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Transcript
Test your knowledge Chapter 7 theory Page 240 Questions 13 – 31 13. Why do manufacturers of network hardware and software follow established standards? They establish these standards because it will avoid problems associated with incompatibility between hardware and software components, organisations such as the Institution of Electrical and Electronics Engineers develop network standards. 14. Briefly describe how an Ethernet network transmits data. They use cables to transfer data across. The original Ethernet standard is not very fast by today’s standards. A second Ethernet standard is called Fast Ethernet. They transfer data at speeds of 100Mbps, up to 10 times faster than the original. They allow personal computers to contend for access to the network. If two computers try to send data via Ethernet they will collide and must attempt to send again. 15. In what situations would TCP/IP protocol be most useful? It manages the transmission of data by breaking it up into packets and transmitting the packets over the Internet. An important part is the IP address. The IP addressing standard defines a mechanism to provide a unique address for each computer on the Internet. 16. Explain the term ‘packet switching’. Packet switching is a technique of breaking a message into individual packets, sending the packets along the best route available, and then reassembling the data. 17. What network transmission standard would be useful in a situation where an old, heritage-listed building with solid stone walls needs to be networked? The 802.11 standard would be best useful in old buildings. 18. Describe how verifying the identity of a user can protect a network? A username also known as user ID, is a unique combination of characters, such as letters or numbers. By typing this in, it gives the identity on one specific user. Then a password will be asked that is a secret combination of characters. Most network operation systems require these combinations correctly before you access the data. 19. What is a firewall? A firewall is a general term that refers to hardware or software that restricts access to data and information on a network. One use of firewalls is to deny network access to outsiders. 20. Describe three measures that should be incorporated into a wireless network to restrict access by unauthorised users and to secure the transmission of data. To avoid unauthorised network access, should include firewall. The recommended security ways should include: The wireless access point should be configured so that it does not broadcast a network name. It should also allow access only to specified devices. Use Wireless Equivalent Privacy, which is a standard that defines how to encrypt data as it travels across wireless networks. 21. Some communications software support file transfer protocol (FTP). What is the purpose of FTP? FTP is an Internet standard that allows you to upload and download files to and from a webserver, called FTP server. To view or use a file on an FTP server, you can download the file from the server to your computer. 22. What is the purpose of a network interface card? A network interface card is a card you insert into an expansion slot of a personal computer or other device, such as a printer, enabling the device to connect to a network. 23. A wireless access point can be wired to the fibre optic backbone of a bus network. What is the purpose of the wireless access point? The purpose of a wireless access point is a device that allows computers and devices such as printers to transmit data wires sly among themselves. They are normally placed near the ceiling. 24. Routers and switches are used to connect separate networks. Explain the circumstances in which each of these would be used. A router will connect LANs irrespective of the hardware and network communications protocol used in each LAN segment. A switch stores the address of every device down each cable connected to it. When a packet enters the switch, it uses simple logic to detect the destination of a packet and sends the packet only down the cable that contains the addressed device. 25. What is the difference between baseband and broadband transmission? A baseband transmission can only transmit only one single at a time whereas broadband transmission can transmit multiple signals simultaneously. 26. What is the advantage of using coaxial cable over twisted-pair wire? When would you use twistedpair? Twisted-pair wire is used for telephone systems. Coaxial cable is used for cable television. It can be cabled over longer distances that twisted-pair cable can. 27. What advantages does fibre optics have over wire cables? The advantages fibre optic cables have over wire cables is; The capability of carrying significantly more signals that wire cables Faster data transmission Less susceptibility to noise from other devices Better security for signals during transmission Their smaller size (much thinner and lighter) 28. In what circumstances would a network designer consider using wireless transmission media? They would use it when they want to do broadcast radio, cellular radio, microwaves, communications satellites and infra-red. 29. Briefly describe the broadcast radio and cellular radio wireless transmission data. Broadcast radio is a wireless transmission medium that distributes radio signals through the air over long distances and short distances. Cellular radio is a form of broadcast radio that is used widely for mobile communications, specifically wireless modems and mobile phones. 30. What is the main limitation of microwave transmission? The main limitation for microwave transmission is it must transmit in a straight line with no obstructions between microwave antennas. 31. Many companies use satellite transmission to access the Internet. Web satellites, however, will provide faster downlink transmission that uplink transmissions. Why is the difference in speed not of major concern to these companies? With satellite Internet connections, the uplink transmission are usually slower than the downlink transmissions. The difference in speeds is usually acceptable to most Internet satellite users because they download much more data that they upload. 32. Describe the advantages of setting up a home network. The advantages of having a home network are, all the computers in the house can be connected to the Internet at the same time. Each computer can access files and programs on the other computers in the home. All computers can share the one printer or DVD drive. Each networked computer is able to play multiplayer video games with other computers. 33. There are four types of home network in common use. Which type would you choose to set up a network in your home? Why would you choose that type? A Wi-Fi network. I would choose a Wi-Fi network because I have three computers in my home. The main computer has a cable connected to it via the router. The router is wireless which gives radio waves which signals the other two computers to have access to the Internet without any wires or cables connected to those computers. 34. Identify the four elements of a data flow diagram. A data flow diagram has four main elements, these are; Processes, represented by circles Data stores, drawn as pairs of parallel lines Data flows, indicated by arrows, and Sources or entities, drawn as squares