<p>3.3 Networks</p><p>1. Define networks</p><p>Two or more computers connected together.</p><p>2. Outline the advantages and disadvantages of networks</p><p>- Advantages:</p><p>- Easy sharing of data</p><p>- Centralized management of software</p><p>- Easier system maintenance</p><p>- Disadvantages:</p><p>- Security</p><p>- Control</p><p>- Intellectual property</p><p>3. Define client – server – hosts</p><p>- Client: computer that request the service from the server. (Ex. PC in school lab, PC at home, your smart phone)</p><p>- Server: computer that respond to clients’ requests.(Ex. Google Server, School server)</p><p>- Hosts: server/client</p><p>4. Describe the different types of servers</p><p>- Mail server</p><p>- Web server</p><p>- Video server</p><p>- Database server</p><p>5. Describe networks topologies(organization)</p><p>- star topology - Ring topology</p><p>- Bus topology</p><p>- Mish/Redundant topology</p><p>-</p><p>6. Explain grid computing or distributed processing</p><p>Special software distributes the computation tasks over the network to the different computers. The computers then work on their assigned task in parallel and send back the results to a central server. </p><p>7. Define Ethernet</p><p>It is a way to connect a computer to a network. It relies on copper wires for transmitting data.</p><p>8. Compare b/w client-server and peer-to-peer networks</p><p>Client-server P2P Centralized Decentralized Contains server No Server One Powerful computer and All computers have the same many clients power</p><p>9. State the advantages and disadvantages of P2P network.</p><p> Advantages:</p><p>- Simple network</p><p>- No need for network administrator</p><p>- Easy data sharing</p><p> Disadvantages:</p><p>- Difficult administration - Lack of security</p><p>10. Describe LAN at home components.</p><p>LAN: Local Area Network</p><p>Components:</p><p>- Router: to rout the signals to the computers in LAN</p><p>- Network cables: Copper, Twisted, Fiber optics, Bluetooth, WiFi. </p><p>- Modem: hardware to change analogue signals to digital and vice versa.</p><p>- Network card: Ethernet card</p><p>11. Define VLAN.</p><p>VLAN: Virtual LAN is a software solution that divides up a computer network into several subnetworks.</p><p>12. Define Internet</p><p>Internet (International Network) is the network of all computer networks around the world.</p><p>13. Define ARPANET</p><p>The first network, launched in 1969, university of California was connected to university of Stanford.</p><p>14. Identify Intranet</p><p>Network that belongs to a particular organization. ( Ex. School network,…)</p><p>15. Identify Extranet Extension of Intranet, they allow business partners to access a part of the company’s Intranet for the purpose of data exchange.</p><p>16. Define VPN</p><p>Virtual Private Network used to encrypt the data sent over the network and make it appear as if the company owns private network (Security issue)</p><p>17. Describe Hubs – Switches – Routers.</p><p>Hubs: Hardware used to connect the computers in the network, has one input port and several output ports, it is the least intelligent. Distributes data to all computers in the network</p><p>Switches: More intelligent than hubs, send data only for the computer intended.</p><p>Routers: The most complex, routs the data to the computer intended and know the IP address for the sender and receiver computers.</p><p>18. Define ISP</p><p>ISP: Internet Service Providers, the company that supplies a connection to the Internet (Ex. Batelco, Zain,...)</p><p>19. Outline the possible technologies that may be used to connect to the Internet.</p><p>- TV cables: very fast connection</p><p>- ADSL (Asynchronous Digital Subscriber Line): send digital signals through telephone lines</p><p>- Analogue dial-up: Connecting telephone line to computer modem directly </p><p>- Fiber Optics: signals are transmitted using light over glass fiber optic cables. Very fast. - Wireless (WiFi): no cables needed.</p><p>- Mobile phone network: WiFi for mobiles (Smart phones)</p><p>- ISDN (integrated services digital networks): faster than dial-up</p><p>- WiMax (Worldwide interoperability for Microwave access): WiFi to cover larger geographic regions.</p><p>20. Describe the connection methods that can be used to set up a LAN</p><p>- Ethernet: wired network</p><p>- WLAN (Wireless LAN) for long distance</p><p>- Bluetooth: wireless for short distance.</p><p>21. Define NOS</p><p>NOS (Network Operating System) operating systems that specifically designed to operate and manage computer networks.</p><p>22. State the main features for NOS:</p><p>- User Management</p><p>- Permission management</p><p>- Allows data access</p><p>- Allows hardware access</p><p>- Data security</p><p>- Backup</p><p>- Remote access</p><p>23. Define RAID system</p><p>RAID (Redundant Array of Inexpensive Disks) is an assembly of several inexpensive hard disk drives connected together to reduce the risk of data loss in case of disk failure.</p><p>24. Define Protocols.</p><p>Protocols are agreements or standards on how data is to be exchanged over a network. </p><p>25. State the protocol’s responsibilities</p><p>Page 104</p><p>26. Describe the common protocols.</p><p>- TCP/IP (Transmission Control Protocol/Internet Protocol) used by the internet.</p><p>- HTTP (Hyper Text Transfer Protocol): specifies how WebPages should be transferred.</p><p>- HTTPS (Secured HTTP): Uses encryption to make data more secure.</p><p>- POP3 (Post Office Protocol 3): used when receiving e- mail.</p><p>- FTP (File Transfer Protocol): used for uploading and downloading files.</p><p>27. Construct and Describe networks layers: 28. Describe Synchronous and Asynchronous communication.</p><p>Synchronous: both sender and receiver are online. Ex. (telephone call, chatting, video conferences)</p><p>Asynchronous: one of both parties (sender or receiver) online. Ex. (SMS, forums, E-mail)</p><p>29. Define remote access.