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Telecommunications and Networks
Chapter 6 Telecommunications and Networks McGraw-Hill/Irwin Copyright © 2011 by The McGraw-Hill Companies, Inc. All rights reserved.
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Learning Objectives Understand the concept of a network Apply Metcalfe’s law in understanding the value of a network Identify major developments and trends in the industries, technologies, and business applications of telecommunications and Internet technologies
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Learning Objectives Provide examples of the business value of Internet, intranet, and extranet applications Identify the basic components, functions, and types of telecommunications networks used in business Explain the functions of major components of telecommunications network hardware, software, media, and services
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Learning Objectives Explain the concept of client/server networking Understand the two forms of peer-to-peer networking Explain the difference between digital and analog signals
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Interconnected chain, group, or system Connections created by nodes
Network Concepts Interconnected chain, group, or system Connections created by nodes Exponential growth Metcalf’s Law Usefulness, or utility, of a network Equals the square of the number of users More users = more useful A network is an interconnected or interrelated chain, group, or system Connections created by nodes follows the pattern of exponential growth. The number of possible connections on a network is N(N–1) or N2 –N N = number of nodes (points of connection) Example: 10 computers on a network = 10(10–1) = 10x9 = 90 possible connections Metcalfe’s Law The usefulness, or utility, of a network equals the square of the number of users The more users on a network, the more useful it becomes Early on, changes in technology only affect the technology, after a critical mass in the number of users is reached, a change in technology causes changes in social, political, and economic systems Result: With the exponential growth in the Internet, we can expect more value, for less cost, virtually every time we log on.
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RWC 1: Telepresence Is Finally Coming of Age
Immersive video experience Saves travel time and expense Video conferencing better for one-on-one Allows people to think globally
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Telecommunication Trends
Internet Networking Technologies Industry Trends Used as technology platform Web browser suites HTML Web page editors Firewalls Network management software Internet, intranet, and extranet applications Client/server networks Open-systems architecture Technology trends Use common standards Hardware, software, applications, and networks Internet networking technologies Connectivity Greater connectivity and network interoperability Middleware helps diverse systems work together Mediates between two separate programs Database access other databases without custom programming The “plumbing” of an information system Routes data and information between back-end data sources and end user applications Essential component of any IT infrastructure Digital Network Technologies Telecommunications revolutionized by switch from analog to digital Analog: voice-oriented transmission Digital: discrete pulse transmission Benefits Higher transmission speeds Moves larger amounts of information Greater economy and lower error rates Transmits multiple types of communications (data, voice, video) on the same circuits Wireless technologies Fiber-optic Pulses of laser-generated light Reduced size and installation effort Greater communication capacity Faster transmission speeds Freedom from electrical interference Satellite Transmission Massive quantities of data, audio, and video over global networks Useful in isolated areas Business Applications Telecommunications networks vital in … E-business processes Electronic commerce Enterprise collaboration Applications supporting operations, management, and strategic objectives Internet 2 Next generation of the Internet High-performance Different infrastructure Will not replace the current Internet Over 200 universities, scientific institutions, communications corporations May never become totally open Connected via Abilene , Backbone supporting throughput of 10 Gbps Infinite bandwidth
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Telecommunications-Based Services
Internet networking technologies are being used as technology platform Web browser suites HTML Web page editors Network management software Firewalls Being applied in Internet, intranet, and extranet applications Reinforces previous move toward client/server networks based on open-systems architecture
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Value of Telecommunications Networks
The Internet Revolution Global information superhighway Millions of smaller, private networks Independent In harmony with each other 10 servers in 1991 to over 46 million today Sustained growth in excess of 1 million servers per month No central computer system No governing body Common standards Internet Service Providers - ISP Provides easy access to the Internet Monthly fee Connected through network access points Uses of the Internet – Fig 6.5 – p. 227 Most popular uses Instant messaging Browsing the Web Newsgroups Chat rooms Publish opinions, subject matter, creative work Buy and sell Downloading data, software, reports, pictures, music, videos
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Business Use of the Internet
Business Value of the Internet Substantial Cost Savings Airline 90 percent less Banking 50-95 percent less
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Business Value of the Internet
Summary of bulleted list
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Intranets as Information Portals
Role of Intranets Sophisticated intranets offer… Detailed data retrieval Collaboration Personalized customer profiles Links to the Internet Intranets use Internet technologies Web browsers and servers TCP/IP network protocols HTML publishing and databases Business Value of Intranets Intranets support Communications and collaboration Business operations and management Web publishing Intranet portal management Allow productive use of intranet Protect the data resources Unauthorized access Viruses Directory management
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Extranet Connectivity
Extranets Network links that use Internet technologies to connect the intranet of a business to the intranets of another business Virtual Private Networks Private secure Internet links b/w companies Unsecured Extranet Internet link between companies encryption of sensitive data firewall security systems Business Value of Extranets Web browser technology makes customer and supplier access to intranets easier and faster Another way to build and strengthen strategic relationships Enables and improves collaboration between a business, customers, and partners Facilitates online, interactive product development and marketing
