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=Networks = = = **A network** is a group of two or more computers linked together so that they can share resources and can comunicated with one another **A LAN** is local area network, likely to be in the same room, building, department, school or workplace. **A WAN** stands for wide area network where the computer communicate with each other over telephone cables 

Advantages of LANs

 * software and data files can be shared by many users
 * users can work together on a single shared document

Disadvantages of LANs

 * Set up cost is higher than individual computers(cables,server have to be installed)
 * Greater risk of data corruption. Data being tampered with.
 * Greater risk of viruses, if one computer gets a virus it will spread through out the network.
 * If the server breaks down the entire network will not work.

=Client Server Network Diagram = <span style="color: rgb(255, 0, 0); font-family: Arial,Helvetica,sans-serif;">**A client server network is** a way to describe a relationship between two computer programs in which one program, the client program, makes a service request to another, the server program

=<span style="font-family: Arial,Helvetica,sans-serif;">Peer to Peer Network Diagram = <span style="color: rgb(255, 0, 0); font-family: Arial,Helvetica,sans-serif;">**A peer to peer network is** a network where all the computers are connected together, and every file and document is shared by the servers.

=<span style="font-family: Arial,Helvetica,sans-serif;">Cabled LANs = <span style="font-family: Arial,Helvetica,sans-serif;"><span style="color: rgb(255, 0, 0);">**Twisted pair is** a copper caple, which is twisted in order to reduce the interferance of the signal <span style="color: rgb(255, 0, 0);">**Fibre optic is** <span style="color: rgb(0, 0, 0);">a fibre optic cables enable large volumes of digital data to be transmitted extremely fast and virtually error-free =<span style="font-family: Arial,Helvetica,sans-serif;">BUS Network Diagram =
 * NIC is**

<span style="font-family: Arial,Helvetica,sans-serif;">Advantages

 * 1) <span style="font-family: Arial,Helvetica,sans-serif;">Easy to install
 * 2) <span style="font-family: Arial,Helvetica,sans-serif;">Easy to add extra workstations
 * 3) <span style="font-family: Arial,Helvetica,sans-serif;">Best choice for temporary networks
 * 4) <span style="font-family: Arial,Helvetica,sans-serif;">Extending the network is very easy. New erquipment can be connected to it by simply attaching it to the end of the network or adding a short spur
 * 5) <span style="font-family: Arial,Helvetica,sans-serif;">Only a single network cable needs to be installed

<span style="font-family: Arial,Helvetica,sans-serif;">Disadvantages
=<span style="font-family: Arial,Helvetica,sans-serif;"> = =<span style="font-family: Arial,Helvetica,sans-serif;">Star Topology Diagram =
 * 1) <span style="font-family: Arial,Helvetica,sans-serif;">If there is problem, the entire network stops working
 * 2) <span style="font-family: Arial,Helvetica,sans-serif;">Low security-every workstation can see all of the data in the network.
 * 3) <span style="font-family: Arial,Helvetica,sans-serif;">Any problem with the mains cable may cause the whole network to malfunction
 * 4) <span style="font-family: Arial,Helvetica,sans-serif;">Data travels in both directions along the network cable so that packets of data may collide. This may slow down the transmission speed and data may be lost

<span style="font-family: Arial,Helvetica,sans-serif;">Advantages
<span style="color: rgb(255, 0, 0);">
 * <span style="font-family: Arial,Helvetica,sans-serif;">Easy to install and wire.
 * <span style="font-family: Arial,Helvetica,sans-serif;">No disruptions to the network then connecting or removing devices.
 * <span style="font-family: Arial,Helvetica,sans-serif;">Easy to detect faults and to remove parts

<span style="font-family: Arial,Helvetica,sans-serif;">Disadvantages
<span style="color: rgb(0, 0, 0);"> =<span style="font-family: Arial,Helvetica,sans-serif;"> = =<span style="font-family: Arial,Helvetica,sans-serif;"> = =<span style="font-family: Arial,Helvetica,sans-serif;"> = =<span style="font-family: Arial,Helvetica,sans-serif;"> = =<span style="font-family: Arial,Helvetica,sans-serif;">Ring Network Diagram =
 * <span style="font-family: Arial,Helvetica,sans-serif;">
 * <span style="font-family: Arial,Helvetica,sans-serif;">Requires more cable length than a linear topology.
 * <span style="font-family: Arial,Helvetica,sans-serif;">More expensive than linear bus topologies because of the cost of the concentrators.

<span style="font-family: Arial,Helvetica,sans-serif;">Advantages:

 * <span style="font-family: Arial,Helvetica,sans-serif;">Data only travels in one direction
 * <span style="font-family: Arial,Helvetica,sans-serif;">No data collisions
 * <span style="font-family: Arial,Helvetica,sans-serif;">Extra computers can be added in to the network easily

<span style="font-family: Arial,Helvetica,sans-serif;">Disadvantages:

 * <span style="font-family: Arial,Helvetica,sans-serif;">If one machine is switched off the network will not work
 * <span style="font-family: Arial,Helvetica,sans-serif;">If a single cable is broken the network wont work
 * <span style="font-family: Arial,Helvetica,sans-serif;">Data must go through all the computers before it reaches the final computer
 * <span style="font-family: Arial,Helvetica,sans-serif;">Difficult to identify a problemt with the network.

