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Fundamental of computer networks

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  1. Fundamental of computer networks What is a computer network?

  2. Learning objectives • Explain what the internet is • Explain the difference between the world wide web and the internet • Explain what a computer network is • Discuss the advantages and disadvantages of a computer network • Describe the following types of computer networks • Personal area network (PAN) • Local area network (LAN) • Wide area network (WAN)

  3. The internet and World wide web • The internet is a global network of interconnected computers. It allows data to be exchanged between computers and devices using TCP/IP. The internet has be around since the 1960s. • While the internet refers to the hardware, the world wide web (WWW) is a service that has web pages and other data that runs on the internet. The WWW was developed in the early 1990s by Tim Berners Lee.

  4. Structure of the internet • Individual devices are attached to a local area network, which in turn are connected to wide area networks. The internet is a network of wide area networks and is itself is a wide are network. • Tier 1 networks are considered the backbone of the internet. These are fibre optic cables that link different parts of the world and include cables that cross ocean floors including across the Atlantic ocean. • Tier 2 networks are regionally based and allow connectivity between large organisations such as universities. • Internet service provides of Tier 3 networks enable internet access for homes and small businesses.

  5. Computer network • In a network, a set of computers are connected to one another, so that they can communicate and share resources. Resources can include applications, files and hardware such as printers. • Computers can be connected via cables or wirelessly using radio waves to communicate. • It also makes management of computers easier because software updates can be sent to computers over the network and users on a network can login to any computer. • In contrast to a networked computer, a stand alone computer is a device that is not networked and is isolated from other devices, so cannot communicate and share resources.

  6. Research and discuss:What are the benefits and risks associated with a computer network?

  7. Advantages of a network • Can share resources such as printers and applications • Allows communication for instance by email, instant messaging and can transfer files easily. • Allows easier network management for instance it is easier to backup data onto a central fileserver and updates can be sent to all computers

  8. Disadvantages of a network • Greater risk of security as computers can be hacked especially if they are connected to the internet. • Viruses can spread from one computer to another • If there is any problem with any shared resource, for instance if the file server goes down, then this can impact the whole network.

  9. Task: Describe the following types of computer networks • Personal area network (PAN) • Local area network (LAN) • Wide area network (WAN)

  10. Personal Area Network (PAN) • This is a network set up around an individual person. Many people have multiple devices such as tablets, phones and computers. A personal area network (PAN) allows these devices to be connected together. • A Bluetooth PAN uses radio waves to communicate wirelessly between devices over a short range of a few metres. One of the devices acts as a main controlling unit through which all the other devices communicate.

  11. Local Area Network (LAN) • A local area network covers a relatively small geographical area typically extends over the range of a single organisation such as a university campus, school site. • LANs are typically managed by a single organisation.

  12. Wide Area Network (WAN) • A wide area network is made up of many local area networks and covers a much wider geographical area. • The internet the ultimate wide area of networks. It is a network of networks and allows billions of devices to be interconnected. • In principal no single person or organisation has control over a WAN. However, some authoritarian governments such as China and North Korea control the countrywide WANs.

  13. Plenary Questions • What is the difference between a local area network and a wide area network? • What are the advantages and disadvantages of networked computers over stand alone computers?

  14. Homework • AQA paper 1 Q8 2015