7 - telecom, internet & wireless tech

7Chapter

Telecommunications, the

Internet, and Wireless

Technology

LEARNING OBJECTIVES

• Identify the principal components of telecommunications

networks and key networking technologies.

• Describe the main telecommunications transmission media

and types of networks.

• Explain how the Internet and Internet technology work and

how they support communication and e-business.

• Identify the principal technologies and standards for

wireless networking, communication, and Internet access.

• Assess the value to business of radio frequency

identification (RFID) and wireless sensor networks.

Management Information SystemsChapter 7 Telecommunications, the Internet, and Wireless Technology

Virgin Megastores Keeps Spinning with Unified Communications

• Problem: 1400 employees in 11 retail locations; slow resolutions of business issues because of cost of conference calls

• Solutions: Implement unified communications to integrate voice mail, e-mail, conference calling, instant messaging

• Microsoft’s Office Communication Server, Office

Communicator, RoundTable conferencing and

collaboration tools

• Demonstrates IT’s role in hastening communication

and flow of information


Telecommunications and Networking in Today’s Business World

• Networking and communication trends

• Convergence:

• Telephone networks and computer networks converging

into single digital network using Internet standards

• Cable companies providing voice service

• Broadband:

• More than 60% of U.S. Internet users have broadband

access

• Broadband wireless:

• Voice and data communication as well as Internet access

are increasingly taking place over broadband wireless

platforms


Components of data communication

What is Data ?

• Data is a collection of facts, such as values or measurements.

• It can be numbers, words, measurements, observations or even

just descriptions of things.

• Data can exist in a variety of forms -- as numbers or text on

pieces of paper, as bits and bytes stored in electronic memory,

or as facts stored in a person's mind.

• Data is the plural of datum, a single piece of information.

DATA COMMUNICATION

Data communication is the transfer of information between two points, either

via an analogue (sine wave) electrical signal or digital (binary ) signal via

electrical pulses or optically via light pulses.

High speed data exchange between computers and/or other

electronic devices via cable or wireless.

Data Transmission Modes

There are three modes of transmitting data fromone point to another. These are :

• Simplex

• Half-duplex OR

• Full-duplex

AND

SenderReceiv

er

Sender(or

Receiver)

Receiver(or

Sender)

Sender(and

Receiver)

Receiver(and

Sender)

COMPONENTS

The main components of data communication system are:

• Message

• Sender

• Receiver

• Medium

MESSAGE

• Message may exist in several different forms. It could be sound, light, picture, text, video etc.

• A message is information which is sent from a source to a receiver.

Transmitter

A transmitter is the agent, which could be a

human or a machine, that actually wishes to

transmit the data/ information to a recipient is

called the transmitter or sender.

Receiver

Receiver is the component that collects the coded message

from the communication channel. This piece of data is still not

in the form of the original message.

Medium

Once signal corresponding to the message is obtained, an end-

to-end medium is required through which the signal may travel

from the sender to the other end.

Transmission Medium

• Provides the path for data communication.

• Allows a bit stream to be transported from one machine to another.

Twisted Pair Cable

Coaxial Cable

Optical Fiber Cable

MEDIA ADVANTAGES DISADVANTAGES

Twisted Pair Cables

Coaxial Cable

Optical Fiber Cable

Inexpensive, wellestablished.

High bandwidth, long distances.

Very high bandwidth, long distances, high security,

small size.

Sensitive to noise, short distances, security hazard because of easy

interception.

Security is better in comparison to twisted

pair cable.

Connections Cost.

• What is a computer network?

• Two or more connected computers

• Major components in simple network

• Client computer

• Server computer

• Network interfaces (NICs)

• Connection medium

• Network operating system

• Hub or switch

• Router



Components of a Simple Computer Network

Figure 7-1

Illustrated here is a very simple computer network, consisting of

computers, a network operating system residing on a dedicated

server computer, cabling (wiring) connecting the devices, network

interface cards (NIC), switches, and a router.



What is a Computer Network?

A network is a collection of computers, printers, routers, switches, and other

devices that are able to communicate with each other over some

transmission media.

