1. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill Chapter 09: Communications and Networks

2. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-2 McGraw-Hill Introduction We live in a truly connected society.We live in a truly connected society. Increased connectivity potentially means increased productivity, especially in business.Increased connectivity potentially means increased productivity, especially in business. You will learn more about the concept of connectivity and the impact of the wireless revolution in this chapter.You will learn more about the concept of connectivity and the impact of the wireless revolution in this chapter.

3. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-3 McGraw-Hill Communications Computer communications is the process of sharing data, programs, and information between two or more computersComputer communications is the process of sharing data, programs, and information between two or more computers Numerous applications depend on communication systems, includingNumerous applications depend on communication systems, including –E-mail –Instant messaging –Internet telephone –Electronic commerce –Global positioning systems (GPS)

4. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-4 McGraw-Hill Communications Today Connectivity uses computer networks to link people and resourcesConnectivity uses computer networks to link people and resources The Wireless RevolutionThe Wireless Revolution –Single most dramatic change in connectivity and communications has been widespread use of mobile telephones with wireless Internet connectivity

5. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-5 McGraw-Hill Communication Systems Four basic elementsFour basic elements –Sending and receiving devices –Communication channel –Connection devices –Data transmission specifications

6. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-6 McGraw-Hill Communication Channels Communication channels carry the data from one computer to anotherCommunication channels carry the data from one computer to another Two categories of communication channelsTwo categories of communication channels –Physical connection Physical connectionPhysical connection –Wireless connection Wireless connectionWireless connection

7. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-7 McGraw-Hill Physical Connections Ethernet cableEthernet cable (Twisted pair cable) Coaxial cableCoaxial cable Fiber-optic cableFiber-optic cable Return

8. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-8 McGraw-Hill Wireless Connections Return Radio frequency (RF)Radio frequency (RF) –Wi-Fi (wireless fidelity) –Bluetooth (short-range) –WiMax (extends Wi-Fi) MicrowaveMicrowave SatelliteSatellite –Global positioning system (GPS) InfraredInfrared –Short distances and line of sight

9. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-9 McGraw-Hill Communication Channels Summary

10. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-10 McGraw-Hill Connection Device Signals Types of signalsTypes of signals –Analog –Digital

11. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-11 McGraw-Hill Connection Devices Types of modemsTypes of modems 1.Dial Up Services 2.Telephone modem 3.DSL (digital subscriber line) 4.Cable modem 5.Wireless modem (WWAN)

12. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-12 McGraw-Hill Connection Services Dial-Up servicesDial-Up services –Uses phone lines Leased lines – T1Leased lines – T1 –Faster T3 and DS3 –Replaced by optical carrier (OC) lines Digital subscriber line (DSL)Digital subscriber line (DSL) –Uses phone lines –ADSL is most widely used type of DSL CableCable –Uses existing TV cable –Speeds as fast as DSL Satellite connection servicesSatellite connection services –Use almost anywhere –Slower than DSL and cable modem Cellular ServicesCellular Services –Use 3G and 4G cellular network to provide wireless connectivity

13. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-13 McGraw-Hill Typical user connection costs, bandwidth speeds, and comparable time required to download an imageTypical user connection costs, bandwidth speeds, and comparable time required to download an image Connection Costs and Speeds

14. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-14 McGraw-Hill Bandwidth Measurement of the width or capacity of the communication channelMeasurement of the width or capacity of the communication channel CategoriesCategories –Voice band (or low bandwidth) –Medium band –Broadband –Baseband

15. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-15 McGraw-Hill Protocols Communication rules for exchanging data between computersCommunication rules for exchanging data between computers Internet standard: TCP/IP (Transmission control protocol/Internet protocol)Internet standard: TCP/IP (Transmission control protocol/Internet protocol) –Identification – unique IP address –Packetization – broken down and reassembled

16. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-16 McGraw-Hill Networks A computer network is a communication system that connects two or more computersA computer network is a communication system that connects two or more computers Allows exchange of information and resourcesAllows exchange of information and resources

17. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-17 McGraw-Hill Computer Networks NodeNode ClientClient ServerServer Directory serverDirectory server HostHost SwitchSwitch Network interface cards (NIC)Network interface cards (NIC) Network operating systems (NOS)Network operating systems (NOS) Network administratorNetwork administrator

18. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-18 McGraw-Hill Network Types Local area network (LAN)Local area network (LAN) Home networkHome network Wireless LAN (WLAN)Wireless LAN (WLAN) Personal area network (PAN)Personal area network (PAN) Metropolitan area network (MAN)Metropolitan area network (MAN) Wide area network (WAN)Wide area network (WAN)

19. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-19 McGraw-Hill Network Architecture Arrangement is called topologyArrangement is called topology Types of network topologyTypes of network topology –Legacy BusBusBus RingRingRing –Current StarStarStar TreeTreeTree HybridHybridHybrid MeshMeshMesh

20. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-20 McGraw-Hill Bus Network Each device is connected to a common cable, called a bus or backboneEach device is connected to a common cable, called a bus or backbone All communications travel along this busAll communications travel along this bus There is no host; messages are passed device-to- device in a sequenceThere is no host; messages are passed device-to- device in a sequence Return

21. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-21 McGraw-Hill Ring Network Each device is connected to two other devicesEach device is connected to two other devices No central file server or computerNo central file server or computer Useful in a decentralized environmentUseful in a decentralized environment Return

22. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-22 McGraw-Hill Star Network Most widely used network topology for both homes and large businessesMost widely used network topology for both homes and large businesses Each device connects directly to a central network switchEach device connects directly to a central network switch Return

23. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-23 McGraw-Hill Tree Network Each device is connected to a central node, either directly or through subordinate nodesEach device is connected to a central node, either directly or through subordinate nodes Also known as a hierarchical networkAlso known as a hierarchical network Return

24. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-24 McGraw-Hill Hybrid Network Combination of different topologiesCombination of different topologies Large organizations have a complex network of smaller networksLarge organizations have a complex network of smaller networks –These smaller networks use a variety of configurations –When connected together, they form a hybrid Return

25. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-25 McGraw-Hill Mesh Network Does not use a specific physical layout, but requires that each node have more than one connection to other nodesDoes not use a specific physical layout, but requires that each node have more than one connection to other nodes Wireless technologies are frequently usedWireless technologies are frequently used Return

26. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-26 McGraw-Hill Network Topologies

27. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-27 McGraw-Hill Network Strategies Terminal server networkTerminal server network Client/server networkClient/server network Peer-to-peer (P2P) networkPeer-to-peer (P2P) network Distributed processing networkDistributed processing network Terminal ServerPeer-to-PeerClient/Server

28. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-28 McGraw-Hill Organizational Networks Organizational Networks IntranetsIntranets –Private network within an organization –Works like the Internet, where employees use browsers to access Web sites and Web pages ExtranetsExtranets –Private network that connects organizations –Works like the Internet, but provides suppliers and other trusted partners with limited access to the organization’s networks

29. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-29 McGraw-Hill Network Security FirewallsFirewalls –Combination of hardware and software –Proxy server provides pass-through access –Protects against external threats Intrusion detection systems (NIDS)Intrusion detection systems (NIDS) Virtual private networks (VPN)Virtual private networks (VPN) –Creates a secure private network connection between your computer and the organization

30. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-30 McGraw-Hill Careers In IT Network AdministratorNetwork Administrator –Manages a company’s LAN and WAN networks –Maintains networking hardware and software, diagnosing and repairing problems that arise –Candidates usually have a bachelor’s degree in computer science and practical experience –Annual salary is typically between $48,500 and $79,000

31. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-31 McGraw-Hill A Look to the Future Telepresence Lets You Be There without Actually Being ThereTelepresence Lets You Be There without Actually Being There –Seeks to create the illusion that you are actually at a remote location –Early implementations mainly focus on an extension of video-conferencing

32. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-32 McGraw-Hill Open-Ended Questions (1 of 2) Define and discuss connectivity, the wireless revolution, and communications.Define and discuss connectivity, the wireless revolution, and communications. Identify and describe the various physical and wireless communication channels.Identify and describe the various physical and wireless communication channels. Identify the standard Internet protocol and discuss its essential features.Identify the standard Internet protocol and discuss its essential features.

33. Copyright © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Computing Essentials 2012: Making IT Work for You 9-33 McGraw-Hill Open-Ended Questions (2 of 2) Discuss past and present network topologies.Discuss past and present network topologies. Define and discuss four common network strategies.Define and discuss four common network strategies.