99 CHAPTER COMMUNICATIONS AND NETWORKS

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved. 9-2 Competencies Discuss connectivity, the wireless revolution, and communication systems Describe physical and wireless communications channels Discuss connection devices Describe data transmission factors

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved. 9-3 Competencies cont. Discuss networks and key network terminology Describe the different types of networks Describe network architectures Describe organizational uses of Internet technologies

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved. 9-4 What is Communication? The process of sharing data, programs, and information between two or more computers

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved. 9-5 Communications Today

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved. 9-6 Communication Systems

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved. 9-7 Communication Channels Channels carry data from one computer to another Two categories of communication channels Physical connection Wireless connection

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved. 9-8 Physical Connections Telephone lines Coaxial cable Fiber-optic cable

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved. 9-9 Wireless Connections Infrared Broadcast radio Microwave Stations Bluetooth Satellite Uplink/Downlink Global Positioning System

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved More on Satellites Global positioning Network of 24 satellites Owned by the Defense Department Global positioning system (GPS) Devices used to determine location Provides navigational support

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Connection Devices Types of signals Analog Digital Types of modems Internal External PC Card Wireless

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Types of Connections Digital subscriber line (DSL) Uses existing phone lines ADSL (Asymmetric digital subscriber line) 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

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved User Connection Costs & Speeds TypeFeeSpeedSeconds to Get Images Dial-up$1656 kbps45.0 DSL mbps1.7 Cable Modem mbps1.7 Satellite kbps2.8

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Bandwidth Measurement of the capacity of the channel Categories Low bandwidths or Voiceband Medium band Broadband Used for high capacity transmission Used by DSL, cable & satellite

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Protocols Set of communication rules Standard for Internet: TCP/IP Transmission control protocol/Internet protocol Identifies devices Reformats information

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Networks A computer network is a communication system Connects two or more computers Allows information exchange

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Network Terms Node Client Server Hub Network interface cards (NIC) Network operating system (NOS) Distributed processing Host computer Network manager

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Network Types Local area networks Home networks Metropolitan area networks Wide area networks

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Network Architecture Architecture describes how a network is arranged Arrangement is called topology Types of network topology Star Bus Ring Hierarchical

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Star Network Smaller computers linked to a central unit Central unit is called the network hub Control is maintained by polling

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Bus Network Each device handles its own communication control There is no host computer Has a common connecting cable called a backbone

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Ring Network Each device is connected to two other devices No central file server or computer Useful in a decentralized environment

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Hierarchical Network Several computers linked to a central host Computers are hosts to other computers Useful in centralized organizations

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Strategies Strategy is a way of coordinating the sharing of information and resources Common network strategies Terminal Client/server Peer-to-peer Peer-to-Peer Network System

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Organizational Internets

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved 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

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved A Look to the Future Wireless Robotic Car Pod car (Personalization on Demand) Predicts and responds Designed to learn and adapt to an individual's driving needs and habits

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Key Terms (239) analog signal (240) application server (243) asymmetric digital subscriber line (ADSL) (241) backbone (249) bandwidth (241) base station (245) bits per second (bps) (240) Bluetooth (239) broadcast radio (238) broadband (242) bus (249) bus network (249) cable modem (241) cellular phone system (245) client (243)

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Key Terms client/server network system (251) coaxial cable (238) communications (246) communication channel (237) communication device (237) communication server (243) communication system (237) computer network (243) connection device (237) connectivity (236) database server (243) data transmission specification (237) dedicated server (243)

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Key Terms demodulation (240) dial-up service (240) digital signal (240) digital subscriber line (DSL) (241) dish (239) Distributed data processing system (249) distributed processing (243) Domain name server (DNS) (242) downlink (239) external modem (240) extranet (243) fiber-optic cable (238) file server (243) firewall (253) Gnutella (252)

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Key Terms global positioning (239) global positioning system (GPS) (239) hierarchical network (249) home network (245) host computer (243) hub (243) hybrid network (249) infrared (238) internal modem (240) intranet (253) IP address (Internet Protocol address) (242) LAN adapter (243) line of sight communication (238) Local area network (LAN) (244)

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Key Terms low bandwidth (241) medium band (242) metropolitan area network (MAN) (245) microwave (239) microwave station (239) modem (240) modulation (240) Napster (251) network administrator (243) network architecture (248) network gateway (244) network hub (248) network interface card (NIC) (243) network manager (243)

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Key Terms network operating system (NOS) (243) node (243) packet (242) PC card modem (240) peer-to-peer network system (252) polling (248) printer server (243) protocol (242) proxy server (254) receiving device (237) regional network (245) ring network (249) satellite (239) Satellite/air connection service (241) sending device (237)

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Key Terms server (243) star network (248) strategy (250) TCP/IP (transmission control protocol/Internet protocol) (242) telephone line (238) terminal network system (250) time-sharing system (249) T1, T2, T3, T4 lines (240) topology (248) transceiver (238) transfer speed (240) transfer rate (240) transmission medium (237)

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Key Terms twisted pair (238) uplink (239) voiceband (241) voice grade (241) Web server (243) wide area network (WAN) (245) Wi-FI (wireless fidelity) (239) wireless LAN (WLAN) (245) wireless modem (240) wireless receiver (245)

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved FAQs What is fiber-optic cable? My Palm Pilot uses Bluetooth. What is it? What is a modem? What is DSL? How does it work? How fast is broadband bandwidth? What is a local area network? What is meant by peer-to-peer?

© 2005 The McGraw-Hill Companies, Inc. All Rights Reserved Discussion Questions Discuss what is meant by the wireless revolution. Discuss the four types of service connections. Discuss the advantages and disadvantages of the four network topologies. Explain the connections in a home network. Describe the different network topologies. Describe a GPS system.