Types of Networks

There are two basic types of networks currently in existence:

A Local Area Network (LAN)

A Wide Area Network (WAN)

Local Area

Networks

(LAN)A Local Area Network (LAN) is a group of computers and

network communication devices within a limited geographic area,

such as an office building. No third party involvement here.

They are characterized by the following:

• High data transfer speeds

• Generally less expensive technologies

• Limited geographic area

Wide Area

Networks

(WAN) A Wide Area Network (WAN) interconnects LANs. It is not

restricted to a particular geographic area and may be

interconnected around the world. Third party network is involved.

They are characterized by the following:

• Multiple interconnected LANs

• Generally more expensive technology

• More sophisticated to implement than LANs

• Exist in an unlimited geographic area

• Less error resistance due to transmission travel distances

Common LAN Topologies

Bus Architecture In a bus topology:

• a single cable connects each

workstation in a linear, daisy-chained

fashion.

•signals are broadcasted to all

stations, but stations only act on the

frames addressed to them.

Ring Architecture•In a ring topology:

•Unidirectional links connect the

transmit side of one device to the

receive side of another device.

•Devices transmit frames to the next

device (downstream member) in the

ring.

Star Topology

In a star topology, each station is connected to a central

hub or concentrator that functions as a multi-port

repeater. Each station broadcasts to all of the devices

connected to the hub. Physical LAN topologies are

usually characterized as either bus or ring.

LAN Transmission Methods

LAN transmission methods fall into 3 main categories:

• Unicast transmission

• Multicast transmission

• Broadcast transmission

Unicast Transmission

Unicast Process

• The source addresses

the packet with the

destination address.

• The packet is sent into

the network.

• The network delivers the

packet to the destination.

In unicast transmissions, a single data packet is sent from a source to a

single destination on the network.

Multicast Transmission

Multicast Process

• The source addresses the packet

using a multicast address.

• The packet is sent into the

network.

• The network copies the packet.

• A copy is delivered to each

destination that is included in the

multicast address.

In multicast transmissions, a single data packet is copied and sent to

specific destinations on the network

Broadcast Tranmission

In Broadcast transmissions, a single data packet is copied and sent to all

destinations on the network

Broadcast Process

• The source addresses the packet with the broadcast address.

• The packet is sent into the network.

• The network copies the packet.

• The packet copies are delivered to all destinations on the

network.

Uses of Computer Networks

• Resource Sharing: Many organizations have large number ofsubstantial computers in operation often located far apart. Letus consider an example, a company having many factoriessituated at different locations. A computer at each location(that is in each factory) keeps the track of inventories, monitorproductivity and do the local pay roll. Initially each of thesecomputers may have worked in isolation from each other, butat some point, the management may have decided to connectthese computers to be able to extract and correlate theinformation of the entire company.

The issue here is resource sharing. Its goal is to make all theprograms, equipments, especially data available to anyone onthe network irrespective of the location of the resource andthe user.

• High Reliability: The second goal or use ofnetworking in companies is to high reliability byhaving alternative sources of supply. For example allthe files can be replicated on two or more machines,so that in case one of them is not available (due tohardware failure), other copies can be used. Thisfeature is used in financial institutions.

• Scalability: Another goal is scalability. Scalability isthe ability to increase the system performancegradually as the workload grows, by just adding moreprocessors.

• Saving Money: The third goal is to save money. Smallcomputers often have better price/performance ratiothan the larger ones. Mainframe (room-size) computersare roughly ten times faster than the personalcomputers, but are a thousand times costly. Thisimbalance caused the system designers to design asystem consisting of personal computers, one per user,with data kept on one or more shared file servermachines. In this model the user are called the clientsand this whole arrangement is known as the client-servermodel.

In client-server model, the communication generallytakes the form of a request message from a client to thereceiver asking for some work to be done. Server doesthe work and sends back the reply.

• Access to Remote Information: Access to remoteinformation occurs in many forms. One of the areaswhere it is happening is access to the financialinstitutions. Many people pay their bills, managebank accounts and handle investments electronically.Home shopping is also becoming popular these days.

Another application that falls under this category isthe access to information systems like World WideWeb which contains information about art, business,history, government, geography, economics andseveral other topics.

