Computer Networks Fundamentals

1. Computer Networks Fundamentals Morrison / Wells

2. Objectives • Describe a network. • Explain the benefits of a network. • Identify the risks of network computing. 2 2

3. Vocabulary • biometric security measures • cable modem • client • client/server network • communication channels • digital subscriber line (DSL) 3 3

4. Vocabulary • Describe the roles of clients and servers on a network. • List and describe the types of networks. • List and describe communications media and hardware. • Describe network security.

5. Vocabulary • extranet • firewall • hacker • hub • Internet • intranet • local area network (LAN) • modem

6. Vocabulary (continued) • node • peer-to-peer network • proxy server • Public Switched Telephone Network (PSTN) • router • server 6 6

7. Introduction • Connecting computers through a network, a group of two or more computers linked together, allows users to share software applications and to share hardware devices such as printers, scanners, and other hardware add-ons. 7 7

8. Introduction • server operating system • T-1 line • wide area network (WAN) • WiMAX-Worldwide Interoperability for Microwave Access • wireless Internet service provider • (WISP)-wirelessISP • wireless LAN (WLAN)

9. Use of networks • Companies and organizations use networks to connect employees and subsidiaries nationally and even internationally.

10. Introducing Networks • The Public Switched Telephone Network (PSTN) supports telephone service and is the world’s collection of interconnected commercial and government-owned voice-oriented systems. 10 10

11. Network Benefits • The biggest network of all is the Internet. Network benefits include: • Information sharing • Collaborative environment • Hardware sharing • Software sharing • Enhanced communications Information sharing 11 11

12. Client/Server Networks • The term client/server network describes a software architectural model relationship. • In most instances, the client is a software program such as Internet Explorer. The server is hardware and can be one of many types of servers, such as a mail server, a database server, an FTP server, an application server, or a Web server. 12 12

13. Risks of Networked Computing • As with any technology, disadvantages also exist. Disadvantages of networks include: • Individual loss of autonomy • Malicious code • Network faults • Setup and management costs • E-mail is not necessarily private 13 13

14. Network Os • Server operating systems are high-end programs designed to provide network control and include special functions for connecting computers and other devices into a network.

15. Network Types • Networks are divided into two main types: local area networks (LANs) and wide area networks (WANs). 15 15

16. Network Types (continued) • Wide Area Networks: • A WAN covers a large geographical area and can contain communication links across metropolitan, regional, or national boundaries. 16 16

17. Network Types (continued) • Local Area Networks: • Most LANs connect personal computers, workstations, and other devices such as printers and scanners in a limited geographical area. Wireless LAN 17

18. Network types include: • Client/server network: Server manages resources • Peer-to-peer network: All computers are equal • Intranet: Used within an organization • Extranet: Specific outside users can access • Internet: Global network allows worldwide connection

19. Communication Hardware: • Communication hardware devices facilitate the transmitting and receiving of data. Examples are: • Modem: Converts analog signals to digital and vice versa • Cable modem: Uses coaxial cable • Digital subscriber line: Uses ordinary phone lines • T-1: Type of fiber-optic telephone line • Wireless: Delivers fast connection speeds 19 19

20. Network Security Issues • Passwords are the most common form of restricting access to data. • Establishing and maintaining computer security is necessary to keep hardware, software, and data safe from harm or destruction. 20 20

21. Network Security Issues (continued) • Other security measures include: • Electronic identification cards • Firewalls to protect companies’ networks from external networks • Antivirus software • A proxy server that acts as an intermediary between a user and the Internet. 21 21

22. Network Security Issues (continued) • Planning for Security: • Companies must plan for security before it is needed • Institute a selective hiring process. • Regularly back up data and store it off site. • Employ biometric security measures. 22 22

23. Network Security • Wireless networking is very common, but has many security issues and hackers have found it very easy to access wireless networks. 23 23

24. Summary In this lesson, you learned: • A network is a group of two or more computers linked together. 24 24

25. Summary • A telephone network is similar in makeup to a computer network. The Public Switched Telephone Network (PSTN) supports telephone service, and it is the world’s largest collection of interconnected commercial and government-owned voice-oriented systems.

26. Summary (continued) • You can use a network for information sharing, hardware sharing, software sharing, and as a collaborative environment. • Networks are divided into two main types: local area networks and wide area networks. 26 26

27. summary • Local area networks (LANs) connect personal computers, workstations, and other devices such as printers and scanners in a limited geographical area, such as an office building, a school, or a home.

28. Summary (continued) • A wide area network (WAN) is made up of several connected local area networks. 28 28

29. Summary • In a client/server network, one or more computers on the network act as a server. The server manages network resources. In a peer-to-peer network, all of the computers are equal.

30. Summary (continued) • Data security is a risk with many networks. Some risks to computers are natural causes, some are accidents, and others are intentional. 30 30

31. Summary • The best way to protect data is to effectively control the access to it. Generally, this protection is the responsibility of the network administrators and security personnel.

32. Summary • If unauthorized persons gain access to data, they may obtain valuable information or trade secrets. Hackers are people who break into computer systems to steal services and information.

33. Summary (continued) • Transmission media can be either physical or wireless. • A modem is a type of communication device. A hub is a device that controls the incoming and forwarding of data. A router directs traffic on the Internet or on multiple connected networks. 33 33

34. Summary • No computer is designated as the server. People on the network each determine what files on their computer they share with others on the network.