Telecommunications, Networks, Telecommunications, Networks, and the Internetand the Internet

Chapter Eight (9Chapter Eight (9thth ed) ed)

22

Chapter 8 and Our QuestionsChapter 8 and Our Questions

5. What is the role of the Internet and 5. What is the role of the Internet and networking technology in modern networking technology in modern organizations?organizations? Discuss networking concepts, Discuss networking concepts,

components, capabilities, and trends components, capabilities, and trends Distinguish among internets, intranets, Distinguish among internets, intranets,

extranetsextranets

33

Telecommunications and Telecommunications and Networking in Today’s Business Networking in Today’s Business

WorldWorld Prior to 1990 most business communicationPrior to 1990 most business communication

Postal servicePostal service Telephone system (voice & fax)Telephone system (voice & fax)

Today most business communication isToday most business communication is Computers and email using the InternetComputers and email using the Internet Cellular telephonesCellular telephones Mobile computers using wireless Mobile computers using wireless

connectionsconnections All business has become “e-business”All business has become “e-business”

44

Magnitude of the ChangeMagnitude of the Change

1 billion instant messages per day

4 billion e-mails each day

65 million music files downloaded Estimated 3.9 billion photos sent over the

Internet

$769 billion spent in the United States on telecommunications equipment and services

55

Telecommunications spending in the United States, 2002–2007

Note differences between services and equipment spending

66

The Business Telecommunications Environment

Today’s telecommunications environment provides communication channels for text, voice, and video images.

Today the network infrastructure for a large corporation consists of different kinds of networks for text, voice, and video images.

Most of these different kinds of networks are moving towards a common Internet foundation.

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Corporate Network InfrastructureCorporate Network Infrastructure

88

Pieces in the Corporate Pieces in the Corporate InfrastructureInfrastructure

Center piece is a collection of linked LANS that Center piece is a collection of linked LANS that support a firm wide corporate networksupport a firm wide corporate network

A series of servers supporting a corporate web A series of servers supporting a corporate web site linked to enterprise and legacy systemssite linked to enterprise and legacy systems

Support for a mobile sales forceSupport for a mobile sales force Separate telephone network (cell and landline)Separate telephone network (cell and landline) Separate video conferencing system (not Separate video conferencing system (not

shown)shown) Currently no one vendor can supply all of the Currently no one vendor can supply all of the

services requiredservices required How does a manager navigate through this How does a manager navigate through this

complex environment and make the right complex environment and make the right decisions?decisions?

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Seven Major Trends In Telecommunications

1. Proliferation of new hardware and new alternatives for business communications (Internet cell phones and wireless LANS)

2. Telecom deregulation continues to encourage competition and alternatives (e.g., DSL)

3. Distinctions between telephone, cable television, Internet, and satellite telecommunication are blurred.

4. Growing dominance of Internet technologies in voice, video, and data communications

5. Rapid growth in “last-mile” high-speed broadband connections to homes and businesses

6. Rapid growth in wireless telephone, wireless computer networks, and mobile Internet devices

7. Growing scope of communication-intense services and products (Internet telephone and telephone photography)

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Why Is Business Interested in Why Is Business Interested in Telecommunication and Telecommunication and

Networking?Networking? Declining transaction costs (benefits of B2C and

B2B) Declining agency costs because managers can

monitor employees and markets remotely Increased agility (connections with suppliers and

customers enables managers to spot trends and take appropriate actions). Concepts like extranets, collaborative commerce, intranets support this idea.

Higher quality management decisions (access to more information in a timely manner)

Declining geographical barriers Declining temporal barriers (software

development, time-based competition)

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Key Networking Infrastructure Key Networking Infrastructure ComponentsComponents

Basics – NIC, NOS, hub, switch, and routerBasics – NIC, NOS, hub, switch, and router Client/Server computingClient/Server computing Packet switchingPacket switching TCP/IP TCP/IP Signal typesSignal types Transmission speedsTransmission speeds Transmission media – wire or wirelessTransmission media – wire or wireless Types of networks – geographic scope or Types of networks – geographic scope or

shapeshape High-speed transmission technologiesHigh-speed transmission technologies

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Basic Network ComponentsBasic Network Components

A network consists of two or more connected computers.