All the above applications involve the interactionbetween the user and a remote database.

• Person to Person Communication: Electronic Mailpopularly known as email is widely used by millionsof people to send text messages, photographs audioas well as video to other people or group of people.This application belongs to person to personcommunication category.

Videoconferencing is also becoming popular thesedays. This technology makes it possible to havevirtual meetings among far flung people. It is also atype of person to person communication.

• Interactive Entertainment: These days we cansee many live programmes and shows. Thebest thing is that we can interact with them byparticipating in the quizzes and the contestsorganized by them.

• File sharing: Have you ever needed to access afile stored on another computer? A networkmakes it easy for everyone to access the samefile and prevents people from accidentallycreating different versions.

• Printer sharing: If you use a computer, chances areyou also use a printer. With a network, severalcomputers can share the same printer. Although youmight need a more expensive printer to handle theadded workload, it's still cheaper to use a networkprinter than to connect a separate printer to everycomputer in your office.

• Communication and collaboration: It's hard forpeople to work together if no one knows whatanyone else is doing. A network allows employees toshare files, view other people's work, and exchangeideas more efficiently. In a larger office, you can usee-mail and instant messaging tools to communicatequickly and to store messages for future reference.

• Organization: A variety of scheduling softwareis available that makes it possible to arrangemeetings without constantly checkingeveryone's schedules. This software usuallyincludes other helpful features, such as sharedaddress books and to-do lists.

Networking Hardware

• NICs

• Repeaters and Hubs

• Switches

• Routers

• Bridges

• Brouter

• Gateway

• Modems

• ISDN Adaptors

• CSU/DSU

• Network Example

NICs

• Network interface cards (also called NICs, network adapters,LAN Card or network cards) are connectivity devices thatenable a workstation, server, printer, or other node toreceive and transmit data over the network media.

• Nearly all NICs contain a data transceiver, the device thattransmits and receives data signals.

• NICs belong to both the Physical layer and Data Link layer ofthe OSI Model, because they apply data signals to the wireand assemble or disassemble data frames.

• In addition, they perform the routines that determine whichnode has the right to transmit data over a network at anygiven instant

Repeaters and Hubs

• Repeaters operate in the Physical layer of the OSI Modeland, therefore, have no means to interpret the data theyretransmit.

• They simply regenerate a signal over an entire segment.

• A repeater contains one input port and one output port,so it is capable only of receiving and repeating a datastream

• Repeaters are suited only to bus topology networks

• The advantage to using a repeater is that it allows you toextend a network inexpensively

Repeaters and Hubs

• A hub is a repeater with more than one output port.

• A hub typically contains multiple data ports intowhich the patch cables for network nodes areconnected.

• A hub accepts signals from a transmitting node andrepeats those signals to all other connected nodes ina broadcast fashion

Switches

• Switches are connectivity devices thatsubdivide a network into smaller logicalpieces, or segments.

• Switches operate at the Data Link layer of theOSI Model, while more modern switches canoperate at Layer 3 or even Layer 4.

• Switches interpret MAC address information

• Because they have multiple ports, switches canmake better use of limited bandwidth.

• Each device connected to a switch effectivelyreceives its own dedicated channel to the switch.

• From the Ethernet perspective, each dedicatedchannel represents a collision domain.

• Because a switch limits the number of devices in acollision domain, it limits the potential for collisions.

• By their nature switches provide better security thanmany other devices because they isolate onedevice's traffic from other device’s traffic

• Connecting a workstation to a switch

• A switch on a small network

Switches Contd….

• Switches differ in the method of switching they use:1. Cut-through mode2. Store and forward mode

Cut-Through Mode

• A switch running in cut-through mode reads a frame's headerand decides where to forward the data before it receives theentire packet.

• What if the frame becomes corrupt? Because the cut-through mode does not allow the switch to read the framecheck sequence (FCS) before it begins transmitting, it can'tverify data integrity in that way.

Store and Forward Mode

• In store and forward mode, a switch reads the entiredata frame into its memory and checks it foraccuracy before transmitting the information.

