1. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Extended Learning Module E Network Basics

2. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin STUDENT LEARNING OUTCOMES 1. Identify and describe the four basic concepts on which networks are built and describe what is needed to set up a small peer-to-peer network at home.

3. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin STUDENT LEARNING OUTCOMES 3. Describe the components used to build large business networks and define and compare local area networks (LANs), wide area networks (WANs), and metropolitan area networks (MANs). 4. Compare and contrast the various Internet connection possibilities.

4. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin STUDENT LEARNING OUTCOMES 5. Compare and contrast the types of communications media. 6. State the four principles of computer security and describe how different network security devices reflect those principles.

5. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin INTRODUCTION  Computer network – two or more computers connected so that they can communicate with each other and share information, software, peripheral devices, and/or processing power

6. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin INTRODUCTION

7. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Basic Principles of Networks  Four main principles 1. Each computer must have a network interface to provide a doorway for information 2. The network usually has at least one connecting device 3. The network must have communications media to transport information

8. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Basic Principles of Networks 4. Each computer must have software to move information in and out of the computer  These four principles apply to all networks, large and small

9. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin HOME NETWORKS  A typical home network setup has 1. An Ethernet network card in each computer or a wireless card in each laptop 2. Network cables to transmit signals, or radio waves for wireless 3. A DSL or cable modem connection and a broadband/home router

10. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Network Cards  Network interface card (NIC) – an expansion card or PC card that connects your computer to a network  Ethernet card – the most common type of network interface card  Built into the motherboards of many new computers

11. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Wired Transmission Media  Cat 5 (Category 5) cable – better- constructed version of phone twisted-pair cable

12. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Wireless Transmission Media  Wireless Access Point (WAP) – device that allows a computer to use radio waves to access a network  Connects to switch with a cable like a wired computer  May be built into broadband router and not require separate cabling

13. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Home Internet Service  Broadband router or home router – a device to connect computers together to share DSL or cable Internet service in a home or small office  One port to plug into DSL or cable connection to connect to the Internet  Usually several ports to build a network for home computers or printers and share Internet connection

14. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Network Software  Makes each computer's hardware work  Can use Windows  Turn on filesharing to make files available to other computers on the network

15. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin NETWORK COMPONENTS  Switch – a device that connects computers and repeats transmissions only to intended recipient  Multiple conversations can occur simultaneously between different sets of computers  Only recipient computer sees each message  Computers can still broadcast messages to all other computers on the network

16. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin NETWORK COMPONENTS  Router – a device that connects subnetworks (subnets) of a larger network  Can connect different buildings at same or different locations  Passes transmissions from one network to another  May pass through multiple routers on the way from source to destination

17. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin NETWORK COMPONENTS  More on routers  Home/broadband routers often have built-in switches  Corporate routers generally require separate switches  Routers must be configured with information about the networks they connect

18. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin NETWORKS BY DISTANCE  Large networks can be classified by the size of the area(s) they serve:  Local Area Network (LAN) – network that serves a building or buildings in a contiguous area

19. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin NETWORKS BY DISTANCE  More networks by distance  Wide Area Network (WAN) – a set of connected networks serving areas not immediately contiguous  Metropolitan Area Network (MAN) – a set of connected networks within the same city or metropolitan area but not in immediate proximity to each other

20. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin THE INTERNET  A vast network of computers that connects people all over the world  Computers pass messages through routers to their ultimate destinations  Each router determines whether it has a direct path to the recipient or whether to send the message on to another router

21. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Bandwidth  The amount of information that can be transferred in a given amount of time  Usually expressed as bits per second (bps)  Higher bandwidths expressed as  kilobits per second (Kbps) – thousands of bits per second  megabits per second (Mbps) – millions of bits per second  gigabits per second (Gbps) – billions of bits per second

22. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Internet Connection Types  Phone line and dialup modem  Phone line and DSL modem  Cable TV line and cable modem  Satellite modem  Dedicated high-speed business lines

23. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Broadband Internet Connection  Broadband – high-capacity telecommunications line capable of providing high-speed Internet service  All Internet access methods on the previous slide are broadband except the dialup modem

24. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Dialup Connection  Modem – connects a computer to a phone line to access another computer or network  Modulates outgoing signal from digital to analog form  Demodulates incoming signal from analog to digital form

25. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Digital Subscriber Line (DSL)  Digital Subscriber Line (DSL) – high- speed Internet connection using phone lines, which allows you to use your phone for voice communications at the same time  Runs at a higher frequency than voice conversations, so not supported on some older phone lines

26. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Cable Modem  Cable modem – uses your TV cable to deliver an Internet connection

27. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Satellite Modem  Satellite modem – delivers Internet access by means of a satellite dish  Satellite TV and modem may share same dish or may be separate  Connects to computer or broadband router like cable modem

28. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin T1 and DS3 Business Lines  T1 and DS3 developed by phone companies to carry many long- distance voice conversations  T1 runs up to about 1.5 Mbps  DS3 runs up to about 45 Mbps  Can carry both voice and network over the same lines

29. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Frame Relay and ATM Business Services  Frame Relay and ATM are used to connect many branch offices to the main office  Use virtual circuits to simulate having a line from every office to every other office Virtual Circuits

30. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Comparison of Connection Types  Telephone modem  + Inexpensive and available anywhere there's a phone line  - Slow, and ties up the line for voice calls too  DSL  + Higher-speed connection, doesn't tie up the phone line for voice calls, and can be left on all the time  - Not available in all areas or on all lines

31. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Comparison of Connection Types  Cable modem  + Higher-speed connection, doesn't use the phone line at all, and is always-on  - Connection shared with others in the neighborhood, so speed may vary  Satellite modem  + Available in remote locations where DSL and cable aren't  - High cost

32. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Comparison of Connection Types  T1 and DS3  + High-speed to very-high-speed connections, can transmit both voice and data  - High cost that may be mileage-dependent  Frame relay and ATM  + Use virtual circuits to simulate more inter- office connections than are physically present  - High cost normally affordable only by mid- to large-scale enterprises

33. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Voice Over IP  Voice over IP – allows you to send voice communications over the Internet and avoid long-distance toll charges  No long-distance calling cost

34. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin NETWORK COMMUNICATIONS MEDIA  Communications media – the paths in a network over which information travels  Wired communications media – transmit information over a closed, connected path  Wireless communications media – transmit information through the air

35. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Wired Communications Media  Twisted-pair cable – a bundle of copper wires for transmitting voice or data  Cat 5 and Cat 5e are common for modern networks  Coaxial cable (coax) – one central wire surrounded by insulation, a metallic shield, and a covering of insulation

36. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Wired Communications Media  Optical fiber – uses a very thin glass or plastic fiber through which pulses of light travel

37. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Wireless Communications Media  Infrared – uses red light to send and receive information  Wi-Fi or Wireless Fidelity - a standard for transmitting information in the form of radio waves over distances of about 100 feet  With directional antennas, the distance can be increased to several miles  Wi-Fi hotspots – sites that offer wireless Internet access for your laptop or tablet.

38. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Wireless Communications Media  Bluetooth – a standard for transmitting information in the form of short-range radio waves over distances of up to 30 feet and is used for purposes such as wirelessly connecting a cell phone to a computer

39. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Wireless Communications Media  Microwave – a type of radio transmission  Repeater – receives a radio signal, strengthens it, and sends it on  Satellite – microwave in space where the signal shoots up to a satellite above the earth and is reflected down again.

40. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Wireless Communications Media

41. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Wireless Communications Media  Communications Satellite – microwave repeater in space

42. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin NETWORK SECURITY  The four principles of network security are: 1. Confidentiality 2. Authenticity 3. Integrity 4. Availability

43. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin NETWORK SECURITY  Confidentiality – information can be obtained only by those authorized to access it  Bank statements, credit reports, employee evaluations  Threatened by capture of network transmissions and easily-guessed passwords

44. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin NETWORK SECURITY  Authenticity – information really comes from the source it claims to come from  Military orders, medical diagnoses, stockbroker directions  Threatened by fraudulent e-mails and misspellings of popular Web site names

45. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin NETWORK SECURITY  Integrity – information has not been altered  Bank balance, corporate Web site, prescriptions, credit card charges  Threatened by forged network transmissions and faulty server software

46. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin NETWORK SECURITY  Availability – a service or resource is available when it's supposed to be  Mail-order Web site, corporate e-mail server  Threatened by network failures, faulty server software, and high volumes of malicious network traffic

47. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Firewalls & Intrusion Detection Systems  Firewall – protects a computer from intruders  Intrusion detection system (IDS) – watches for and reports intrusion attempts  Intrusion prevention system (IPS) – type of IDS that also takes action against intrusion attempts

48. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Encryption  Encryption – scrambles data so you can't read it without having the decryption key  Virtual Private Network (VPN) – encrypts all network transmissions between two endpoints to protect confidentiality and integrity of data

49. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Firewalls & Intrusion Detection Systems

50. © McGraw-Hill Companies, Inc., McGraw-Hill/Irwin Malware  Malware – software designed to harm your computer or security 1. Virus – software written with malicious intent to cause annoyance or damage 2. Worm – spreads itself from computer to computer via e-mail and other network traffic 3. Spyware – collects information about you and reports it to someone else without your permission