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Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-1 MANAGING INFORMATION TECHNOLOGY 7 th EDITION CHAPTER 3 TELECOMMUNICATIONS AND.

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Presentation on theme: "Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-1 MANAGING INFORMATION TECHNOLOGY 7 th EDITION CHAPTER 3 TELECOMMUNICATIONS AND."— Presentation transcript:

1 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-1 MANAGING INFORMATION TECHNOLOGY 7 th EDITION CHAPTER 3 TELECOMMUNICATIONS AND NETWORKING

2 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-2 PART 1: IT BUILDING BLOCKS Building Blocks of Information Technology HardwareSoftware Network Data

3 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-3 NETWORKING AND TELECOMMUNICATIONS. NETWORKING: The electronic linking of geographically dispersed devices TELECOMMUNICATIONS: Communications at a distance, including voice and data - Also referred to as: data communications, datacom, teleprocessing, telecom, and networking

4 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-4 OVERVIEW OF TELECOMMUNICATIONS AND NETWORKING Telecommunications and networking have become increasingly important to businesses because of distributed processing and globalization Early 1990s prediction came true: “ …networks will change everything" - Paul Saffo

5 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-5 THE TELECOMMUNICATIONS INDUSTRY Three Major Segments of Telecom Industry: Carriers who own or lease physical plant & sell the service of communications transmission Equipment vendors who manufacture and sell telecommunications equipment Service providers who operate and deliver network services or provide access to or deliver services via the Internet

6 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-6 THE TELECOMMUNICATIONS INDUSTRY Example: AT&T One of largest carriers in U.S. industry In 1984, AT&T split into several companies as a result of a US Department of Justice antitrust lawsuit Breakup of AT&T led to greater innovation through competition But recent trend has been consolidation in the industry

7 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-7 REASONS FOR NETWORKING Five primary reasons for networking 1.Sharing of technology resources 2.Sharing of data 3.Distributed data processing and client/server systems 4.Enhanced communications 5.Marketing outreach

8 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-8 REASONS FOR NETWORKING 1. Sharing of technology resources: Prior to networking capabilities, computers could not even share printers…. Today, PCs share software, mainframes share storage devices, etc. 2. Sharing of data: Enables retrieval of data stored on other nodes in the network Allows efficient transactions between businesses, their suppliers, and their customers, based on up-to-date data Some businesses share many terabytes of data per day Sharing of data via Internet users

9 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-9 REASONS FOR NETWORKING 3.Distributed data processing and client/server systems: Distributed data processing Information processing that uses multiple computers at multiple sites that are tied together through telecommunication lines Client/server systems A type of distributed system in which the processing power is distributed between a central server and a number of client computers ClientServer Transfer of Data

10 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-10 REASONS FOR NETWORKING 4. Enhanced communications: Telecommunication networks provide the ability to communicate through , Bulletin Boards, Blogs, Instant Messaging, Wikis, Social network sites, Videoconferencing Links between organizations can lead to strategic alliances o SABRE airline reservation system o Electronic data interchange (EDI) 5. Marketing outreach: Sharing data via the Internet with consumers = an important marketing and sales channel

11 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-11 FUNCTIONS OF A TELECOMMUNICATIONS NETWORK A telecommunications network is more than a series of wires or wireless signals… Table 3.1

12 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-12 ANALOG AND DIGITAL SIGNALS Analog Signals A signal in which some physical property continuously varies across time Digital Signals A signal that is not a continuous function of time, but rather a series of discrete values that represent ones and zeros

13 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-13 ANALOG AND DIGITAL SIGNALS Representation of digital and analog signals

14 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-14 ANALOG AND DIGITAL SIGNALS Digital computer data does not naturally mesh with analog transmission; it must be converted from ones and zeros to analog signals Solutions: Modem (Modulator/Demodulator) Digital networks Advantages of lower error rates and higher speeds

15 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-15 TYPES OF TRANSMISSION LINES  Private (dedicated physical lines) Advantage: - Ensures quality of transmission Disadvantage: -Costly  Switched (such as public telephone network) Advantage: - Less costly Disadvantages: - Message may take many different routes - Quality of transmission may degrade

16 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-16 TYPES OF TRANSMISSION LINES Simplex Data can only travel in one direction Half Duplex Data can travel in both directions, but not simultaneously Full Duplex Data can travel in both directions at once

17 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-17 TRANSMISSION MEDIA  Twisted Pair Literally, wires that are twisted to reduce interference Can be shielded (STP) or unshielded (UTP), but the most commonly used is UTP Medium used for public telephone networks Transmission speeds vary greatly

18 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-18 TRANSMISSION MEDIA  Coaxial (Coax) Cable Baseband - Inexpensive, designed for digital transmission Broadband - Originally for analog, now used for digital - Commonly used in television cable Figure 3.2

19 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-19 TRANSMISSION MEDIA  Wireless Not truly a transmission medium, but rather a broadcast technology in which radio signals are sent through the air Cordless telephones and cellular telephones now widely used Wireless technologies: Wireless LANs Microwave – Line of sight Satellite – Long distances – Line of sight RFID Bluetooth Wireless Cards