• Although this method is more time-consuming thanthe cut- through method, it allows store and forwardswitches to transmit data more accurately.

• Store and forward mode switches are moreappropriate for larger LAN environments, becausethey do not propagate data errors.

Routers

• A router is a multiport connectivity device thatdirects data between nodes on a network.

• Routers can integrate LANs and WANs running atdifferent transmission speeds and using a variety ofprotocols.

• When a router receives an incoming packet, it readsthe packet's logical addressing information.– Based on this, it determines to which network the packet

must be delivered.– Then it determines the shortest path to that network.– Finally it forwards the packet to the next hop in that path.

• A router's strength lies in its intelligence.

• Not only can routers keep track of thelocations of certain nodes on the network, asswitches can, but they can also determine theshortest, fastest path between two nodes.

• For this reason, and because they can connectdissimilar network types, routers arepowerful, indispensable devices on largeLANs and WANs.

• The Internet, for example, relies on amultitude of routers across the world

• A typical router has an internal processor, an operatingsystem, memory, input and output jacks for different types ofnetwork connectors (depending on the network type), and,usually, a management console interface.

Hub versus Switch

• Hub provide connection to all ports (i.e. in oneport and out all other ports).– Passive hub – no signal regeneration

– Active hub – provide signal regeneration

• Switch direct the message from appropriateport (directs a message from the input port tothe desired output port).– More expensive but better bandwidth utilization

Hub versus Switch

Bridge

• Connects two LAN segments to make one largercontinuous LAN

• Filters LAN traffic to keep local traffic.

• Allows connectivity to other parts of the LAN

• Simple to install and manage—costs less than router

• Checks MAC address to make forwarding decisions

• Considered layer 2 device

Bridge – Access Point (WLAN)

Brouter

• Network bridge and router combinedtogether to form a device known asbrouter.

Gateway• A gateway is a network point that acts as an entrance to

another network. On the Internet, a node or stopping pointcan be either a gateway node or a host (end-point) node. Boththe computers of Internet users and the computers that servepages to users are host nodes, while the nodes that connectthe networks in between are gateways. For example, thecomputers that control traffic between company networks orthe computers used by internet service providers (ISPs) toconnect users to the internet are gateway nodes.

• In the network for an enterprise, a computer server acting asa gateway node is often also acting as a proxy server and afirewall server. A gateway is often associated with both arouter, which knows where to direct a given packet of datathat arrives at the gateway, and a switch, which furnishes theactual path in and out of the gateway for a given packet.

Modem

• Allows modems of different vendors tooperate together

• Define How modems operate:

– Modulation techniques

– Data compression technique

– Error detection strategy

– Parallel to Serial and vice versa

• Analog

– Infinite number of levels

– Conform to voice pattern

– Times from highest to lowest and back to the highest point in one second is the frequency

– Can be transmitted over long distance

• Digital

– Only two levels (high and low)

– Conforms to how computers operate

– Cannot transmitted over long distance

Modem - Connection

Modem – Internal/External

ISDN Adaptors

• ISDN (Integrated Services Digital Network) is a datacommunication method and it is used over theregular telephone lines. To use the ISDN lines, youneed to install add-on adapters known as ISDNterminal adapters. ISDN Terminal Adapter works likea digital modem i.e. it converts the signals fromdigital to analog and vice versa. ISDN Terminaladapter is plugged into the serial port of thesystem. Some ISDN adapters have the feature ofswitching between digital and analog modes.

CSU/DSU

• CSU/DSU stands for channel service unit and dataservice unit. CSU is used to connect a terminal to adigital line. DSU is used to perform the protectiveand diagnostic functions of the telecommunicationline. CSU/DSU is a network device of the size of anexternal modem. The Channel service unit receivesand transmits the signals from the wide areanetwork line. CSU/DSU are two separate devices andthey are sometimes used in conjunction with the T1LAN cards.

Network Example

Network Software• Network Software is a set of primitives that define the protocol

between two machines. The network software resolves an ambiguityamong different types of network making it possible for all themachines in the network to connect and communicate with oneanother and share information.

• Network software is the information, data or programming used tomake it possible for computers to communicate or connect to oneanother.