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RWC 2: Medicine through Videoconferencing
Visual-communication workstation connected to major hospital stroke center Improves Diagnostic ability Training of new doctors Communication with patients Handicapped Second-languages Discussion and collaboration
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Telecommunications Network Model
Telecommunications Alternatives Telecommunications is a highly technical, rapidly changing field Most business professionals don’t need detailed technical knowledge However, understanding basic components and their characteristics is necessary Can help you make informed decisions about telecommunications alternatives A telecommunications network is any arrangement where a sender transmits a message to a receiver over a channel consisting of some sort of medium
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Network Component Alternatives
Telecommunications Network Components Terminals Any input/output device that uses networks to transmit or receive data Telecommunications processors Devices that support data transmission, reception Telecommunications channels Media over which data are transmitted, received Computers All sizes and types Host, front-end processor, or server Telecommunications control software Controls telecommunications activities Manages the functions of telecommunications networks Network management programs Telecommunications monitors (mainframes) Network operating systems (network servers) Web browsers (microcomputers)
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Wide Area Network (WAN)
Types of Communications Networks Primary types of communications networks Wide Area Local Area Virtual Private Client/Server Peer-to-peer
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Local Area Network (LAN)
Connects computers in a limited physical area Office, classroom, or building Connects computers within a limited physical area, such as an office, classroom, or building
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Virtual Private Network
Virtual Private Networks (VPN) Used to establish secure intranets and extranets The Internet is the main backbone network Relies on network firewalls, encryption, and other security features to build a “pipe” through the Internet Creates a private network without the high cost of a separate proprietary connection
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Client/Server Network
Client/Server Networks Clients End user personal computers or networked computers Servers Used to manage the networks Processing Shared between the clients and servers Sometimes called a two-tier architecture Larger computer systems are being replaced with multiple client/server networks
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Networks are the central computing resource of the organization
Network Computing Network Computing Networks are the central computing resource of the organization Thin clients provide a browser-based user interface for processing applets Thin clients include Network computers Net PCs Other low-cost network devices or information appliances Application and database servers provide The operating system Application software Applets Databases Database management software Sometimes called a three-tier client/server model because it consists of Thin clients Application servers Database servers
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Peer-to-Peer Network Diagrams
Napster - Provided a central index for enabling peers on the fringe of the network to quickly locate available content BitTorrent - Provides a tool form managing bandwidth during periods of heavy traffic Blizzard Entertainment - Uses BitTorrent to manage bandwidth requirements for the World of Warcraft game PeerCast - One of several systems which allow broadcasting of Internet radio or television stations
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Telecommunications Media
Twisted-Pair Wire Similar to telephone wire Coaxial Cable Wire wrapped with insulation Fiber-Optic Cable One or more hair-thin filaments of glass Analog or digital - method used to convert information into an electrical signal Analog - power of an electrical current proportional (analogous) to the quantity The higher the value the more volts are sent 83 degrees - generate 8.3 volts Digital - quantity expressed as a number 83 degrees send on/off pulses in patterns to represent numbers in base 2 83 = = Twisted-Pair Wire Ordinary telephone wire Copper wire is twisted into pairs Unshielded 2 million bps Shielded 10 million bps Why difference? Coaxial Cable Sturdy copper or aluminum wire wrapped with spacers to insulate and protect it million bps 2 – 5 times faster than twisted pair Long distance Lakes, oceans Short distance Cities, buildings Fiber-Optic Cable One or more hair-thin filaments of glass fiber wrapped in a protective jacket 100 x faster than coaxial cable Requires few repeaters The Problem of the “Last Mile” Different technologies used Network providers use fiber optic cable as a communications backbone Houses connected to the backbone are wired with twisted pair Users don’t benefit from the faster, better technology Copper media Power weakens Need repeater
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Wireless Technologies
Communications Satellites Geosynchronous orbit Serve as relay stations Wireless LANS Wireless radio-wave technology Bluetooth Short-range wireless technology Other Wireless Systems Cellular phones, Mobile radio, PDAs Telecommunications vital and pervasive Web-enabled e-business processes Communications Satellites Geosynchronous orbit Serve as relay stations Use microwave radio signals Earth stations beam signals to the satellites Not suitable for interactive, real-time processing Time vs distance Wireless LANS Uses wireless radio-wave technology to connect PCs within an office or a building Can be high-frequency, similar to digital cellular, or low frequency (spread spectrum) Bluetooth Short-range wireless technology Connects PCs to devices, such as a printer Fairly low cost to implement Other Wireless Systems Cellular phones Mobile radio PDAs Telecommunications networks now play vital and pervasive roles in Web-enabled e-business processes Electronic commerce Enterprise collaboration Other applications that support business operations, management, and strategic objectives
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Wireless Technologies
Other Wireless Systems Cellular phones Mobile radio PDAs Telecommunications pervasive role Web-enabled e-business processes Electronic commerce Enterprise collaboration Other applications Business operations, management, strategic objectives Other Wireless Systems Cellular phones Mobile radio PDAs Telecommunications networks now play vital and pervasive roles in Web-enabled e-business processes Electronic commerce Enterprise collaboration Other applications that support business operations, management, and strategic objectives
