Two Or More Computers Connected Together

3.3 Networks

1. Define networks

Two or more computers connected together.

2. Outline the advantages and disadvantages of networks

- Advantages:

- Easy sharing of data

- Centralized management of software

- Easier system maintenance

- Disadvantages:

- Security

- Control

- Intellectual property

3. Define client – server – hosts

- Client: computer that request the service from the server. (Ex. PC in school lab, PC at home, your smart phone)

- Server: computer that respond to clients’ requests.(Ex. Google Server, School server)

- Hosts: server/client

4. Describe the different types of servers

- Mail server

- Web server

- Video server

- Database server

5. Describe networks topologies(organization)

- star topology - Ring topology

- Bus topology

- Mish/Redundant topology

6. Explain grid computing or distributed processing

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.

7. Define Ethernet

It is a way to connect a computer to a network. It relies on copper wires for transmitting data.

8. Compare b/w client-server and peer-to-peer networks

Client-server P2P Centralized Decentralized Contains server No Server One Powerful computer and All computers have the same many clients power

9. State the advantages and disadvantages of P2P network.

 Advantages:

- Simple network

- No need for network administrator

- Easy data sharing

 Disadvantages:

- Difficult administration - Lack of security

10. Describe LAN at home components.

LAN: Local Area Network

Components:

- Router: to rout the signals to the computers in LAN

- Network cables: Copper, Twisted, Fiber optics, Bluetooth, WiFi.

- Modem: hardware to change analogue signals to digital and vice versa.

- Network card: Ethernet card

11. Define VLAN.

VLAN: Virtual LAN is a software solution that divides up a computer network into several subnetworks.

12. Define Internet

Internet (International Network) is the network of all computer networks around the world.

13. Define ARPANET

The first network, launched in 1969, university of California was connected to university of Stanford.

14. Identify Intranet

Network that belongs to a particular organization. ( Ex. School network,…)

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.

16. Define VPN

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)

17. Describe Hubs – Switches – Routers.

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

Switches: More intelligent than hubs, send data only for the computer intended.

Routers: The most complex, routs the data to the computer intended and know the IP address for the sender and receiver computers.

18. Define ISP

ISP: Internet Service Providers, the company that supplies a connection to the Internet (Ex. Batelco, Zain,...)

19. Outline the possible technologies that may be used to connect to the Internet.

- TV cables: very fast connection

- ADSL (Asynchronous Digital Subscriber Line): send digital signals through telephone lines

- Analogue dial-up: Connecting telephone line to computer modem directly

- Fiber Optics: signals are transmitted using light over glass fiber optic cables. Very fast. - Wireless (WiFi): no cables needed.

- Mobile phone network: WiFi for mobiles (Smart phones)

- ISDN (integrated services digital networks): faster than dial-up

- WiMax (Worldwide interoperability for Microwave access): WiFi to cover larger geographic regions.

20. Describe the connection methods that can be used to set up a LAN

- Ethernet: wired network

- WLAN (Wireless LAN) for long distance

- Bluetooth: wireless for short distance.

21. Define NOS

NOS (Network Operating System) operating systems that specifically designed to operate and manage computer networks.

22. State the main features for NOS:

- User Management

- Permission management

- Allows data access

- Allows hardware access

- Data security

- Backup

- Remote access

23. Define RAID system

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.

24. Define Protocols.

Protocols are agreements or standards on how data is to be exchanged over a network.

25. State the protocol’s responsibilities

26. Describe the common protocols.

- TCP/IP (Transmission Control Protocol/Internet Protocol) used by the internet.

- HTTP (Hyper Text Transfer Protocol): specifies how WebPages should be transferred.

- HTTPS (Secured HTTP): Uses encryption to make data more secure.

- POP3 (Post Office Protocol 3): used when receiving e- mail.

- FTP (File Transfer Protocol): used for uploading and downloading files.

27. Construct and Describe networks layers: 28. Describe Synchronous and Asynchronous communication.

Synchronous: both sender and receiver are online. Ex. (telephone call, chatting, video conferences)

Asynchronous: one of both parties (sender or receiver) online. Ex. (SMS, forums, E-mail)

29. Define remote access.

Using your computer to access another computer over a network.