A network interface device (NIC) is the connection point between one computer and the network

A network operating system (NOS) routes and manages communications on the network and coordinates network resources (saving or retrieving files on your hard drive versus a network drive)

1313

Basic Network Components Basic Network Components (continued)(continued)

Hubs connect network components, sending a packet of data to all other connected devices

A switch has more intelligence than a hub and can forward data to a specified device or destination. The switch is used within a given network to move information.

Unlike a switch, a router (bridge) is a special communications processor used to route packets of data through different networks, ensuring that the message sent gets to the correct address. A router connects a LAN to the Internet.

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A Simple NetworkA Simple Network

Figure 8-4

1515

Client/Server ComputingClient/Server Computing

The hardware sideThe hardware side The clientThe client The serverThe server

The software sideThe software side Client/server software splits the Client/server software splits the

processing of applications between the processing of applications between the client and server to take advantage of client and server to take advantage of strengths of each machinestrengths of each machine

E-mail and browsers are examplesE-mail and browsers are examples Client/server computing has largely Client/server computing has largely

replaced centralized mainframe computingreplaced centralized mainframe computing

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Packet SwitchingPacket Switching In packet-switched networks, messages are first

broken down into small bundles of data called packets that are sent along different communication paths and then reassembled once they reach their destinations.

Packet switching makes more efficient use of the communications capacity of a network.

The packets include information for directing the packet to the right address and for checking transmission errors along with the data.

Always done on the Internet, but restricted to data now being used for voice (VoIP)

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Packet SwitchingPacket Switching

Figure 8-5

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TCP/IPTCP/IP

• TCP/IP is the communications protocol used by the Internet and all Internet devices.

TCP partTCP part Handles the movement of data between

computers Establishes a connection between the

computers, sequences the transfer of packets, and acknowledges the packets sent

IP part Responsible for the delivery of packets Includes the disassembling and

reassembling of packets during transmission

1919

Data and SignalsData and Signals Digital data (1’s and 0’s) are represented by a Digital data (1’s and 0’s) are represented by a

discrete non-continuous wave form.discrete non-continuous wave form. Analog data is represented by a continuous wave Analog data is represented by a continuous wave

form. The human voice, music, and noise are form. The human voice, music, and noise are examples of analog data. examples of analog data.

From a physical point of view, data can converted to From a physical point of view, data can converted to an electric (carried over a wire) or electromagnetic an electric (carried over a wire) or electromagnetic (stream of photons) signal (stream of photons) signal

Usually digital signals convey digital data and Usually digital signals convey digital data and analog signals convey analog data. analog signals convey analog data.

In telecommunications there is a need to convert In telecommunications there is a need to convert digital data to an analog signal and vice versa. digital data to an analog signal and vice versa.

Computers emit digital data but parts of the Computers emit digital data but parts of the telephone system only transmit analog signals, so telephone system only transmit analog signals, so digital data must be converted into an analog signal digital data must be converted into an analog signal and vice versa (need for your modem) and vice versa (need for your modem)

2020

More on SignalsMore on Signals All signals can be represented as a sine wave All signals can be represented as a sine wave

(curve).(curve). The amplitude of a sine wave is the maximum height The amplitude of a sine wave is the maximum height

of the sine wave from the x-axisof the sine wave from the x-axis The frequency of a sine wave is the number of times The frequency of a sine wave is the number of times

a sine wave makes a complete cycle within a given a sine wave makes a complete cycle within a given time frame.time frame.

Cycles per second is referred to as Hertz (Hz)Cycles per second is referred to as Hertz (Hz) Digital data can be converted to a digital signal by Digital data can be converted to a digital signal by

using two different voltages.using two different voltages. Digital data can be converted to an analog signal by Digital data can be converted to an analog signal by

using either two different frequencies or two using either two different frequencies or two different amplitudes.different amplitudes.

The greater the frequency of a signal, the higher the The greater the frequency of a signal, the higher the possible data transfer rate; the higher the desired possible data transfer rate; the higher the desired data transfer rate, the greater the need signal data transfer rate, the greater the need signal frequency. frequency.