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Web-enabled appliances proliferate
The Wireless Web Web-enabled appliances proliferate Smart telephones, pagers, PDAs All are very thin clients in wireless networks Wireless Internet access is growing as Web-enabled information appliances proliferate Smart telephones, pagers, PDAs All are very thin clients in wireless networks
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Telecommunications Processors
Modems Most common type Modulation and demodulation Converts for transmission over telephone lines Digital signal to analog Analog to digital Most common type of communications processor Converts a digital signal to an analog frequency that can be transmitted over phone lines, then back into a digital signal Modulation and demodulation
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Communications 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 with different communications architectures Multiplexer… allows a single communications channel to carry simultaneous data transmissions from many terminals In time division multiplexing (TDM), the multiplexer divides the time each terminal can use the high-speed into short time slots Multiplexers increase the number of transmissions possible Does not increase the number of physical data channels
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Comparing Technologies
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Telecommunications Software
May reside in PCs, servers, mainframes, and communications processors Vital part of all telecommunications networks Used to manage network performance WANs often use telecommunications monitors or teleprocessing monitors Other networks use operating system software Middleware helps diverse networks communicate with each other
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Network Management Functions
Traffic Management Security Network Monitoring Capacity Planning Traffic Management Manage network resources and traffic to avoid congestion and optimize service levels Security Provide authentication, encryption, firewall, auditing, and enforcement Network Monitoring Troubleshoot and watch over the network, alerting administrators of potential problems Capacity Planning Survey network resources, traffic patterns, and users’ needs Determine the best way to accommodate the needs of the network as it grows and changes
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Mesh Network – variation of ring network
Network Topologies Topology The structure of a network Star Network Ties end user computers to a central computer but not to each other Ring Network Ties local computer processors together in a ring on a relatively equal basis Bus Network Local processors share the same communications channel Mesh Network – variation of ring network Uses direct communications lines to connect some or all of the computers in the ring to each other Real World Case p st column, bottom Switch A message-switching computer that handles data communication between autonomous local computers
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Mesh Network – variation of ring network
Network Topologies Mesh Network – variation of ring network Uses direct communications lines to connect some or all of the computers in the ring to each other Real World Case p st column, bottom Switch A message-switching computer that handles data communication between autonomous local computers Mesh Network
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Network Architectures and Protocols
Rules and procedures Handshaking Exchanging predetermined to agree on a protocol Network Architecture Master plan of standards Goal is to promote an open, simple, flexible, and efficient telecommunications environment Protocol A standard set of rules and procedures for the control of communications in a network Handshaking The process of exchanging predetermined signals and characters so devices can agree on a communications protocol. Information transfer rate, coding alphabet, parity, interrupt procedure, and other protocol or hardware features. Network Architecture Master plan of standard protocols, hardware, software, and interfaces between end users and computer systems Goal is to promote an open, simple, flexible, and efficient telecommunications environment
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Open Systems Interconnection Model
OSI Model Open Systems Interconnection Model Seven-layer standard for network architectures Controls how messages should be transmitted Ensures consistency among products Open Systems Interconnection (OSI) Model A seven-layer standard model for network architectures Each layer adds functions Controls how messages should be transmitted between two points in a network Guides product developers so that their products will work consistently with other products.
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OSI and TCP/IP Models Internet Telephony
Voice Over IP Internet Telephony Using an Internet connection to pass voice data using IP instead of a telephone network Often referred to as voice over IP or VoIP Works like a regular phone, but skips long-distance charges Runs over standard network infrastructure Requires a well-configured network to work smoothly
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Transmission Speeds Bandwidth Transmission Rates
The frequency range of a telecommunications channel that determines the maximum transmission rate Speed and capacity typically measured in bits per second (bps) Sometimes call baud rate Transmission Rates Narrow-band = low speed Broadband = high speed
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RWC 3: Value of Secure Networks
Improves operational efficiency Secures sensitive data Contains costs Enhances employee connectivity Enhances customer responsiveness Allows customers to securely track orders in real time Empowers customer-service agents with detailed account information Provides easy, inexpensive videoconferencing 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.
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RWC 4: Future of Public WiFi
Wi-Fi fast-growing popularity Wi-Fi coffee shops replaced cybercafes Moves towards free Advertising offsets costs or to make money Increasingly always free everywhere Wi-Fi hot spots emerged several years ago because of the fast-growing popularity of laptops. Wi-Fi enabled coffee shops quickly supplanted the older style cybercafes, which relied on the expensive purchase and upkeep of PCs. Public Wi-Fi access is at crossroad with recent moves towards free and advertising-based provision of this service by Starbucks and others. As pressure mounts to make more Wi-Fi hot spots free, some companies are turning to Web advertising to offset costs or make money. Like television, Wi-Fi is increasingly given away in exchange for ads. Increasingly always free everywhere.
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