30. Outline the two types of remote access.

- Accessing the files on another computer

- Accessing the desktop of a computer.

31. Describe bit rate.

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)

32. Define bandwidth, Broadband

Bandwidth: amount of data that can be transferred per unit of time.

Broadband: Network connection with large bandwidth.

33. State the cases where large bandwidth is necessary. - When downloading large media files

- For internet telephony such as VoIP (Voice over IP)

- For watching internet TV (IPTV)

- For websites that extensively use high resolution pixel graphics.

- When several computers share a common line.

34. Define Network Administrator

Sysadmin is a person who is responsible for ensuring that the LAN is working efficiently and smoothly.

35. Outline the tasks for sysadmin

- Upgrading and updating the software on the network

- Registering user accounts

- Setting up the permissions of the users

- Connecting and removing hardware of the LAN

- Giving advice and support to the users.

- Informing the administration about who violates network policies.

36. Define encryption and decryption.

- Encryption: is a method of making information unreadable to other people

- Decryption: is converting the information back into readable form.

37. State some applications for encryption

- Billing information

- VoIP - Individual files.

- E-mails

- Private information

38. Explain SSL and TLS

- SSL: Secure Socket Layer

- TLS: Transport Layer Security

Both are encryption methods that are commonly used to encrypt websites. They are used in E-commerce. They use https:// instead of http://

39. Outline the steps of network authentication

- Switch on your PC

- Enter login and password combination

- The server compares the combination with database

- If combination matches, the server will give you the access

- If combination is incorrect, access will not be given.

40. Define Password

Password is a secret combination of characters that is used to authenticate a user.

41. Outline the guidelines for strong passwords.

- Hard to guess

- Long enough

- Change periodically

- Use complex (upper-case, lower-case and special characters).

- Keep your login name secret. Example for simple password: naseem123

Example for complex password: N@seem_123

42. Define access level in networking

The permissions that determine the freedom that a user has when dealing with the files stored on the computer or the network.

43. Describe the security problems in networking

- Hacking: the attempt to gain illegal access to a computer system over a network.

- Denial of Service(DoS): send many requests to the server to make the server slow and overloaded.

- Phreaking: manipulation of telephone lines to gain illegal access.

- Phishing: spying of user’s personal data.

- Cracking: removing the copy protection of a piece of software.

- Malware: computer programs that are designed to do something harmful.

44. Outline the different security measures that can be used to secure networks.

- Login/password

- Biometrics

- Physical access control - Encryption

- Firewalls

45. Define firewall

Firewall is a computer with software that protects a LAN from the WAN.

46. Outline the common firewall features:

- Allows certain data packets to pass

- Allows trusted websites to pass

- Allows trusted e-mail to be accessed.

- Prevents the direct access to the HD from the WAN

- Filters the data that passes into the LAN

- Protects the LAN from unauthorized access.

47. State the reasons that cause network failing

- Network overload

- Viruses and worms

- HD failure

48. Define proxy server.

A computer that acts as an intermediary b/w the user’s computer and the internet.

49. State the main advantages for proxy servers.

- Hide IP address

- Increase efficiency

- View blocked websites - Increase security

50. Describe the licensing models for network software.

- Single user: one person

- Multi-users: for specified number of users.

- Concurrent license: central server

- Network license: for the whole LAN

- Site license: unlimited.

51. Outline the ways that could be used to monitor user behavior on a network.

- keystroke monitoring software (key loggers)

- system performance monitor

- Surveillance software.

52. Define packet sniffer.

Program that monitors the data packets that pass over the network then decodes and analyses the packets.

53. Define network policy

A formal, organization-internal specification on how networks are to be used properly.

54. State some network policy rules.

- Backup issues

- Archiving

- Disaster recovery

- Network usage - Redundancy specifications

- Failover

55. State the ACM code of ethics.

ACM: Association of Computing Machinery.

56. Define UPS

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.

57. Explain the possible ethical issues related to networks.

11E- TEST - Wed, 20-3-2013

11M- TEST - Wed, 20-3-2013

ALL NETOWKS – Case Study