2121

Electromagnetic SignalsElectromagnetic Signals Electromagnetic signals can be described in Electromagnetic signals can be described in

terms of a stream of photons each traveling in terms of a stream of photons each traveling in a wave-like pattern, moving at the speed of a wave-like pattern, moving at the speed of light and carrying some amount of energy. light and carrying some amount of energy. The only difference between radio waves, The only difference between radio waves, visible light, and gamma-rays is the energy of visible light, and gamma-rays is the energy of the photons. Radio waves have photons with the photons. Radio waves have photons with low energies, microwaves have a little more low energies, microwaves have a little more energy than radio waves, infrared has still energy than radio waves, infrared has still more, then visible, X-rays, and gamma-rays. more, then visible, X-rays, and gamma-rays. Low energy photons (such as radio) behave Low energy photons (such as radio) behave more like waves, while higher energy photons more like waves, while higher energy photons (such as X-rays) behave more like particles. (such as X-rays) behave more like particles.

The electromagnetic spectrum can be The electromagnetic spectrum can be expressed in terms of energy, wavelength, or expressed in terms of energy, wavelength, or frequency. Each way of thinking about the EM frequency. Each way of thinking about the EM spectrum is related to the others in a precise spectrum is related to the others in a precise mathematical way (see next slide). mathematical way (see next slide).

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The Relationship Between Wave The Relationship Between Wave Length and FrequencyLength and Frequency

2323

ModulationModulation

Figure 6.8 Signal modulation

2424

Frequency Spectrum for Frequency Spectrum for Electromagnetic SignalsElectromagnetic Signals

All waves behave All waves behave similarlysimilarly

Frequency Frequency differencesdifferences Amount of dataAmount of data DistanceDistance Interference / Interference /

NoiseNoise

ELF VLF LF MF HF VHF UHF Microwave Optical

100 1K 100K 1M1M 10M 100M 1G 10G Hertz

Navy/s

ubm

arine

s

TV: 22

0M -

500

MHz

AM:

550K

- 16

50 K

Hz

Public

Saf

ety:

150

M -

160

MHz

Public

Saf

ety:

460

M -

500

MHz

Cellula

r pho

nes:

800

MHz

Cordle

ss p

hone

s (s

ome)

: 90

0 M

Hz

Pers.

Com

. Sys

(PCS):

1.8

5 G -

2.2

GHz

PCS E

T: 2

GHz

TV: 54

M -

216

MHz

FM:

88M

- 10

8 M

Hz

2525

Transmission SpeedsTransmission Speeds Digital signal speeds are usually expressed Digital signal speeds are usually expressed

in bits per second (Kbps, Mbps, and Gbps).in bits per second (Kbps, Mbps, and Gbps). Analog signal speeds are usually expressed Analog signal speeds are usually expressed

in frequency per second or Hertz (KHz, MHz, in frequency per second or Hertz (KHz, MHz, or GHz).or GHz).

A simple relationship between bps and A simple relationship between bps and frequency is found in Nyquist’s theorem frequency is found in Nyquist’s theorem C=2*f*(logC=2*f*(log22)*L where f is the frequency, L )*L where f is the frequency, L

is the number of signal levels (often 2) is the number of signal levels (often 2) and C is the capacity of the medium in bpsand C is the capacity of the medium in bps

The range of frequencies accommodated on The range of frequencies accommodated on a particular medium is called its bandwidth. a particular medium is called its bandwidth. For example, current cell phones operate in For example, current cell phones operate in a bandwidth between 1.85 GHz and 2.2 GHza bandwidth between 1.85 GHz and 2.2 GHz

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Transmission Media – Wire Or Transmission Media – Wire Or WirelessWireless

Wire mediaWire media Twisted Wire – up to 100Mbps Coaxial Cable – up to 1 Gbps Fiber Optics – up to 6+Tbps

Uses strands of glass and pulses of light

Most expansive of three – can carry data, voice, and video efficiently

Wireless media Terrestrial microwave 100 +Mbps Satellite microwave GEO (geostationary

earth orbit); about 22,000 miles above earth

Satellite microwave LEO (low earth orbit); about 400-1000 miles above earth

2727

Multiplexing ConceptMultiplexing Concept

Multiplexing involves using a single Multiplexing involves using a single communications channel to carry communications channel to carry simultaneous transmissions from multiple simultaneous transmissions from multiple sources.sources.

