Download IGCSE ICT - Chapter 4 Computer Networks. and more Exams Nursing in PDF only on Docsity!
Igcse Ict - Chapter 4: Computer Networks
Network - correct answer Two or more computers or electrical devices connected together to enable data exchange What does a network allow you to do? - correct answer Easily share files and data Share resources such as printers and Internet connections Communicate with other network users (e-mail, instant messaging, video- conferencing, etc.) Store data centrally (using a file server) for ease of access and back-up Keep all of our settings centrally so we can use any workstation Disadvantages of networks - correct answer The computer is vulnerable to hackers If the network breaks, many tasks become very difficult Your computer can more easily be attacked by a virus Clients (workstations) - correct answer Client computers, or workstations, are the normal computers that people sit at to get their work done. Servers - correct answer Servers are special, powerful computers that provide 'services' to the client computers on the network. They are more reliable and more expensive
What do the servers do? - correct answer Provide a central, common file storage area Share hardware such as printers Controlling who can or can't have access the network Sharing Internet connections Local Area Network (LAN) - correct answer A Local Area Network is a network confined to one building or site. Often a LAN is a private network belonging to an organisation or business. Because LANs are geographically small, they usually use cables or low- power radio (wireless) for the connections. Wireless Local Area Network (WLAN) - correct answer A wireless LAN (WLAN) is a LAN that uses radio signals (WiFi) to connect computers instead of cables (like LAN). It has a wireless modem/switch at the centre that is used for sending and receiving data Wide Area Network (WAN) - correct answer A wide area network is a network that extends over a large area. A WAN is often created by joining several LANs together (businesses in different countries) by optical fibres, satellite or microwave radio links because of the large distance. E.g Internet What are the LAN network Topologies? - correct answer Hybride, ring, bus, star and tree network
A. Easy to expand DA. Expensive DA. If central device breaks, the whole network doesn't work Hybrid Network - correct answer A network that combines 2 or more of the basic topologies Difference between LAN, WLAN and WAN - correct answer A LAN is a local area network - specialises in only local area networking. A WLAN is a wireless local area network. Specialises in network communications over short distances and extends an existing local area network A WAN is a wide area network - specialises and connects many local area networks put together. Network Interface Card (NIC) - correct answer A computer that is connected to the network needs a NIC and is usually built into the motherboard Network Cable with A - correct answer Used to connect devices in a network. They have faster data transfer speeds and are less open to hacking Network Hub - correct answer A device that connects a number of computers together to make a LAN. If it receives a message, it sends it to every computer known as broadcasting data packets to every computer in a LAN.
Switch - correct answer Similar to a hub - connects a number of computers to make a LAN but is more smarter than a hub. When it receives a message, it checks who its addressed to and sends it to only that so they are more secure. Therefore, it directs data packets to computers in a LAN. Router - correct answer An electronic device used to connect two or more networks. and usually to the Internet, by radio signals or wire. This allows data to be transferred from one network to the other. Uses of routers - correct answer Used to connect LANs together and to connect them to the internet Might be a wireless router and connect WLANs. Might link a LAN to a WAN (the internet) Bridge - correct answer A network device that typically links together two different parts of a LAN. It links independent parts of a LAN so they act as a single LAN Proxy Server - correct answer A type of server that acts as a buffer between a LAN and WAN (the internet). Acts like a local web server as it can store web pages so that if the same page is requested by multiple users on the LAN then the stored copy (cached copy) is sent to those users rather than getting a fresh copy from the Internet (responds more quickly)
You become vulnerable to hackers and virus' can be spread, putting you computer at great risk - websites might contain malware There is a lot of useless information Much of the information is biased, misleading or has not been checked for accuracy. It is not regulated and offensive and illegal material exists. Intranet - correct answer A private network that provides similar services to the Internet. However, these services are only for the users of the intranet - they are private, not public. Information can only be accessed from the local network or by logging on from a wider network such as the Internet. Uses of Intranets - correct answer Viewing internal web pages (e.g. company calendars, etc.) Internal e-mail and instant-messaging between workers Sharing of internal documents A and DA of Intranet - correct answer A. An Intranet is free to use because it does not involve phone links. A. Information can be easily updated and shared inside a company or school. A. The web pages can be viewed using a standard web page browser. A. More of the information will be useful because it was created for particular users.
DA. Information cannot be shared outside the local network without logging onto the Intranet What is needed to set up a small network? - correct answer One or more switches / hubs - to link devices together Network cables to connect devices to the switch, etc. A separate wireless access point (or this could be part of the switch) - to allow wireless devices to join the network A router to connect your LAN to the Internet (WAN) A firewall to protect your network from hackers Possibly a bridge if you already have a section of network and you want your new network to connect to it Server(s) to manage network functions such as network security, network file storage, shared resources (such as printers) Why is a browser needed to connect to the internet? - correct answer Needed to locate, retrieve and also display content on the World Wide Web, including Web pages, images, video and other files. Why is an e-mail needed for access to internet? - correct answer Enables users to send electronic mail to those outside the network. Companies use of e-mail because it is fast, flexible, and reliable and is needed to send messages to those outside the network. What is the need for an ISP? - correct answer Internet Service Providers provide people/companies with access to the internet and may provide Internet E-Mail accounts to users, which allow them to communicate with
DA. Password can be forgotten Biometric tests and magnetic chip cards with PIN - correct answer A. each user has unique biometrics that can't be changed A. Hacker needs to have the card and know the PIN DA. equipment is expensive to buy/may be difficult or expensive to get equipment to user. DA. can lose the card/can forget PIN What is the need for encryption, authentication techniques, User identification and passwords? - correct answer Protect your computer from damage or from hackers (people who gain access to computers and then illegally steal data) Encryption - correct answer Converting meaningful data into a form that cannot be understood by an unauthorised person When is encryption used? - correct answer When transferring private data over a network. At the recieving end if the user has the required key the unreadable text is decrypted into readable text again. Firewall - correct answer Blocks certain types of network traffic. Works in both directions, preventing unauthorised traffic from being sent out onto the network or from being sent to the computer from the network.
Fax - correct answer A fax machine is a device that can send a copy of a paper document over the telephone network E-mail - correct answer A system that allows messages to be sent and received by computers and can even send attachments. Video conferencing - correct answer A system that allows people to have conversations and meetings with other people in different locations, but without leaving their office through the use of a webcam, screen, speakers and microphone. Advantages of video conferencing - correct answer No travel costs No time wasted travelling to other cities / countries Can organise meetings at short notice Can see people as well as hear them Everyone can view a document on screen at the same time Disadvantages of video conferencing - correct answer Possibility of hardware breaking down Internet connection may become unstable Requires fast internet connection No substitute for face-to-face meeting
