Chapter Communications and Networks McGraw-Hill Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved mputing Essentials 2012: Making IT Work for You Introduction • We live in a truly connected society • 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 McGraw-Hill Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-2 mputing Essentials 2012: Making IT Work for You Communications • Computer communications is the process of sharing data, programs, and information between two or more computers • Numerous applications depend on communication systems, including – – – – – E-mail Instant messaging Internet telephone Electronic commerce Global positioning systems (GPS) McGraw-Hill Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-3 mputing Essentials 2012: Making IT Work for You Communications Today • Connectivity uses computer networks to link people and resources • The Wireless Revolution – Single most dramatic change in connectivity and communications has been widespread use of mobile telephones with wireless Internet connectivity McGraw-Hill Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-4 mputing Essentials 2012: Making IT Work for You Communication Systems • Four basic elements – – – – McGraw-Hill Sending and receiving devices Communication channel Connection devices Data transmission specifications Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-5 mputing Essentials 2012: Making IT Work for You Communication Channels • Communication channels carry the data from one computer to another • Two categories of communication channels – Physical connection – Wireless connection McGraw-Hill Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-6 mputing Essentials 2012: Making IT Work for You Physical Connections • Ethernet cable (Twisted pair cable) • Coaxial cable • Fiber-optic cable McGraw-Hill Return Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-7 mputing Essentials 2012: Making IT Work for You Wireless Connections • Radio frequency (RF) – Wi-Fi (wireless fidelity) – Bluetooth (short-range) – WiMax (extends Wi-Fi) • Microwave • Satellite – Global positioning system (GPS) • Infrared – Short distances and line of sight McGraw-Hill Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-8 mputing Essentials 2012: Making IT Work for You McGraw-Hill Communication Channels Summary Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-9 mputing Essentials 2012: Making IT Work for You Connection Device Signals • Types of signals – Analog – Digital McGraw-Hill Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-10 mputing Essentials 2012: Making IT Work for You Networks • A computer network is a communication system that connects two or more computers • Allows exchange of information and resources McGraw-Hill Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-16 mputing Essentials 2012: Making IT Work for You Computer Networks • • • • • • • Node Client Server Directory server Host Switch Network interface cards (NIC) • Network operating systems (NOS) • Network administrator McGraw-Hill Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-17 mputing Essentials 2012: Making IT Work for You Network Types • Local area network (LAN) • Home network • Wireless LAN (WLAN) • Metropolitan area network (MAN) ã Wide area network (WAN) McGraw-Hill Copyright â 2012 The McGraw-Hill Companies, Inc All rights reserved 9-18 mputing Essentials 2012: Making IT Work for You Network Architecture • Arrangement is called topology • Types of network topology – Legacy • Bus • Ring – Current McGraw-Hill • Star • Tree ã Hybrid ã Mesh Copyright â 2012 The McGraw-Hill Companies, Inc All rights reserved 9-19 mputing Essentials 2012: Making IT Work for You Bus Network • Each device is connected to a common cable, called a bus or backbone • All communications travel along this bus • There is no host; messages are passed device-to-device in a sequence McGraw-Hill Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved Return 9-20