• Network software is used to efficiently share information amongcomputers. It encloses the information to be sent in a “package” thatcontains a “header” and a “trailer”. The header and trailer containinformation for the receiving computer, such as the address of thatcomputer and how the information package is coded. Information istransferred between computers as either electrical signals in electricwires, as light signals in fiber-optic cables, or as electromagnetic wavesthrough space.

Networks provide computer users aconvenient way to transfer files acrossdata connections. Secured networksrequire a user name and password inorder to connect your computer to thenetwork. Unsecured networks do notneed any authentication. All types ofnetworks need software to interface withthe network and begin communicationand data transfer.

• Home Software : Setting up a network using the Ciscosoftware Network Magic Pro is easy; the software wasprogrammed with novice computer users in mind. Tasks suchas creating secured Internet connections, sharing digitaldevices such as cameras and printers and monitoring Webaccess are all controlled through the software's maininterface. This software is ideal for entry-level computerusers.

• Free Software : Spiceworks provides a budget-friendly optionfor individuals who want a network management softwarepackage. The software is free and offers many of the samefeatures as other software packages available for sale. Thissoftware package was intended to be used within small tomedium sized businesses. The few of the key features are theability to inventory everything on your network, run an ITHelpdesk and Map the Network.

• Monitoring Tools : Networks are often damaged from burntpower supplies, servers crashing, low bandwidth and evenattacks from computer hackers. Computer hackers are expertsin network administration, but the appropriate software willstop hackers dead in their tracks. The software Monitor Toolsprovides a central location to monitor and maintain all thesepotential trouble spots. The software will tell you of possiblesystem issues and provide quick suggestions for the resolutionof each problem as it arises.

• Application Performance : Network administrators aresometimes charged with the sole task of monitoringapplication performance, for example, making sure that filesare sent immediately and are successfully delivered on thereceiving end. Orion APM is a software package that focusesexclusively on application monitoring, ensuring all networksystems are running as quickly as possible.

• Warning : Choosing to set up a security system foryour wireless network is a decision to be takenseriously. A wireless network places your computerfiles at the fingertips of anyone within the broadcastrange of your wireless router. Personal informationsuch as Social Security numbers and credit cardsshould always be stored behind the protection ofcertified network security software. Once yournetwork is set up, and your files are secured, routinebackups of any important files should be createdonto hard drives, DVDs or other external storagemedium. The only way to be absolutely certain yourfiles are safe is to have a hard copy stored outsidethe network; if the network fails and data is lost, youwill be certain your important files are still safe.

Network Model Overview

In order for a computer to send information to another computer, and for that

computer to receive and understand the information, there has to exist a set

of rules or standards for this communication process. These standards

ensure that varying devices and products can communicate with each other

over any network. This set of standards is called a model.

Network Model Advantages

This division provides advantages for the network design, architecture and

implementation. These include:

Reduces complexity - by dividing the processes into groups, or layers,

implementation of network architecture is less complex

•Provides compatibility - standardized interfaces allow for "plug-and-play"

compatibility and multi-vendor integration

•Facilitates modularization - developers "swap" out new technologies at

each layer keeping the integrity of the network architecture

•Accelerates evolution of technology - developers focus on technology at

one layer while preventing the changes from affecting another layer

•Simplifies learning - processes broken up into groups divides the

complexities into smaller, manageable chunks

• Networks in large companies

• Components can include:

• Hundreds of local area networks (LANs) linked to firmwide

corporate network

• Various powerful servers

• Web site

• Corporate intranet, extranet

• Backend systems

• Mobile wireless LANs (Wi-Fi networks)

• Videoconferencing system

• Telephone network

• Wireless cell phones



Corporate Network Infrastructure

Figure 7-2Today’s corporate network

infrastructure is a collection of

many different networks from the

public switched telephone

network, to the Internet, to

corporate local area networks

linking workgroups, departments,

or office floors.



