Chapter 6 Telecommunications and Networks Mc Graw-Hill Irwin

Chapter 6 Telecommunications and Networks Mc. Graw-Hill/Irwin © 2008, The Mc. Graw-Hill Companies, All Rights Reserved

Learning Objectives 1. Understand the concept of a network. 2. Apply Metcalfe’s law in understanding the value of a network. 3. Identify several major developments and trends in the industries, technologies, and business applications of telecommunications and Internet technologies. 4. Provide examples of the business value of Internet, intranet, and extranet applications. 6 - 2

Learning Objectives 5. Identify the basic components, functions, and types of telecommunications networks used in business. 6. Explain the functions of major components of telecommunications network hardware, software, media, and services. 7. Explain the concept of client/server networking. 8. Understand the two forms of peer-to-peer networking. 9. Explain the difference between digital and 6 - 3 analog signals.

Learning Objectives 10. Identify the various transmission media and topologies used in telecommunications networks. 11. Understand the fundamentals of wireless network technologies. 12. Explain the concepts behind TCP/IP. 13. Understand the seven layers of the OSI network model. 6 - 4

Network Concepts • Network – An interconnected chain, group or system • Number of possible connections on a network is N * (N-1) – Where N = number of nodes (points of connections on the network) – Example, if there are 10 computers on a network, there are 10 * 9 = 90 possible connections 6 - 5

Metcalfe’s Law • The usefulness of a network equals the square of the number of users • On a small network, a change in technology affects technology only • On a large network like the Internet, a change in technology affects social, political and economic systems 6 - 6

Telecommunications • Telecommunications – Exchange of information in any form (voice, data, text, images, audio, video) over networks 6 - 7

Trends in Telecommunications 6 - 8

Open Systems • Information systems that use common standards for hardware, software, applications and networks • Internet networking technologies are a common standard for open systems • Connectivity: – Ability of networked computers to easily access and communicate with each other and share information • Interoperability: – The ability of an open system to enable end user applications to be accomplished using different varieties of computer systems, software packages, and databases provided by a variety of interconnected networks 6 - 9

Middleware • Any programming that serves to “glue together” two separate programs 6 - 10

Digital Network Technologies • Rapid change from analog to digital network technologies • Analog: voice-oriented transmission, sound waves • Digital: discrete pulse transmission • Digital allows: – Higher transmission speed – Larger amounts of information – Greater economy – Lower error rates – Multiple forms of communications on same circuit 6 - 11

Internet 2 • Next generation of the Internet • High-performance network • In use at 200 universities, scientific institutions, communications corporations 6 - 12

Business Value of Telecommunication Networks 6 - 13

The Internet • Over 46 million servers (2004) • 710 – 945 million users (2004) • No central computer system • No governing body • No one owns it 6 - 14

Internet Service Provider • ISP – A company that specializes in providing easy access to the Internet – For a monthly fee, you get software, user name, password and access • ISPs are connect to one another through network access points 6 - 15

Popular uses of the Internet 6 - 16

Using the Internet for business 6 - 17

Business value of the Internet 6 - 18

An Intranet • A network inside an organization – That uses Internet technologies (such as Web browsers and servers, TCP/IP protocols, HTML, etc. ) – To provide an Internet-like environment within the organization – For information sharing, communications, collaboration and support of business processes – Protected by security measures – Can be accessed by authorized users through the Internet 6 - 19

Enterprise Information Portal 6 - 20

Extranet • Network links that use Internet technologies – To connect the Intranet of a business – With the Intranets of its customers, suppliers or other business partners 6 - 21

Extranet Uses 6 - 22

Telecommunications network • Any arrangement where a sender transmits a message to a receiver over a channel consisting of some type of medium 6 - 23

Telecommunications network components • Terminals: any input/output device that uses networks to transmit or receive data • Telecommunications Processors: devices that support data transmission and reception • Telecommunications Channels: media over which data are transmitted and received • Computers: all sizes and types • Telecommunications Control Software: programs that control telecommunications activities 6 - 24

Telecommunications network model 6 - 25

Wide Area Network (WAN) • Telecommunications network that covers a large geographic area Source: Courtesy of Cisco Systems Inc. 6 - 26

Local Area Network (LAN) • Connect computers within a limited physical area such as an office, classroom, or building 6 - 27

Virtual Private Networks (VPN) • A secure network that uses the Internet as its backbone but relies on firewalls, encryption and other security • A pipe traveling through the Internet 6 - 28

VPN 6 - 29

Client/Server networks • Clients: End user personal computers or networked computers • Interconnected by LANs • Servers: manage networks • Processing shared between clients and servers 6 - 30

Client/Server Network 6 - 31

Network Computing • Networks are the central computing resource of the organization • Thin clients: network computers and other clients provide a browser-based user interface 6 - 32

Peer-to-peer networks • Networks that connect from one PC to another PC • Common use is the downloading and trading of files 6 - 33

Peer-to-Peer Network 6 - 34

Telecommunications Media • Twisted-pair wire: – Ordinary telephone wire – Copper wire twisted into pairs Source: Phil Degginger/Getty 6 - 35 Images.

