networks. what is a computer network? a network is two or more computers that are linked together so...
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Networks
Networks
What is a computer network?
A network is two or more computers that are linked together so that they are able to share resources.
Networks
Shared resources include
• Hardware – printers, scanners, storage, etc.
• Software – need only be installed on one computer.
• Data (e.g. database files).• An Internet connection.
Networks
LANs and WANs
Local area networks:• Confined to a small area. • Usually located in a single
building. • Use cable, wireless,
infrared and microwave links that are usually owned by the organization.
• Cheap to build.• Cheap to run.
Wide area networks:• Cover a wide geographical
area (i.e., between cities, countries and even continents).
• In lots of different buildings and cities, countries, etc.
• Use more expensive telecommunication links that are supplied by telecom companies.
• Expensive to build.• Expensive to run.
Networks
An ICT network consists of
• Hardware/communication devices• Network software• Data transfer media
Networks
Communication devices
A network interface card:
• prepares data for sending over the network
• sends the data• controls the flow of
data.
Networks
Communication devices
A hub:• is used to join
computers in a network
• allows the connection of cables
• allows the sharing of files and Internet access
Networks
Communication devices
A switch:• is similar to a hub but more intelligent• can look at a packet of data to decide
where it should go• reduces the number of packets of data
on a network, which speeds it up
Networks
Communication devices
A router:• can be wired or
wireless• is used to join
several networks together
• is often used to connect several computers in the home to the Internet
Networks
Network software
Network software consists of:• Network operating systems – specialist
operating systems designed specifically for networks.
• Network management software – used to help a network manager run a network by keeping track of software, keeping software up-to-date, installing software security patches, helping to manage the help-desk, etc.
Networks
Data transfer media
The medium/method by which the data istransferred in anetwork can be:
• metal wire• fibre optic cable• wireless.