20 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-20 TRANSMISSION MEDIA  Wireless Wireless LANs - Growing in popularity - Useful when wiring is not possible - Slower than some wired solutions - Allow mobile devices to connect to network

21 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-21 TRANSMISSION MEDIA  Wireless Microwave - Widespread use for several decades - Line of sight transmission - Limited to mile distances because of curvature of the earth - Expensive, but less costly than fiber optic cables Microwave Tower

22 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-22 TRANSMISSION MEDIA  Wireless Satellite 1.Geostationary Earth Orbit (GEO) - Remains stationary relative to earth 2.Low Earth Orbit ( LEO) to 1000 miles above earth Figure 3.3

23 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-23 TRANSMISSION MEDIA LEO projects beginning in 1990s Iridium - First major LEO project with 66 satellites - Faced high operating costs which resulted in bankruptcy -Mostly military subscribers Globalstar - LEO project with 40 satellites that does not provide global coverage Teledesic - Ambitious project with original plans to launch 840 satellites - This was later cut to 288 satellites, then 30, and then the program was cancelled

24 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-24 TRANSMISSION MEDIA  Wireless RFID - Acronym for Radio Frequency Identification - An old technology that became popular in business after Wal-Mart required the use of RFID by some of its suppliers to improve inventory and supply chain management Wal-Mart and RFID Wal-Mart CIO on RFID Wal-Mart gets tough with suppliers about RFID

25 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-25 TRANSMISSION MEDIA  Wireless RFID Two Broad Types of RFID tags: - Active – these tags have their own power supply and can transmit messages continuously, on request, or on a schedule Cost over $ Passive – these tags only send a response to an incoming radio signal Cost in the $ $0.20 range

26 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-26 TRANSMISSION MEDIA  Wireless Bluetooth Named after Danish King who united Denmark Short-range radio technology Designed to consume very little electrical power and be produced at a low cost Found in a growing number of devices such as cell phones, laptops, headsets, keyboards, mice, and home appliances - Thousands of Bluetooth products in use today Bluetooth Devices

27 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-27 TRANSMISSION MEDIA  Fiber Optics Light pulses through a thin fiber of glass or silica Faster and more reliable than other media Large diameter fiber is multimode (multiple light rays at the same time) while smaller diameter is single mode But smaller diameter fiber has larger capacity due to light rays bouncing less….

28 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-28 NETWORK ACCESS FOR INDIVIDUALS Internet Service Providers (ISPs) sell access to the Internet Consumers now have more options including faster broadband connections - Digital Subscriber Line (DSL) is a connection through a telephone company - Cable modem is a connection through a cable television company - Satellite With one-way service, individuals must obtain uplink service from another provider -Other Wireless access may be through a municipal carrier or a private company Pricing methods for personal Internet access - Fixed price (usually monthly plans) -But hotels, airports, cafes, etc. now offer Internet access for short periods of time - Cost based on usage (data transferred) - Also offered “free” to customers in various locations

29 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-29 NETWORK TOPOLOGY Network topology = configuration or arrangement of the devices Figure 3.4 Bus - All devices are attached to one cable - Single-point failure Ring - Similar to bus, but ends are attached - Not susceptible to single-point failure Star - All nodes are attached to central device - Susceptible to failure of central device, but easy to identify cable failure Tree - Similar to the star, but with a hierarchical structure Mesh - Devices link to multiple other devices - A failure has little impact on the network, but costly

30 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-30 NETWORK TYPES Six types : 1.Computer Telecommunications Networks 2.Local Area Networks (LANs) 3.Backbone Networks 4.Wide Area Networks (WANs) 5.The Internet 6.Internet2

31 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-31 NETWORK TYPES 1.Computer Telecommunications Networks: This was the only type of network until the 1980s Commonly used in mainframe architectures Figure 3.5

32 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-32 NETWORK TYPES 2.Local Area Networks (LANs) -Standards developed by the Institute for Electrical and Electronic Engineering (IEEE) IEEE 802 is a family of standards for LANs and metropolitan area networks - Five types of LANs in common use today – 3 wired, 2 wireless o Contention Bus (IEEE 802.3) o Token Bus (IEEE 802.4) o Token Ring (IEEE 802.5) o Wi-Fi (IEEE ) o WiMAX (IEEE e)

33 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-33 NETWORK TYPES - LAN o Contention Bus (IEEE 802.3) - Developed by Xerox - Usually called Ethernet after the original Xerox version - Half-duplex - All devices must contend to use CSMA/CD protocol for collisions

34 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-34 NETWORK TYPES - LAN o Token Bus (IEEE 802.4) - A token (special message) is passed among devices - Only the device with the token can transmit a message -Important for Manufacturing Automation Protocol (MAP) o Token Ring (IEEE 802.5) - Developed by IBM -Combination of ring topology with use of tokens (used the same way as in token bus )