Telecommunications Media • Coaxial cable: – Sturdy copper or aluminum wire wrapped with spacers to insulate and protect it Source: Ryan Mc. Vay/Getty 6 - 36 Images.

Telecommunications Media • Fiber-optic cable: – One or more hair-thin filaments of glass fiber wrapped in a protective jacket Source: CMCD/Getty Images. 6 - 37

Problem of “The Last Mile” • Network providers use fiber optic to provide backbone • But houses are connected to the backbone via twisted-pair • Cannot get the benefit of the faster, better technology 6 - 38

Wireless Technologies • Terrestrial microwave – Earthbound microwave systems that transmit highspeed radio signals in a line-of-sight path – Between relay systems spaced approximately 30 -miles apart • Communications satellites – Satellite serves as relay stations for communications signals – Uses microwave radio signals 6 - 39

Wireless Technologies • Cellular and PCS telephone and pager systems – Divide the geographic area into small areas or cells – Each cell has transmitter or radio relay antenna to send message from one cell to another • Wireless LANs – Radio signals within an office or building – Connect PCs to networks • Bluetooth – Short-range wireless technology – To connect PC to peripherals such as printer 6 - 40

Wireless Web • Connect portable communications devices to the Internet 6 - 41

Telecommunications Processors • Modems – Convert digital signals from a computer into – Analog frequencies that can be transmitted over ordinary telephone lines 6 - 42

Comparing modem and other technologies 6 - 43

Internetwork Processors • Switch – makes connections between telecommunications circuits in a network • Router – intelligent communications processor that interconnects networks based on different protocols • Hub – a port switching communications processor • Gateway – connects networks using different communications architectures 6 - 44

Communications Processors 6 - 45

Telecommunications Processors • Multiplexer – Allows a single communications channel to carry simultaneous data transmissions from many terminals 6 - 46

Telecommunications Software • Used by servers and other computers to manage network performance • Network Operating Systems • Middleware 6 - 47

Network management functions • Traffic Management – manage network resources and traffic to avoid congestion and optimize service levels to users • Security – provide authentication, encryption, firewall, auditing and enforcement • Network Monitoring – troubleshoot and watch over the network, informing network administrators of potential problems before they occur • Capacity Planning – survey network resources and traffic patterns and users’ needs to determine how best to accommodate the needs of the network as it grows and changes 6 - 48

Network Topologies • Topology: structure of a network • Star: ties end user computers to a central computer • Ring: ties local computer processors together in a ring on a relatively equal basis • Bus: local processors share the same communications channel 6 - 49

Network Topologies 6 - 50

Network Architectures & Protocols • Protocol: standard set of rules and procedures for the control of communications in a network • Network Architecture: – Master plan of standard protocols, hardware, software and interfaces between end users and computer systems – Goal of promoting an open, simple, flexible, and efficient telecommunications environment 6 - 51

OSI & TCP/IP Models • Open Systems Interconnection (OSI) Model – A seven-layer model that serves as a standard model for network architectures – Model for how messages should be transmitted between two points in a network – Each layer adds functions • Transmission Control Protocol / Internet Protocol (TCP/IP) – A five layer telecommunications protocol used by the Internet 6 - 52

OSI & TCP/IP Models 6 - 53

Internet Telephony • Using an Internet connection to pass voice data using IP • Voice over IP (Vo. IP) • Skips standard long-distance phone charges 6 - 54

Bandwidth • Bandwidth – Frequency range of a telecommunications channel – Determines transmission rate – Classified in bits per second (bps) • Transmission Rates: – Narrow-band – low-speed – Broadband – high-speed 6 - 55

Transmission Speeds 6 - 56

Switching Alternatives • Circuit Switching – Switch opens a circuit to establish a link between a sender and receiver – it remains open until the communication session is completed • Packet Switching – Break messages into groups called packets – Transmit packets separately 6 - 57

