Networking

Starter Activity

• Think of as many different methods of communication of data across the world e.g. Satellite
• Satellite
• Fiber optic (optical)
• Radio
• LAN Cables

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Learning Outcomes

• Understand what a network is the purpose of them.
• Understand the advantages and disadvantages of networks.
• Identify and understand 3 different styles of networks.

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What is a Network?

• A computer network is two or more computers connected together. Usually through a server.
• Computers in a network can communicate with each other.
• The network includes the computer systems, the connections and the hardware needed to allow the communication.

2 types of networks

• Local Area Networks (LANs): computers connected over a relatively small distance, usually one building or one site. E.G. a school or a hospital
• Wide Area Networks (WANs): computers connected together over larger distances, such as all branches of a company. The Internet is a WAN.

Advantages of Networks

• Computers can communicate with each other and share data and files.
• Computing power and/or storage facilities can be shared and backed up.
• Hardware such as printers can be shared.
• There is control over which programs and settings a user has access to.
• Communication across the network is cheap and fast.

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Disadvantages of Networks

• Viruses can spread rapidly
• Security (need for user id’s and passwords)
• Big problems if server crashes
• Cabling and Hardware is Expensive
• Damage to cables can cause big problems
• Need for network manager who need to be trained.

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Exam Question!

• A school with 20 stand alone PCs is considering networking them together and adding a file server.
• Consider four possible benefits of doing this.

Exam Answer

• All 20 computers will be able to print to a single printer. Without the network you would need 20 printers, or each student would have to wait until the computer with the printer attached was free.
• All 20 computers will be able to share an Internet connection, giving all the students access to the Internet.
• Students can have their own space on the file server, improving security when compared to storing the files locally on each computer.
• The file server can be backed up to tape every night keeping the students' documents safe.

Network Topology

• Go on the internet and define “network topology”
• Find 3 types of network typology.

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• Network Topology is the the configuration of a communication network.

The bus network

• workstations, servers and printers are joined to one cable (the bus)

Advantages

• easy to install
• cheap to install, as it doesn’t require much cable

Disadvantages

• if the main cable fails or gets damaged the whole network will fail
• more workstations connected equals lower performance due to datacollisions
• All see all so low security

The ring network

• Each device is connected to two other devices,
• Signals to travel around the ring.
• Packets (Data) travel in one direction and each device receives each packet in turn until the destination device receives it.

Advantages

- Transfers data quickly even if many devices

- No data collisions

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Disadvantages

- if main cable fails the network goes down.

The star network

• Each device on the network has its own cable connected to a switch or hub.
• A hub sends every packet of data to every device, whereas a switch only sends a packet of data to the destination device.

Advantages

• If one cable breaks all computers continue to work
• High performance as no data collisions

Disadvantages

• Expensive due to lots of cabling
• Extra hardware like hubs and switches
• If hub fails the network goes down

Test questions?

• http://bbc.in/cqDxES

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Common Networking Environments

Learning Outcomes

• Be able to describe some common networking environments

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Intranet

• An intranet provides information on web pages but the information can only be accessed from the local network.

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Intranet Advantages

• Free
• Easily updateable
• The web pages can be viewed using a standard web page browser.
• Useful information for specific audiences

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The Internet

• The Internet is a world-wide network of linked computers sharing a vast amount of information.

Advantages of the Internet

• Millions of people contribute information.
• Data can be rapidly added and updated to reach a huge audience.
• It can be used to sell goods to a world-wide market.

Disadvantages of the Internet

• Some useless and out of date information
• Like trying to find a needle in a haystack
• Misleading and inaccurate information
• Not regulated by any organisation
• Security problems

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Networking Quiz

• 10mins

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If you finish early follow the ‘Types of networks’ link on the GCSE intranet site to find out about different networks. You will find this under the activities section.

Learning Outcomes�You should now

• Understand the purpose of networks
• Understand the advantages and disadvantages of networks
• Be able to describe some common networking environments

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