35 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-35 NETWORK TYPES - LAN o Wi-Fi (IEEE ) - Short for Wireless Fidelity -Most common wireless LAN type today - Uses a shared Ethernet design - CSMA/CA Protocol Similar to CSMA/CD, but with less collisions - Commonly used in offices to supplement wired Ethernet networks and support mobile devices, or in areas where adding hardwiring is problematic - Many U.S. cities are offering Wi-Fi networks

36 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-36 NETWORK TYPES o WiMAX (802.16e) - Newest of the network types -Similar to Wi-Fi, but operates over longer distances and at higher speeds - Can use both licensed and non-licensed frequencies -Clearwire = leading vendor at this time

37 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-37 NETWORK TYPES Wireless Local Area Networks: Some Implementation Problems - More difficult to secure than other network types - Organizations that offer wireless access to entice customers have problems with non-customers or unprofitable customers overusing the network - Unauthorized wireless use is also problematic in condos and apartments Multiple Unsecured Wireless Networks

38 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-38 NETWORK TYPES 3. Backbone Networks Connect LANs Key to internetworking Figure 3.8

39 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-39 BACKBONE NETWORK DEVICES Hardware devices for backbone (middle-distance) networks Hub: Simple device that forwards all messages to every device attached to it Wireless Access Point: Central device that connects wireless LAN to other networks Bridge: Connects two LAN segments and only forwards messages that need to go to other segment Switch: A multiport bridge; connects two or more LAN segments Router: Connects two ore more LANs and only forwards messages that go to the other LAN

40 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-40 NETWORK TYPES 4. Wide Area Networks (WANs) Similar to LANs, but cover greater distances (“long-haul”) We will consider the following three general types of WANs because they each have advantages and disadvantages: - Switched Circuit -Dedicated Lines -Packet-switched

41 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-41 NETWORK TYPES - WAN Switched Circuit (or circuit-switched): A single physical path is temporarily created between two nodes for their exclusive communication Most widely available means of implementing a WAN using a switched circuit connection is to use the ordinary telephone network Advantages - Easy to set up Disadvantages - Low speed - High error rates There are two different pricing schemes available for this service - Direct Distance Dialing (DDD) - pay for usage - Wide Area Telephone Service (WATS) - fixed rate

42 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-42 NETWORK TYPES - WAN Dedicated Lines: These are permanent channels exclusive to the business Advantages - High capacity - Low error rates Disadvantages -Expensive Two different types of dedicated circuits: - Leased lines are cable, microwave, or fiber connections - Satellite circuits are popular for organizations with many global locations - SONET lines are high-capacity leased fiber lines Table 3.3 Wide Area Networks

43 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-43 Packet-switched: Multiple connections exist simultaneously over the same physical circuit Messages are broken up into packets Businesses use PADs (Packet assembly/disassembly devices) to connect their networks to a common carrier network Figure 3.9 Advantages - Efficient use of network - Can be high capacity Disadvantages - Packets may arrive in different order or with delay NETWORK TYPES - WAN

44 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-44 NETWORK TYPES 5. The Internet -Network of networks that use the TCP/IP protocol -Similar to an enormous WAN -733 million hosts as of January Began with ARPANET and NSFNET ARPANET (Advanced Research Projects Agency Network) was created by the US Department of Defense NSFNET (National Science Foundation Network) was created to link supercomputers for research Each of these were largescale, packet-switching networks that led to the creation of the Internet ARPANET NSFNET

45 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-45 NETWORK TYPES Internet Applications

46 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-46 NETWORK TYPES 6. Internet2 -Not-for-profit consortium made up of over 200 universities, as well as industry and government partners, to develop and deploy advanced network applications and technologies for research and commercial purposes -Goals Create a leading-edge network capability for the national research community Enable revolutionary Internet applications based on a much higher-performance Internet than we have today Ensure the rapid transfer of new network services and applications to the broader Internet community

47 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-47 NETWORKING PROTOCOLS Network Protocols – An agreed-upon set of rules or conventions governing communication among elements of a network – Open Systems Interconnection (OSI) Reference Model Skeleton for standards developed by International Organization for Standardization (ISO) Conceptual framework to understand how communications in networks take place Figure 3.11

48 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-48 NETWORKING PROTOCOLS Transmission Control Protocol/Internet Protocol (TCP/IP) Created to link different types of networks (e.g., satellite and ground packet networks) together into a network of networks Has become de facto standard protocol for networking -TCP is responsible for the reliable and ordered transmission of messages - IP is responsible for routing individual packets based on their individual addresses (IP addresses) Roughly corresponds to network and transport layers of OSI model

49 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-49 NETWORKNG HAS BECOME CRITICAL TO DO BUSINESS Networking and Telecommunications have become necessary for businesses to function Increasing access to the Internet in developing countries due to new lines being funded by private and public organizations Impact of cut Internet cables in Middle EastImpact of cut Internet cables in Middle East

50 Copyright © 2011 Pearson Education, Inc. publishing as Prentice Hall 3-50 COPYRIGHT All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Printed in the United States of America. Copyright © 2012 Pearson Education, Inc. Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall


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