=<span style="font-family: Arial,Helvetica,sans-serif;">Network Transmission = <span style="color: rgb(255, 0, 0);"> <span style="font-family: Arial,Helvetica,sans-serif;">Bandwidth is **<span style="color: rgb(0, 0, 0);">the amount of data the computer is able to take in ** Broadband is =<span style="font-family: Arial,Helvetica,sans-serif;">Modem Diagram = <span style="font-family: Arial,Helvetica,sans-serif;"><span style="color: rgb(255, 0, 0);">A modem : <span style="color: rgb(0, 0, 0);">is a device which used to convert digital data to anologue data. A hub : <span style="color: rgb(0, 0, 0);">is a device which connects multiple computer in a network A bridge : Joins to computer networks together. <span style="color: rgb(255, 0, 0);">A switch: =<span style="font-family: Arial,Helvetica,sans-serif;">The Internet =

<span style="font-family: Arial,Helvetica,sans-serif;"><span style="color: rgb(255, 0, 0);">The extension is something extra you add on something.
<span style="font-family: Arial,Helvetica,sans-serif;"><span style="color: rgb(255, 0, 0);">A search engine is a tool designed to search for information on the world wide web. <span style="color: rgb(255, 0, 0);">Email is any method of creating, transmitting, or storing primarily text-based human communications with digital communications systems. <span style="color: rgb(255, 0, 0);"> <span style="font-family: Arial,Helvetica,sans-serif;">IM <span style="font-family: Arial,Helvetica,sans-serif;"> is instant <span style="color: rgb(0, 0, 0);">messenger. <span style="color: rgb(255, 0, 0);">An intranet is a private computer network that uses Internet technologies to securely share any part of an organization's information or operational systems with its employees. <span style="color: rgb(255, 0, 0); font-family: Arial,Helvetica,sans-serif;"><span style="color: rgb(255, 0, 0);">A mail client is <span style="color: rgb(0, 0, 0);">computer program used to manage e-mail. <span style="color: rgb(255, 0, 0);">Webmail is <span style="color: rgb(0, 0, 0);">a web-based email. An attachment is <span style="color: rgb(0, 0, 0);">something you attach to an email. CC is <span style="color: rgb(0, 0, 0);">carbon copy. BCC is <span style="color: rgb(0, 0, 0);">blind carbon copy. Phishing is <span style="color: rgb(0, 0, 0);">a fraud designed to steal your valuable personal data, such as credit card numbers, passwords, account data, or other information. A virus is a computer program that can copy itself and infect a computer without the permission or knowledge of the user Spyware is <span style="color: rgb(0, 0, 0);">a computer software that is installed secretly/unknowingly on a personal computer to intercept or take partial control over the user's interaction with the computer, without the user's permission. Phreaking is <span style="color: rgb(0, 0, 0);">a slang term used to describe the activity of people who study, experiment with, or explore telecommunication systems, like equipment and systems connected to public telephone networks.

=<span style="font-family: Arial,Helvetica,sans-serif;">Video conferencing =

<span style="font-family: Arial,Helvetica,sans-serif;">Advantages
====<span style="font-family: Arial,Helvetica,sans-serif;">Perhaps the biggest advantage or benefit video conferencing has to offer is the ability to meet with people in remote locations without incurring travel expenses or other expenses associated with face to face communication.<span style="color: rgb(255, 0, 0);"> ====

<span style="font-family: Arial,Helvetica,sans-serif;">Disadvantages
===<span style="font-family: Arial,Helvetica,sans-serif;"># # # FTP is a File Transfer Protocol for exchanging and manipulating files over a TCP ( Transmission Control Protocol ) computer network. Spam is unsolicited ( not asked ) or undesired email messages. A firewall is an integrated collection of security measures designed to prevent unauthorized access to an information system or network. Parental control software is a software which allows a parent to monitor or limit what a child can see or do and/or time-limit these activities. Hacking is using unauthorized methods to bypass the security mechanisms of an information system or network. Piracy is the act of plagiarizing for example taking someone's words or ideas as if they were your own. === <span style="color: rgb(255, 0, 0);"> <span style="font-family: Arial,Helvetica,sans-serif;">*
 * <span style="font-family: Arial,Helvetica,sans-serif;">when one of the computers has problems with network, the other computers will be affected too

[] http://docs.google.com/Presentation?docid=dd4xbfxq_4g2v62947 <span style="font-family: Arial,Helvetica,sans-serif;">
 * <span style="font-family: Arial,Helvetica,sans-serif;">the initial setup cost are higher than for the same number of individual computers, as a served and network cabling have to be installed.
 * <span style="font-family: Arial,Helvetica,sans-serif;">if the server breaks down the entire network will not function