| QCA Unit | ICT at KS 3, Unit : Understanding Computer Networks. | |||
| Year Group | Year 8 | Number in class | 30 | |
| Time for lesson | 1 hour | No. of computers | 15 (minimum). | |
1.1a Using a range of ICT tools in a purposeful way to tackle questions, solve problems and create ideas and solutions of value.
1.1b Exploring and using new ICT tools as they become available.
1.1.c Applying ICT learning in a range of contexts ad in other areas of learning, work and life.
2.1a Consider systematically the information needed to solve a problem, complete a task or answer a question, and explore how it will be used.
2.1c Collect and enter quantitative and qualitative information, checking its accuracy.
2.2c Test predictions and discover patterns and relationships, exploring, evaluating and developing models by changing their rules and values.
2.2d Design information systems and suggest improvements to existing systems.
2.2e Use ICT to make things happen by planning, testing and modifying a sequence of instructions, recognising where a group of instructions needs repeating, and automating frequently used processes by constructing efficient procedures that are fit for purpose.
Aims/Learning Outcomes:
All:. Will learn about different kinds of computer networks, and their positive and negative characteristics.
Some: As above, and learn about the features of peer-to-peer networks.
Keywords: client, configure, digital, hard disc, hard-wired network, integrated services digital network, peer-to-peer, security, server, topology/topologies, wireless, user IDs/usernames.
Resources:15 networked computer terminals, internet connection, pre-prepared presentation on computer networks (see below).
Differentiation: By learning outcome, and differentiated tasks activities. Group work at different levels where the tasks are simplified/extended in terms of content and/or language for specific groups. Those in this class who are in lower ability Literacy groups to be aided by teaching support staff as available.
1. Introduction. Explain that the class are going to learn about different kinds of computer network, their capabilities, and suitability for different kinds of ICT tasks. They will found out why some organisations configure their computer networks in certain ways, and the implications of different network architecture.
On the interactive whiteboard, talk the class through the following points.
Local Area Networks (LAN).
Local area networks are run by a Server (or Servers) which runs a Client-Server system, while can also be known as a Peer-to-Peer system. These networks usually have two separate servers, a File Server to run the files and associated security from the hard disc, and a Print Server which runs the network’s printers.
The File Server controls access to the network through a system of User IDs/Usernames. It supplies all of the programmes to the Client terminals and provides back-up for saved files. All of the Client terminals have an individual ID so that the File Server knows about its activities, i.e. what files were used, and when.
Local area networks run by a File Server are only suitable for quite localised networks, i.e. in a small area, typically inside half of a square mile. Because they are close together, the File Server and Clients can be Hard-Wired together, i.e. networked by cables. Alternatively, it is now more common for Local Area Networks to use Wireless technology.
Wide Area Networks (WAN).
A Wide Area Network is made up of a system of computers linked over a much greater area than a LAN. If a single organisation needs all of its parts linked, it uses a Wide Area Network. This is normally linked by satellite or telephone network links because of the distances involved.
Connections
The easiest and cheapest way of linking computers is via hard wire cabling, such as existing telephone lines. However, these were not designed for the digital data which computes send. To use analogue-based systems, computers use either a modem or ISDN (integrated services digital network). The latter can be used to send computer data, video, or vocal information.
Wireless technology eliminates the need for hard-wired networks, but establishing the required coverage is not straightforward.
Key Questions.
What kinds of organisation might use a Local Area Network?
What kinds of organisation might use a Local Area Network?
What else might organisations have to consider when deciding between a Local Area Network and a Wide Area Network?
Network Pros and Cons.
Deciding which kind of network to use means that organisations have to carefully match their human and technical needs with their resources. In a local area network everyone is linked by the system, so there should be no communication problems. Everyone who has access to a client can receive broadcast messages from the File Server, so there is less chance that important information will be missed or lost. Access only has to be given to authorised individuals, and even their ability to access particular files or programmes may be controlled. The fact that data should not need to be transferred onto other media or drives means that the organisation’s data should be secure. Everybody shares the same printer, scanner, or other peripherals via the Print Server, so budgets can be spent on high quality, reliable products. The networked computers are sometimes called Thin Clients because they are low memory, low cost, simple platforms which do not have much capability outside of their connection to the File Server.
However, if there is a problem with the File Server or Print Server, everyone will be affected. This is why organisations have to have knowledgeable network management teams available at all times. Files will be inaccessible, and printers will be offline. The risk that this might happen often prompts people on the network to back-up information on other media, which can be a risky process for the organisation as a whole. The risks include file or programme corruption by viruses, or deliberate theft of information. There may also be problems with congestion on a local area network. Depending on the size of the system memory and quality of the connections, traffic may slow down response times and prevent clients from accessing files quickly.
Main Activity.
Task 1. In pairs at their computer, the class will complete this questionnaire using a combination of stored information and data retrieved from internet searches. Design statements expressing the positive and negative aspects of a local area network and wide area network.
Questionnaire
1. What kinds of problems are eliminated by the use of a local area network?
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2. What kinds of problems are potentially created by the use of a local area network?
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3. What are the factors which would determine whether an organisation uses a local area network or a wide area network?
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Plenary. Ask each pair to feedback their answers to each question and listen to their statements on the positive and negative aspects of a local area network and wide area network.
Relevant NC Level Descriptors.
For assessment purposes, successful completion of this lesson will enable pupils to achieve the following aspects of the ICT National Curriculum Level Descriptors.
Level 3.
Pupils use ICT to save information and to find and use appropriate stored information, following straightforward lines of enquiry. They use ICT to generate, develop, organise and present their work. This requirement will be met by the investigation of local area networks and wide area networks through networked and web based sources.
They share and exchange their ideas with others. They use sequences of instructions to…achieve specific outcomes. This requirement will be met through working in pairs and in group/class discussions about the positive, negative, and relative attributes of local area networks and wide area networks.
They describe their use of ICT and its use outside school. This will be achieved through the paired and in group/class discussions about the positive, negative, and relative attributes of local area networks and wide area networks, and their use in particular organisations.
Level 4.
Pupils add to, amend and combine different forms of information from a variety of sources. They use ICT to present information in different forms and show they are aware of the intended audience and the need for quality in their presentations. This requirement will be met by achievement of this lesson’s objectives, i.e. research on the positive, negative, and relative attributes of local area networks and wide area networks, and their use in particular organisations.
Level 5
Pupils select the information they need for different purposes, check its accuracy and organise it in a form suitable for processing. They use ICT to structure, refine and present information in different forms and styles for specific purposes and audiences. This requirement could be met by integration of information about the positive, negative, and relative attributes of local area networks and wide area networks, and its use in specially designed statements.
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