Networks Slide show

Networks

• What is a network?
• A network is a collection of computers connected via cable or wireless technology. Each stand-alone computer may be connected to a server or hub which in-turn connects the computer to the whole network.
• Why are they used? They are used so that files and programs are based at the server (only on some networks) but they can be accessed from anywhere in the network as long as the user has the correct access rights. Peripherals such as scanners and printers can also be shared between computers in a network.
• If a school/company have computers all over a building they can network them together so that documents can be sent to any computer in the network. This makes it easier for people within the building to access files. They can use any computer within the network to log-on to their user area and access their documents.

Advantages Disadvantages

• Files can be accessed from any computer terminal within the network.. Users can send files easily and quickly to other users of the network.. Programs and documents can be shared across the network.. Peripherals can be shared across the network.
• Adapters/CardsBusesConnectors, Plugs and SocketsData StorageHardware CompaniesInput DevicesIntegrated Circuits (ICs)KeyboardsMemoryMiceMicroprocessorsModemsMonitorsMotherboardsNetworking HardwareOutput DevicesPerformancePeripheral DevicesThe security within a network allows restrictions to be made to prevent unwanted access to data.
• Can be expensive to install and maintain.
• People may become dependent on the network.
• If the network goes down you may not be able to access the computers.
• Stand-alone computers offer more privacy.
• If one computer gets a virus it can spread across the network.

What is a LAN network?

• A computer network that spans a relatively small area. Most LANs are confined to a single building or group of buildings. However, one LAN can be connected to other LANs over any distance via telephone lines and radio waves. A system of LANs connected in this way is called a WAN.
• Most LANs connect work stations and personal computers. Each node (individual computer ) in a LAN has its own CPU with which it executes programs, but it also is able to access data and devices anywhere on the LAN. This means that many users can share expensive devices, such as a laser printer, as well as data. Users can also use the LAN to communicate with each other.

What is a WAN network?

• Wide Area Networks, or WANs, connect multiple sites to each other, such as a company with multiple office locations, or separate companies wishing to electronically link with business partners or customers. WANs are public or private forms of communication.
• A computer network that spans a relatively large geographical area. Typically, a WAN consists of two or more local-area networks (LANs). Computers connected to a wide-area network are often connected through public networks, such as the telephone system. They can also be connected through leased lines or satellites. The largest WAN in existence is the Internet.

What types of network are there?

• Star Topology: All devices are connected to a central hub. Nodes communicate across the network by passing data through the hub.
• Bus Topology: All devices are connected to a central cable, called the bus and backbone.
• Ring Topology: All devices are connected to one another in the shape of a closed loop, so that each device is connected directly to two other devices, one on either side of it.

What hardware - software is required?

• Software To set up a network you need programs which will handle the security and file management that a network requires. Programs such as Windows NT are designed with the ability to help a computer act as a server. Each computer needs the appropriate utilities installed from their operating system so that it can be used as a member of the network.
• Hardware
• You need a network card in every computer that is going to be connected to the network, you also need network cable (such as Ethernet cable). Depending on your network you may require one or more server computers, which will act as the centre of the network. Some networks have a hub, which connects all computers together.