• Key digital networking technologies

• Client/server computing

• Distributed computing model

• Clients linked through network controlled by network

server computer

• Server sets rules of communication for network and

provides every client with an address so others can find it

on the network

• Has largely replaced centralized mainframe computing

• The Internet: Largest implementation of client/server

computing



• Packet switching

• Method of slicing digital messages into parcels (packets),

sending packets along different communication paths as

they become available, and then reassembling packets at

destination

• Previous circuit-switched networks required assembly of

complete point-to-point circuit

• Packet switching more efficient use of network’s

communications capacity



Packet-Switched Networks and Packet Communications

Figure 7-3Data are grouped into small packets,

which are transmitted independently over

various Communications channels and

reassembled at their final destination.



• TCP/IP and connectivity

• Connectivity between computers enabled by protocols

• Protocols: Rules that govern transmission of information

between two points

• Transmission Control Protocol/Internet Protocol

(TCP/IP)

• Common worldwide standard that is basis for Internet

• Department of Defense reference model for TCP/IP

• Four layers

• Application layer

• Transport layer

• Internet layer

• Network interface layer



The Transmission Control Protocol/Internet

Protocol (TCP/IP) Reference Model

Figure 7-4This figure illustrates the four layers of the

TCP/IP reference model for communications.



OSI Network Model

There are 7 layers in the OSI

model. Each layer is

responsible for a particular

aspect of data communication.

For example, one layer may be

responsible for establishing

connections between devices,

while another layer may be

responsible for error checking

during transfer.

The layers of the OSI model are divided into two groups: the upper layer

and lower layer. The upper layers focus on user applications and how files

are represented on the computers prior to transport. For the most part,

network engineers are more concerned with the lower layers. It's the lower

layers that concentrate on how the communication across a network

actually occurs.

ALL People Seem to Need Data Processing (Layer 7 to 1)

Please Do Not Take Sausage Pizzas Away (Layer 1 to 7)

The Application Layer

The Application Layer is the highest layer in the

protocol stack and the layer responsible for

introducing data into the OSI stack. In it resides the

protocols for user applications that incorporate the

components of network applications.

Classification of ApplicationsComputer applications

Network applications

Internetwork applications

Examples: Telnet, FTP, HTTP, WWW Browsers, NFS,

SMTP, POP, TFTP .

Presentation Layer

The Presentation Layer manipulates the

representation of data for transfer to applications on

different devices.

The Presentation Layer is responsible for the

following services:

• Data representation

• Data security

• Data compression

Data Representation

Session Layer

The Session Layer establishes, manages, and

terminates sessions (different from connections) between

applications as they interact on different hosts on a

network.

Its main job is to coordinate the service requests and

responses between different hosts for applications.

Examples: NFS, SQL, RPC, ASP

Three different communication modes exists for data

transfer within a session connection:

• Single-duplex

• Half-duplex

• Full-duplex.

2.80

Figure 2.1 Tasks involved in sending a letter

What do the 7 layers really do?

• Signals: digital vs. analog

• Modem: Translates digital signals into analog form

• Types of networks

• Local-area networks (LANs)

• Client/server or peer-to-peer

• Ethernet – physical network standard

• Topologies: star, bus, ring

• Campus-area networks (CANs)

• Wide-area networks (WANs)

• Metropolitan-area networks (MANs)

Communications Networks


Functions of the Modem

Figure 7-5

A modem is a device that translates digital signals from a computer into analog form so that they can be transmitted over

analog telephone lines. The modem also translates analog signals back into digital form for the receiving computer.



Network Topologies

Figure 7-6The three basic network

topologies are the bus,

star, and ring.



• Physical transmission media

• Twisted wire (modems)

• Coaxial cable

• Fiber optics and optical networks

• Wireless transmission media and devices

• Microwave

• Satellites

• Cellular telephones

• Transmission speed

• Hertz

• Bandwidth



BP Amoco’s Satellite Transmission System

Figure 7-7Communication satellites

help BP Amoco transfer

seismic data between oil

exploration ships and

research centers in the

United States.



• What is the Internet?

• Connecting to the Internet

• Internet service providers (ISPs)

• Services

• DSL, cable, satellite, T lines (T1, T3)

• Internet addressing and architecture

• IP addresses

• The domain name system

• Hierarchical structure

• Top-level domains

The Global Internet


The Domain Name System

Figure 7-8The Domain Name System is a

hierarchical system with a root

domain, top-level domains,

second-level domains, and host

computers at the third level.