ExamplesExamples Frequency division multiplexing divides a Frequency division multiplexing divides a

high speed channel into multiple channels high speed channel into multiple channels of slower speedsof slower speeds

Time division multiplexing assigns the Time division multiplexing assigns the sender transmitter a small slice of time to sender transmitter a small slice of time to use the high speed channeluse the high speed channel

2828

Types of Networks by Geographic Types of Networks by Geographic ScopeScope

Type Area

Local Area Network (LAN) Up to 500 meters (half a mile); an office or floor of a building

Campus Area Network (CAN) Up to 1,000 meters (a mile); a college campus or corporate facility

Metropolitan Area Network (MAN)

A city or metropolitan area

Wide Area Network (WAN) Transcontinental or global area

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LANsLANs Typical LAN operating systems are Windows (based), Typical LAN operating systems are Windows (based),

Linux, or Novell each supports TCP/IP (ease of Linux, or Novell each supports TCP/IP (ease of establishing an intranet)establishing an intranet)

Ethernet is a LAN standard contained on the NICEthernet is a LAN standard contained on the NIC LANs may use the client-server or peer-to-peer LANs may use the client-server or peer-to-peer

architecture (all computers can share resources architecture (all computers can share resources directly)directly)

In the client-server modelIn the client-server model NOS is primarily on the serverNOS is primarily on the server Large LANs often have many servers each Large LANs often have many servers each

dedicated to a specific function (e.g., print server, dedicated to a specific function (e.g., print server, file server, Web server)file server, Web server)

LAN topologies (shapes)LAN topologies (shapes) StarStar BusBus RingRing

Wired LANs versus wireless LANsWired LANs versus wireless LANs

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LAN TopologiesLAN Topologies

3131

Unique Features of the InternetUnique Features of the Internet

3232

The Internet Addressing SystemThe Internet Addressing SystemEvery device connected to the Internet has a

unique 32-bit numeric IP address.

A Domain Name System (DNS) converts IP addresses to English-like domain names.

The domain name is the name that corresponds to the unique 32-bit numeric IP address for each computer connected to the Internet.

DNS servers maintain a database containing IP addresses mapped to their corresponding domain names.

To access a computer on the Internet, users need only specify its domain name.

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Limitations on the Addressing Limitations on the Addressing SystemSystem

Internet Protocol version 4 (IPv4): A 32-bit string of numbers organized into four sets of numbers ranging from 0 to 255; contains up to 4 billion addresses

Internet Protocol version 6 (IPv6): 128-bit addresses, contains over a quadrillion possible unique addresses

Internet2 and Next-Generation Internet (NGI) are consortia working on the next generation

3434

Internet GovernanceInternet Governance

• No one “owns” the Internet, but

worldwide Internet policies are established

by the following organizations: Internet Architecture Board (IAB) Internet Corporation for Assigned

Names and Numbers (ICANN) Internet Network Information Center

(InterNIC) Internet Engineering Steering Group

(IESG) Internet Engineering Task Force (IETF) Internet Society (ISOC) World Wide Web Consortium (W3C)

3535

Internet Technologies with Internet Technologies with Business ImplicationsBusiness Implications

Chatting and instant messagingChatting and instant messaging Electronic discussion groupsElectronic discussion groups GroupwareGroupware Electronic conferencingElectronic conferencing Internet telephonyInternet telephony Virtual private networksVirtual private networks

3636

Management Opportunities Management Opportunities

• Firms have opportunities to radically reduce

the cost of communicating with their

employees, vendors, and customers. There

are many new opportunities to develop new

business models based on the new

telecommunications technologies.

3737

Management ChallengesManagement Challenges

Loss of management controlLoss of management control Distributed resources are harder to controlDistributed resources are harder to control Employees have independent sources of Employees have independent sources of

computing powercomputing power Use of technology for non-business purposesUse of technology for non-business purposes

Organizational changes must take place as Organizational changes must take place as firms embrace new technologiesfirms embrace new technologies Polices for handling dataPolices for handling data

Reliability and security Reliability and security