Networking: Overview / Recap & Revise, Part 2

Explanation: This is the second of two pages that helps you recap and revise the Computer Science “Networking” module. It could also function as a launch page to give you an overview and to “signpost” you to the right pages in the right order if this is the first time you’ve come to this topic (e.g. you’ve just joined the school).

This whole module is about networking – that is, connecting computers together so that they can do more. It does not automatically mean “the Internet”, but that can be part of it. You could have network in an office or home that goes nowhere near the Internet, and is just used to share printers and scanners, to share file servers, and to allow users to share work and collaborate (e.g. via email). In Part 1, we looked at what a network is, the different types, the hardware you need to make one and the different types of connection you can have between computers. In this part, we look at services available on the Internet and the World Wide Web, different network architectures, and virtual networks.

Internet Services

In the next two lessons (i.e. this one and the next one) we’re looking at services specific to the Internet (although there is some overlap with networking in general). It’s not just websites and web pages, the Internet carries a lot of other traffic too. We also look at “The Cloud”, and the subtle differences between “cloud storage” and “cloud computing”.
Have a look at the content and tasks in the main lesson, Year 9 – Computing – Networking – Internet Services, then have a go at the tasks below.

Task

1) List at least three Internet applications apart from the World Wide Web.
2) What is cloud storage? Give an example, two advantages and two disadvantages.
3) Stretch: Are there any files that you perhaps shouldn’t store on the cloud? Give some examples, and explain why.

Web Services

In this lesson, we (finally!) focus on the WWW – what are web browsers, how do web pages get to your browser, and how do websites work?
Have a look at the content and tasks in the main lesson, Year 9 – Computing – Networking – Web Services, then have a go at the tasks below.

Task

1) What languages are used for writing web pages?
2) What is a URL? Stretch: break down the parts of an URL and explain what each part is.
3) DNS: what does it stand for, what does it do? Why do we need it? How does it work?

Network Architectures

In this lesson, we look at different ways of arranging networks (like the architecture of a building is how it was designed and arranged, similarly, the architecture of a network is the design, arrangement and topology of it), including the client/server arrangement mentioned when we were looking at the WWW in the previous lesson, and peer-to-peer networks. Have a look at the content and tasks in the main lesson, Year 9 – Computing – Networking -Client/Server and Peer to Peer, then have a go at the tasks below.

Task

1) What is a server? Give an example.
2) What is a client? Give an example.
3) What does peer-to-peer mean? How is it different to client/server?
3) Stretch: compare and contrast client/server with peer-to-peer. Give an example application that would particularly suit each one.

Virtual Networks

Lastly, we come to virtual networks. Virtual means “not really there”; virtual networks are networks that look like separate networks, but they’re actually part of a wider network, they just behave as if they’re separate. There are several reasons for wanting to do this – it could be security, e.g. you don’t want the Sales Department being able to see the confidential personal information being shared within the Human Resources / Personnel Department, and you don’t want anyone seeing information about the CEO’s salary that only she and the Accounts Department should know about. One way to do this is to encrypt files, or to grant different permissions to different files and folders on the server – but setting up virtual networks makes it even more water-tight, as the different virtual networks can’t even see each others data packets being sent at a network level.

Another example of virtual networks (of a different type) is some of the mobile phone companies – for example, Tesco Mobile. There are only four actual mobile network operators in the UK with licences to built and operate mobile phone networks – Vodafone (one of the original two UK networks), O2 (originally BT Cellnet, the second of the original two UK networks), EE (a merger of Orange & T-Mobile née Mercury One-2-One) and Three (a relative newcomer that arrived when 3G was launched, hence the name). All the others are what are called “Mobile Virtual Network Operators” (MVNOs) – they run their network (branding, billing, customer services, etc.) but rent the actual infrastructure (base stations, switching centres, etc.) from one of the “real” four. Other examples, in addition to Tesco Mobile (which actually runs on O2 in the UK), include Virgin Media (over EE), Lycamobile (O2) and Lebara (Vodafone).

Have a look at the content and tasks in the main lesson, Year 9 – Computing – Networking – Virtual Networks, then have a go at the tasks below.

Task

1) What does “virtual” mean, generally? What is a virtual network?
2) What are the advantages of virtual networks?
3) Stretch: You may have heard about Virtual Private Networks (VPNs) – what are they, and what are the advantages of them? Why are they a good idea nowadays?

Quizizz

To wrap up your learning on this, try this Quizizz quiz, “Year 9 – Computing – Networking – Overview, Part 2“.