Telecommunications and Networks Chapter 6 Copyright © 2010 by the McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin
Dec 13, 2015
Telecommunicationsand Networks
Chapter 6
Copyright © 2010 by the McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill/Irwin
6-2
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
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
Explain the concept of client/server networking
Understand the two forms of peer-to-peer networking
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Network Concepts
A network is:
– an interconnected or interrelated chain, group, or system
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Telecommunication Trends
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Telecommunications-Based Services
1- Industry trends:
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2- Technology Trends
Internet networking technologies are being used as a 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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Digital Network Technologies
Telecommunications are being revolutionized by the switch from analog to digital– Analog: voice-oriented transmission– Digital: discrete pulse transmission
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Digital Network Technologies
Benefits– Higher transmission speeds– Moves larger amounts of information– Greater economy and much lower error rates– Transmits multiple types of communications
(data, voice, video) on the same circuits
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Wireless Technologies
Fiber-optic– Uses pulses of laser-generated light– Reduced size and installation effort– Vastly greater communication capacity– Faster transmission speeds– Freedom from electrical interference
Satellite Transmission– Can move massive quantities of data, audio,
and video over global networks– Especially useful in isolated areas
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3- Business Application Trends
Electronic commerce
Enterprise collaboration
E-business processes
Other applications that support operations, management, and strategic objectives
Telecommunications networks now play a vital and pervasive role in Web-enabled…
6-11
Internet2 – The Next Generation
High performanceHigh performance
Users connect via Abilene at 120 Gbps
Users connect via Abilene at 120 Gbps
Will not replace current Internet
Will not replace current Internet
Different infrastructureDifferent infrastructure
In limited use already
In limited use already
May never become totally open
May never become totally open
Infinitebandwidth
Infinitebandwidth
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The Business Value of Telecommunications Networks
Overcome time barriers
Overcome time barriers
Overcome cost barriers
Overcome cost barriers
Overcome structural barriers
Overcome structural barriers
Overcome geographic
barriers
Overcome geographic
barriers
StrategicCapabilitiesStrategic
Capabilities
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The Internet Revolution
The Internet is a global information superhighway
Millions of smaller, private networks
10 servers in 1991 to over 46 million today
Growing by 1 million servers per month
No central computer system
No governing body
Based on common standards
6-14
Internet Service Providers
For a monthly fee, they provide software, user names, passwords, and Internet access
Companies that specialize in providingeasy access to the Internet
One ISP can easily connect to another to obtain addresses of websites or user nodes
ISPs themselves are connected to one another through network access points
6-15
Popular Uses of the Internet
SurfSurf
ConnectConnect
DownloadDownload
DiscussDiscuss
Phone CallsPhone Calls
E-MailE-Mail
PublishPublish
And more…And more…
ComputeCompute
Buy & SellBuy & Sell
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Business UseUse of the Internet
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Business ValueValue of the Internet
E.g. Airline company
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The RoleRole of IntranetsIntranets
Many companies have sophisticated
and widespread intranets
Intranets use Internet
technologies
Detailed data retrieval
Collaboration
HTML publishing and databases
Personalized customer profiles
Web browsers and servers
Links to the Internet
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Intranets
Encryption
Passwords FirewallsIntranets are
protected by…
Customers, suppliers, and other business partners can access an intranet via extranet links
6-20
Intranets as “Enterprise Information Portals”
E.g. College
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Extranets
Uses Internet technologies to connect the intranet of a business
to the intranets of another
Direct private network links, or private secure Internet links
between companies
Link between a company and others via the Internet, relying on encryption of sensitive data and
firewall security systems
NetworkLinks
Virtual Private Networks
UnsecuredExtranet
6-22
Extranet Connectivity and Value
6-23
Telecommunications Network Alternatives
Telecommunications is a highly technical, rapidly changing field
Most business professionals don’t needdetailed technical knowledge
However, understanding basic componentsand their characteristics is necessary
Can help you make informed decisions abouttelecommunications alternatives
6-24
Telecommunications Network Model
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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Telecommunications Network Components
1. Terminals: Any input/output device that uses networks to transmit or receive data
2. Telecommunications processors: Devices that support data transmission, reception
3. Telecommunications channels: Media over which data are transmitted, received
4. Computers: All sizes and types
5. Telecommunications control software:1. Controls telecommunications activities2. Manages the functions of telecommunications networks
3. Includes network management programs of all kinds1. Telecommunications monitors (mainframes)2. Network operating systems (network servers)3. Web browsers (microcomputers)
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Types of Communications Networks
CommunicationNetworks
Wide Area
Peer-to-Peer
Client/Server
Virtual Private
Local Area
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Wide Area Network (WAN)
Covers a large geographic area
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Metropolitan Area Networks (MANs)
Metropolitan Area Networks: a wide area network that optimizes a specific geographical area.
E.g. MAN covering a city or a couple of cities
E.g. Royal Commission TV cable
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Local Area Network (LAN)
Connects computers within a limited physical area,such as an office, classroom, or building
6-30
Virtual Private Network
6-31
Virtual Private Network
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
6-33
Client/Server Network
Clients
– End user personal computers or networked computers
Servers
– Used to manage the networksProcessing
– Shared between the clients and servers
– Sometimes called a two-tier architectureLarger computer systems are being replaced
with multiple client/server networks
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Peer-to-Peer Networks
Central Server Architecture
P2P file-sharing software connects all PCsto a central server
Clicking a link connects the two PCs andautomatically transfers the file to the
requesting PC
The server sends the requesting PC a list oflinks to all active peers who have the file
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Peer-to-Peer Networks
Pure Peer-to-Peer Architecture
No central directory or server
File-sharing software connectsone PC to another online user
When you request a file, the softwaresearches every online user, then sends
you a list of active file names
Clicking a link automatically transfers the filefrom that user’s hard drive to yours
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Central Server Peer-to-Peer Networks
Advantages
Can better protect the integrity and security of the
content and users of the network
Disadvantages
Directory servercan be slowed or overwhelmed by
too many users or technical problems
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Peer-to-Peer Network Diagrams
6-38
Telecommunications Media
Twisted-Pair Wire– Ordinary telephone wire– Copper wire is twisted into pairs
Coaxial Cable– Sturdy copper or aluminum wire
wrapped with spacers to insulateand protect it
Fiber-Optic Cable– One or more hair-thin filaments
of glass fiber wrapped in a protective jacket
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The Problem of “The Last Mile”
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
6-40
Wireless Technologies
TerrestrialMicrowave
Earthbound microwave systems transmit high-speed radio signals
Follows line-of-sight path between relay systems spaced about 30 miles apart
Communications Satellites
Serve as relay stations
Use microwave radio signals
Earth stations beam signals to the satellites
Not suitable for interactive, real-time processing
Telephone &Pager Systems
Geographic areas divided into cells
Each cell has low-power transmitter or radio relay antenna
Computers & other communications processors coordinate/control transmissions to/from mobile users
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Wireless Technologies
WirelessLANS
Uses wireless radio-wave technology to connect PCs within an office or building
Can be high-frequency (like digital cellular), or low frequency (spread spectrum)
Bluetooth
Short-range wireless
Connects PCs to peripheral devices
Fairly low cost to implement
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Wireless Technologies
Telecommunications networks nowplay vital and pervasive roles in…
Web-enabled e-business processes
Electronic commerce
Enterprise collaboration
Other applications that support businessoperations, management, & strategic objectives
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Communications Processors
• Modems
• Switch
• Router
• Hub
• Gateway