up of websites that contain webpages and other media such as images, videos and more. These websites and webpages are linked together using hyperlinks.
An intranet is similar to the internet in a number of ways: it is a network, it can contain a variety of resources (webpages, documents, etc). It is different in that it is not public: access is restricted to users within a company or organisation.
A Virtual Private Network is an encrypted, private network running over a public network. This enables a smaller, localised network such as a LAN in an office building to be accessible from a remote location such as a customers office or an employee’s home by extending it over the Internet.
For example, let us imagine that you worked in an office with a laptop. Whilst at the office, your laptop is able to access the office network as it is connected via a standard ethernet cable. This means being able to use all the shared resources available on the LAN: printers, file servers, intranet and Internet connection.
However, next week you will be working from home with your laptop. You have Internet access at home, but how will you access your files on the file server or the company Intranet? Via VPN access, of course! You will connect to the Internet and sign on to the VPN server. The Internet then acts as the “cable” connecting you to your office LAN. Of course, now all your classified work information is travelling over the Internet. Not to worry: the VPN server encrypts all the data travelling across the connection.
A hotspot descibes a limited space (such as a coffee shop, airport terminal, shopping mall) in which a Wi-Fi connection is made available to the public. Connecting to the hotspot may require a password. A fee may be charged or it may be free.
This is when a device such as a smartphone has the ability to share its data connection (3G/LTE etc.) with other devices (another smartphone or a laptop) so that they can access the network. This allows you to share a connection to the internet. On an Android smartphone, for example, the Mobile Hotspot feature allows you to:
- activate the Mobile Hotspot feature on your smartphone so that your friend can connect to your smartphone using Bluetooth to use your data connection or vice versa.
- you can connect a laptop to a smartphone so that the laptop can access the internet using the smartphone’s data connection
The person sharing their connection pays for the data of both users.
Advantages of a Network
- Almost instant communication
- Sharing of information
- Sharing of resources (printer, internet connection, file server etc)
- Centralisation of security, data
- Remote access
Disadvantages of a Network
- Network resources unavailable if the network is not functioning
- Additional security risks
- Once security has been compromised at any point the entire network may be at risk
- Viruses are often designed to spread over networks (“worms”)
- The extra cost of hardware and software
- Can be expensive to set up and maintain
- Requires specialised knowledge/skills
Questions from past papers
Grade 12 P2 Prelim 2018 WCED
1.5 Which ONE of the following refers to a private internal network that can be accessed only by employees outside the company building?