The Global Internet

• Internet Architecture

• Trunk lines (backbone networks)

• Regional networks

• ISPs

• Internet Governance

• No formal management

• Policies established by professional, government organizations

• IAB, ICANN, W3C

• The Future Internet

• IPv6

• Internet2, NGI

The Global Internet


Internet Network Architecture

Figure 7-9The Internet backbone connects

to regional networks, which in

turn provide access to Internet

service providers, large firms,

and government institutions.

Network access points (NAPs)

and metropolitan area

exchanges (MAEs) are hubs

where the backbone intersects

regional and local networks and

where backbone owners connect

with one another.


The Global Internet

• Read the Interactive Session: Organization and then

discuss the following questions:

• What is network neutrality? Why has the Internet operated

under net neutrality up to this point in time?

• Who’s in favor of network neutrality? Who’s opposed?

Why?

• What would be the impact on individual users, businesses,

and government if Internet providers switched to a tiered

service model?

• Are you in favor of legislation enforcing network

neutrality? Why or why not?

Should Network Neutrality Continue?


The Wireless Revolution

• Internet services

• E-mail

• Chatting and instant messaging

• Newsgroups

• Telnet

• File Transfer Protocol (FTP)

• World Wide Web

• Voice over IP (VoIP)

• Unified communications

• Virtual private networks (VPNs)


The Global Internet

Client/Server Computing on the Internet

Figure 7-10Client computers running Web

browser and other software can

access an array of services on servers

over the Internet. These services may

all run on a single server or on

multiple specialized servers.


The Global Internet

• Read the Interactive Session: Management and

then discuss the following questions:

• Should managers monitor employee e-mail and Internet

usage? Why or why not?

• Describe an effective e-mail and Web use policy for a

company.

Monitoring Employees on Networks: Unethical or Good Business?


The Global Internet

How Voice over IP Works

Figure 7-11

An VoIP phone call digitizes and breaks up a voice message into data packets that may travel along different routes before

being reassembled at the final destination. A processor nearest the call’s destination, called a gateway, arranges the packets

in the proper order and directs them to the telephone number of the receiver or the IP address of the receiving computer.


The Global Internet

A Virtual Private Network Using the Internet

Figure 7-12

This VPN is a private network of computers linked using a secure “tunnel” connection over the Internet. It protects data transmitted

over the public Internet by encoding the data and “wrapping” them within the Internet Protocol (IP). By adding a wrapper around a

network message to hide its content, organizations can create a private connection that travels through the public Internet.


The Global Internet

• The World Wide Web

• HTML (Hypertext Markup Language):

• Formats documents for display on Web

• Hypertext Transfer Protocol (HTTP):

• Communications standard used for transferring Web

pages

• Uniform resource locators (URLs):

• Addresses of Web pages

• E.g.,

http://www.megacorp.com/content/features/082602.html

• Web servers

• Software for locating and managing Web pages


The Global Internet

• Search engines

• Started in early 1990s as relatively simple software programs

using keyword indexes

• Today, major source of Internet advertising revenue via

search engine marketing, using complex algorithms and

page ranking techniques to locate results

• Sponsored links vs. organic search results

• Shopping bots

• Use intelligent agent software for searching Internet for

shopping information


The Global Internet

How Google Works

Figure 7-13The Google search engine is

continuously crawling the

Web, indexing the content of

each page, calculating its

popularity, and storing the

pages so that it can respond

quickly to user requests to

see a page. The entire

process takes about one-half

second.


The Global Internet

Major Web Search Engines

Figure 7-14Google is the most popular search

engine on the Web, handling 56 percent

of all Web searches.


The Global Internet

• Web 2.0

• Second-generation interactive Internet-based services enabling

people to collaborate, share information, and create new

services online

• Cloud computing

• Software mashups and widgets

• Blogs: Chronological, informal Web sites created by

individuals using easy-to-use weblog publishing tools

• RSS (Really Simple Syndication): Syndicates Web content

so aggregator software can pull content for use in another

setting or viewing later

• Wikis: Collaborative Web sites where visitors can add, delete,

or modify content on the site


The Global Internet

• Web 3.0

• Current efforts to make using Web more productive

• Inefficiency of current search engines: Of 330 million

search engine queries daily, how many are fruitful?

