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9. CHAPTER. COMMUNICATIONS AND NETWORKS. Competencies (Page 1 of 2). Discuss connectivity, the wireless revolution, and communication systems Describe physical and wireless communications channels Discuss connection devices, including modems, T1, DSL, cable modem, and satellite connections
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9 CHAPTER COMMUNICATIONS AND NETWORKS
Competencies (Page 1 of 2) • Discuss connectivity, the wireless revolution, and communication systems • Describe physical and wireless communications channels • Discuss connection devices, including modems, T1, DSL, cable modem, and satellite connections • Describe data transmission factors, including bandwidths and protocols • Discuss network and key network terminology Page 238
Competencies (Page 2 of 2) • Describe different types of networks, including local area, metropolitan area, and wide area networks • Describe network architectures, including configurations and strategies • Describe organizational uses of Internet technologies, including intranets, extranets, and firewalls Page 238
Communications The process of sharing data, programs, and information between two or more computers Page 240
Communications Today • Numerous applications depend on communication systems—E-mail, Instant messaging (IM), Internet telephone, and Electronic commerce • Connectivity uses computer networks to link people and resources • Going wireless has been the most dramatic change Page 240
Communication Systems • Four basic elements • Sending and receiving devices • Communication channel • Connection devices • Data transmission specifications Page 241
Communication Channels • Channels carry data from one computer to another • Two categories of communication channels • Physical connection • Wireless connection Page 242
Connection Device Signals • Types of signals • Analog • Digital Page 244
Connection Device Types • Types of modems • External • Internal • PC Card • Wireless Page 244
Connection Services • Dial-Up services • Leased lines – T1, T2, T3 and T4 • Digital subscriber line (DSL) • Uses existing phone lines • One type widely used is ADSL • Cable modems • Uses existing TV cable • Provides speeds as fast as DSL at a lower cost • Satellite/air connection services • Seven times faster than dial-up • Slower than DSL & cable modem Page 245
Bandwidth • Measurement of the capacity of the channel • Categories • Lowbandwidths or Voiceband • Medium band • Broadband • Used for high capacity transmission • Used by DSL, cable, and satellite Page 246
Protocols • Set of communication rules • Standard for Internet: TCP/IP (Transmission control protocol/Internet protocol) • Identifies devices • Reformats information Page 247
Networks • A computer network is a communication system • Connects two or more computers • Allows information exchange Page 247
Node Client Server Hub Network interface cards (NIC) Network operating system (NOS) Distributed processing Host computer Network manager Network Terms Computer Networks Connect Computers Page 248
Network Types • Local area networks • Home networks • WLAN • Metropolitan area networks • Wide area networks Page 249
Network Architecture • Architecture describes how a network is arranged • Arrangement is called topology • Types of network topology • Star • Bus • Ring • Hierarchical Page 251
Strategies • Strategy is a way of coordinating the sharing of information and resources • Common network strategies • Terminal • Client/server • Peer-to-peer Page 255
Internets and Extranets • Intranets • Private network within an organization • Provides information to employees • Extranets • Private network that connects organizations • Used to allow suppliers and others access • Firewalls • Security system • Protects against external threats Page 257
A Look to the FutureWireless Robotic Car • Pod car (Personalization on Demand) • Predicts and responds • Designed to learn and adapt to an individual's driving needs and habits Page 259
Discussion Questions • Define and discuss connectivity, the wireless revolution, and communications. • Identify and describe the various physical and wireless communication channels. • Identify the standard Internet protocol and discuss its essential features. • Define and discuss the four principal network topologies. • Define and discuss the three most common network strategies. Page 266