Telecommunications and Networks Chapter 6 Copyright © 2010 by the McGraw-Hill Companies, Inc. All...

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…

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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

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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

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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

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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

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Extranet Connectivity and Value

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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

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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

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Virtual Private Network

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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

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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

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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

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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