Network Interoperability • Ensure that anyone anywhere on one network • Can communicate • With anyone anywhere on another network • Telecommunications as discussed in this chapter wouldn’t be possible without interoperability 6 - 58

Case 1: Best Buy, Med. Star Health, and Unifi: The Challenges and Benefits of Wireless Mobile Applications • Geek Squad is a 24 -hour response unit that offers computer and network support for home PC users or businesses without an onsite IT staff. • They use wireless Pocket PCs and other mobile devices to access company’s business applications. • The biggest challenge - typing on their small pocket PCs. • Many businesses that provide or manage employees’ mobile devices for accessing company information are developing their own software for mobile devices. 6 - 59

Case Study Questions 1. What are the business advantages and limitations of the Best Buy Geek Squad’s use of their wireless Pocket PC mobile devices? How have they overcome the limitations of their mobile devices? 2. What are the software development challenges of wireless mobile devices? How are Med. Star Health and Unifi meeting those challenges? 3. Why don’t the companies in this case use some of the thousands of software packages available for their wireless mobile devices? What are the advantages and limitations of this approach? 6 - 60

Real World Internet Activity 1. Use the Internet to research wireless mobile devices like the Sprint PPC-6700. Do an analysis of the desirable features and limitations of the smart wireless mobile device you would most be willing to use in a work situation. Defend your choice. 6 - 61

Real World Group Activity 2. While Best Buy has standardized on the Sprint PPC-6700 for its Geek Squad, Med. Star Health lets their medical practitioners pick their own devices. Should companies mandate a standard wireless mobile device for their employees? – Discuss the pros and cons of this question; then formulate and defend a proposed solution. 6 - 62

Case 2: Metric & Multistandard Components Corporation • A secure network foundation can improve a small company’s operational efficiency, secure sensitive data, contain costs, and enhance employee connectivity and customer responsiveness. – It allows customers to securely track their orders in real time over the Web – It empowers customer-service agents with detailed account information to answer their customer’s enquiry – It can provide easy, inexpensive videoconferencing for remote workers, vendors, and customers. 6 - 63

Case Study Questions 1. What were the most important factors contributing to MMCC’s success with its new, secure, self-managed network? Explain the reasons for your choices. 2. What are some of the business benefits and challenges of self-managed and externally managed networks? 3. Which type of network management would you advise small-to-medium business firms to use? Explain the reasons for your recommendation. 6 - 64

Real World Internet Activity 1. Use the Internet to discover more about the telecommunications products and services and current business performance and prospects of Cisco Systems and Hi-Link and some of their many competitors in the telecom industry. – Which telecom hardware and software company and IT consulting firm would you recommend to a small-to -medium business with which you are familiar? Explain your reasons to the class. 6 - 65

Real World Group Activity 2. In telecommunications network installation and management, as in many other business situations, the choice between “do it yourself” and “let the experts handle it” is a crucial business decision for many companies. – Debate this choice for small-to-medium businesses. See if you can agree on several key criteria that should be considered in making this decision, and report your conclusions to the class. 6 - 66

Case 3: SAIC, Hewlett-Packard, GE, and Others: The Business Case for Wireless Sensor Networks • Wireless sensor devices, or “motes, ” can detect changes in temperature, pressure, moisture, light, sound, or magnetism and report the information using wireless radio. • They are a giant leap compared to traditional sensors. • Motes cost about $100 each and are much cheaper to install. • The worldwide market for wireless sensors is expected to grow from $100 million in 2005 to more than $1 billion by 2009. 6 - 67

Case Study Questions 1. What are some of the business benefits associated with using wireless networks to collect and transmit data? 2. What are some of the challenges faced by this use of wireless technologies? What solutions can you offer? 3. The use of wireless networking as described in the case is both innovative and functional. What other business uses can you envision for this approach? 6 - 68

Real World Internet Activity 1. The companies mentioned in the case—Intel, IBM, SAIC, and GE—are all familiar names often associated with innovative approaches to technology. – Using the Internet, see if you can find examples of other companies that have found ways in which to apply mote wireless technology to business needs. 6 - 69

Real World Group Activity 2. One way of describing this use of wireless technologies is that it represents a marriage between RFID (we learned about these devices in Chapter 3) and wireless networking. This combination of enabling technologies results in an entirely new way of accomplishing an old task. – Brainstorm other combinations of existing technologies to create new approaches to existing business activities. 6 - 70