• Semantic Web

• Collaborative effort to add layer of meaning on top of

Web, to reduce the amount of human involvement in

searching for and processing Web information

• Other, more modest views of future Web

• Increase in cloud computing, SaaS

• Ubiquitous connectivity between mobile and other

access devices

• Make Web a more seamless experience


The Global Internet

• Intranets

• Use existing network infrastructure with Internet connectivity

standards software developed for the Web

• Create networked applications that can run on many types of

computers

• Protected by firewalls

• Extranets

• Allow authorized vendors and customers access to an internal

intranet

• Used for collaboration

• Also subject to firewall protection


The Global Internet

• Wireless devices

• PDAs, BlackBerry, smart phones

• Cellular systems

• Competing standards for cellular service

• United States: CDMA

• Most of rest of world: GSM

• Third-generation (3G) networks

• Higher transmission speeds suitable for broadband Internet

access



• Wireless computer networks and Internet access

• Bluetooth (802.15)

• Links up to 8 devices in 10-m area using low-power, radio-

based communication

• Useful for personal networking (PANs)

• Wi-Fi (802.11)

• Set of standards: 802.11a, 802.11b, 802.11g, 802.11n

• Used for wireless LAN and wireless Internet access

• Use access points: Device with radio receiver/transmitter

for connecting wireless devices to a wired LAN



A Bluetooth Network (PAN)

Figure 7-15Bluetooth enables a variety

of devices, including cell

phones, PDAs, wireless

keyboards and mice, PCs,

and printers, to interact

wirelessly with each other

within a small 30-foot (10-

meter) area. In addition to

the links shown, Bluetooth

can be used to network

similar devices to send data

from one PC to another, for

example.



An 802.11 Wireless LAN

Figure 7-16Mobile laptop computers equipped with

wireless network interface cards link to

the wired LAN by communicating with

the access point. The access point uses

radio waves to transmit network signals

from the wired network to the client

adapters, which convert them into data

that the mobile device can understand.

The client adapter then transmits the

data from the mobile device back to the

access point, which forwards the data

to the wired network.



• Wireless computer networks and Internet access

• Wi-Fi (cont.)

• Hotspots: One or more access points in public place to

provide maximum wireless coverage for a specific area

• Weak security features

• WiMax (802.16)

• Wireless access range of 31 miles

• Require WiMax antennas

• Sprint Nextel building WiMax network



• Radio frequency identification (RFID)

• Use tiny tags with embedded microchips containing data

about an item and location, and antenna

• Tags transmit radio signals over short distances to special

RFID readers, which send data over network to computer for

processing

• Active RFID: Tags have batteries, data can be rewritten,

range is hundreds of feet, more expensive

• Passive RFID: Range is shorter, also smaller, less

expensive, powered by radio frequency energy



• Radio frequency identification (RFID)

• Common uses:

• Automated toll-collection

• Tracking goods in a supply chain

• Requires companies to have special hardware and software

• Reduction in cost of tags making RFID viable for many firms



How RFID Works

Figure 7-17

RFID uses low-powered radio transmitters to

read data stored in a tag at distances ranging

from 1 inch to 100 feet. The reader captures the

data from the tag and sends them over a

network to a host computer for processing.



• Wireless sensor networks

• Networks of hundreds or thousands of interconnected wireless

devices embedded into physical environment to provide

measurements of many points over large spaces

• Used to monitor building security, detect hazardous substances

in air, monitor environmental changes, traffic, or military activity

• Devices have built-in processing, storage, and radio frequency

sensors and antennas

• Require low-power, long-lasting batteries and ability to endure in

the field without maintenance



A Wireless Sensor Network

Figure 7-18The small circles represent

lower-level nodes and the larger

circles represent high-end

nodes. Lower-level nodes

forward data to each other or to

higher-level nodes, which

transmit data more rapidly and

speed up network performance.

