Communications and networks (NHẬP môn điện TOÁN SLIDE)

Chapter Communications and Networks McGraw-Hill Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved Computing 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 Computing 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 – – – – – McGraw-Hill E-mail Instant messaging Internet telephone Electronic commerce Global positioning systems (GPS) Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-3 Computing 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 Computing 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 Computing 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 Computing 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 Computing 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 Computing Essentials 2012: Making IT Work for You McGraw-Hill Communication Channels Summary Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-9 Computing 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 Computing 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 Computing 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 Computing 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 Computing 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 Computing 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 Return Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-20 Computing Essentials 2012: Making IT Work for You Ring Network • Each device is connected to two other devices • No central file server or computer • Useful in a decentralized environment McGraw-Hill Return Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-21 Computing Essentials 2012: Making IT Work for You Star Network • Most widely used network topology for both homes and large businesses • Each device connects directly to a central network switch McGraw-Hill Return Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-22 Computing Essentials 2012: Making IT Work for You Tree Network • Each device is connected to a central node, either directly or through subordinate nodes • Also known as a hierarchical network McGraw-Hill Return Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-23 Computing Essentials 2012: Making IT Work for You Hybrid Network • Combination of different topologies • Large organizations have a complex network of smaller networks – These smaller networks use a variety of configurations – When connected together, they form a hybrid McGraw-Hill Return Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-24 Computing Essentials 2012: Making IT Work for You Mesh Network • Does not use a specific physical layout, but requires that each node have more than one connection to other nodes • Wireless technologies are frequently used McGraw-Hill Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-25 Computing Essentials 2012: Making IT Work for You McGraw-Hill Network Topologies Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-26 Computing Essentials 2012: Making IT Work for You Network Strategies • • • • Terminal server network Client/server network Peer-to-peer (P2P) network Distributed processing network McGraw-Hill Terminal Client/Server Peer-to-Peer Server Copyright © 2012 The McGraw-Hill Companies, Inc All rights 9-27 reserved Computing Essentials 2012: Making IT Work for You Organizational Networks • Intranets – Private network within an organization – Works like the Internet, where employees use browsers to access Web sites and Web pages • Extranets – Private network that connects organizations – Works like the Internet, but provides suppliers and other trusted partners with limited access to the organization’s networks McGraw-Hill Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-28 Computing Essentials 2012: Making IT Work for You Network Security • Firewalls – Combination of hardware and software – Proxy server provides pass-through access – Protects against external threats • Intrusion detection systems (NIDS) • Virtual private networks (VPN) – Creates a secure private network connection between your computer and the organization McGraw-Hill Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-29 Chapter Chapter Communications and Networks STUDY p274 – 279 VISUAL SUMMARY MULTIPLE CHOICE Q’s McGraw-Hill KEY TERMS MATCHING Q’s Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved ... Making IT Work for You Bandwidth • Measurement of the width or capacity of the communication channel • Categories – Voice band (or low bandwidth) – Medium band – Broadband – Baseband McGraw-Hill Copyright... 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. .. connection between your computer and the organization McGraw-Hill Copyright © 2012 The McGraw-Hill Companies, Inc All rights reserved 9-29 Chapter Chapter Communications and Networks STUDY p274 – 279