</p><p>Using your computer to access another computer over a network.</p><p>30. Outline the two types of remote access.</p><p>- Accessing the files on another computer</p><p>- Accessing the desktop of a computer.</p><p>31. Describe bit rate.</p><p>A measure of transmission speed of data over a telecommunication line. It measures how many bits can be transmitted in 1 second. Ex. (512 bps, 54 kbps, 1000 mbps)</p><p>32. Define bandwidth, Broadband</p><p>Bandwidth: amount of data that can be transferred per unit of time. </p><p>Broadband: Network connection with large bandwidth.</p><p>33. State the cases where large bandwidth is necessary. - When downloading large media files</p><p>- For internet telephony such as VoIP (Voice over IP)</p><p>- For watching internet TV (IPTV)</p><p>- For websites that extensively use high resolution pixel graphics.</p><p>- When several computers share a common line.</p><p>-</p><p>34. Define Network Administrator</p><p>Sysadmin is a person who is responsible for ensuring that the LAN is working efficiently and smoothly. </p><p>35. Outline the tasks for sysadmin</p><p>- Upgrading and updating the software on the network</p><p>- Registering user accounts</p><p>- Setting up the permissions of the users</p><p>- Connecting and removing hardware of the LAN</p><p>- Giving advice and support to the users.</p><p>- Informing the administration about who violates network policies.</p><p>36. Define encryption and decryption.</p><p>- Encryption: is a method of making information unreadable to other people</p><p>- Decryption: is converting the information back into readable form.</p><p>37. State some applications for encryption</p><p>- Billing information</p><p>- VoIP - Individual files.</p><p>- E-mails</p><p>- Private information</p><p>38. Explain SSL and TLS</p><p>- SSL: Secure Socket Layer</p><p>- TLS: Transport Layer Security</p><p>Both are encryption methods that are commonly used to encrypt websites. They are used in E-commerce. They use https:// instead of http://</p><p>39. Outline the steps of network authentication</p><p>- Switch on your PC</p><p>- Enter login and password combination</p><p>- The server compares the combination with database</p><p>- If combination matches, the server will give you the access</p><p>- If combination is incorrect, access will not be given. </p><p>40. Define Password</p><p>Password is a secret combination of characters that is used to authenticate a user.</p><p>41. Outline the guidelines for strong passwords.</p><p>- Hard to guess</p><p>- Long enough</p><p>- Change periodically</p><p>- Use complex (upper-case, lower-case and special characters).</p><p>- Keep your login name secret. Example for simple password: naseem123</p><p>Example for complex password: N@seem_123</p><p>42. Define access level in networking</p><p>The permissions that determine the freedom that a user has when dealing with the files stored on the computer or the network.</p><p>43. Describe the security problems in networking</p><p>- Hacking: the attempt to gain illegal access to a computer system over a network.</p><p>- Denial of Service(DoS): send many requests to the server to make the server slow and overloaded.</p><p>- Phreaking: manipulation of telephone lines to gain illegal access.</p><p>- Phishing: spying of user’s personal data.</p><p>- Cracking: removing the copy protection of a piece of software.</p><p>- Malware: computer programs that are designed to do something harmful.</p><p>44. Outline the different security measures that can be used to secure networks.</p><p>- Login/password</p><p>- Biometrics</p><p>- Physical access control - Encryption</p><p>- Firewalls</p><p>45. Define firewall</p><p>Firewall is a computer with software that protects a LAN from the WAN.</p><p>46. Outline the common firewall features:</p><p>- Allows certain data packets to pass</p><p>- Allows trusted websites to pass</p><p>- Allows trusted e-mail to be accessed.</p><p>- Prevents the direct access to the HD from the WAN</p><p>- Filters the data that passes into the LAN</p><p>- Protects the LAN from unauthorized access.</p><p>47. State the reasons that cause network failing</p><p>- Network overload</p><p>- Viruses and worms</p><p>- HD failure</p><p>48. Define proxy server.</p><p>A computer that acts as an intermediary b/w the user’s computer and the internet.</p><p>49. State the main advantages for proxy servers.</p><p>- Hide IP address</p><p>- Increase efficiency</p><p>- View blocked websites - Increase security</p><p>50. Describe the licensing models for network software.</p><p>- Single user: one person</p><p>- Multi-users: for specified number of users.</p><p>- Concurrent license: central server</p><p>- Network license: for the whole LAN</p><p>- Site license: unlimited.</p><p>51. Outline the ways that could be used to monitor user behavior on a network.</p><p>- keystroke monitoring software (key loggers)</p><p>- system performance monitor</p><p>- Surveillance software.</p><p>52. Define packet sniffer.</p><p>Program that monitors the data packets that pass over the network then decodes and analyses the packets.</p><p>53. Define network policy</p><p>A formal, organization-internal specification on how networks are to be used properly.</p><p>54. State some network policy rules.</p><p>- Backup issues</p><p>- Archiving</p><p>- Disaster recovery</p><p>- Network usage - Redundancy specifications</p><p>- Failover</p><p>55. State the ACM code of ethics.</p><p>ACM: Association of Computing Machinery.</p><p>Page 115.</p><p>56. Define UPS</p><p>UPS: Uninterruptible Power Supply, a piece of hardware that is connected to the server to keep the server running for several minutes when the power is off. </p><p>57. Explain the possible ethical issues related to networks.</p><p>Page 117.</p><p>11E- TEST - Wed, 20-3-2013</p><p>11M- TEST - Wed, 20-3-2013</p><p>ALL NETOWKS – Case Study</p>