Mgt 20600: Mgt 20600: IT Management & ApplicationsIT Management & Applications

Telecommuncations and NetworksTelecommuncations and Networks

TuesdayTuesday

March 28, 2006March 28, 2006

RemindersReminders ReadingReading

– For todayFor today Fundamentals text, Chapter Four, Fundamentals text, Chapter Four,

Telecommunications chapterTelecommunications chapter– For next class on April 4thFor next class on April 4th

Fundamentals text, Chapter Three, Organizing Data Fundamentals text, Chapter Three, Organizing Data and Informationand Information

HomeworkHomework– Homework ThreeHomework Three

Networks and TelecommunicationsNetworks and Telecommunications Due Friday, March 31Due Friday, March 31stst

Will need to use outside resources to answer several Will need to use outside resources to answer several questionsquestions

Next week: DatabasesNext week: Databases

Networking and Networking and TelecommunicationsTelecommunications

Effective communications are Effective communications are essential to organizational successessential to organizational success

Why?Why?– Business processes are supported by Business processes are supported by

software that runs over networkssoftware that runs over networks– Must choose right software to support Must choose right software to support

business, then design the right network business, then design the right network to support the operation of the softwareto support the operation of the software

– Processing model will help determine Processing model will help determine what kind of network you needwhat kind of network you need

Basic Processing StrategiesBasic Processing Strategies

Centralized processing: Centralized processing: all all processing occurs in a single location processing occurs in a single location or facilityor facility

Decentralized processing: Decentralized processing: processing devices are placed at processing devices are placed at various remote locationsvarious remote locations

Distributed processing: Distributed processing: computers computers are placed at remote locations but are placed at remote locations but connected to each other via a networkconnected to each other via a network

Distributed Processing OptionsDistributed Processing Options

Terminal-to-host: Terminal-to-host: the application and database the application and database reside on one host computer, and the user reside on one host computer, and the user interacts with the application and data using a interacts with the application and data using a “dumb” terminal“dumb” terminal

Distributed Processing OptionsDistributed Processing Options

File or Application Server: File or Application Server: the the application or database reside on the one application or database reside on the one host computer, called the file serverhost computer, called the file server

Distributed Processing OptionsDistributed Processing Options

Client/ServerClient/Server

Client: End-user’s computerClient: End-user’s computer PC, mobile device, thin clientPC, mobile device, thin client

Server: Mid-range computerServer: Mid-range computer Dedicated to special function Dedicated to special function

such as such as database server, print database server, print server, web server, web server, server, application serverapplication server

Client and server share in processing taskClient and server share in processing taskExample, the World Wide WebExample, the World Wide Web

TelecommuncationsTelecommuncations

– Telecommunications: Telecommunications: the electronic the electronic transmission of signals for transmission of signals for communicationscommunications

– Telecommunications medium: Telecommunications medium: anything that carries an electronic anything that carries an electronic signal and interfaces between a sending signal and interfaces between a sending device and a receiving devicedevice and a receiving device

Telecommunications and Telecommunications and NetworksNetworks

Elements of a Telecommunications SystemElements of a Telecommunications System

Transmission MediaTransmission Media

Wired Transmission Media TypesWired Transmission Media Types

Wired Media TypesWired Media Types

Wireless Transmission Wireless Transmission Media TypesMedia Types

Radio WavesRadio Waves– BluetoothBluetooth

Short distances onlyShort distances only Relatively slow transmission speedRelatively slow transmission speed Developed for inter-device communicationsDeveloped for inter-device communications

– Wi-FiWi-Fi Standard supports up to 54MbpsStandard supports up to 54Mbps Supports longer distances than bluetoothSupports longer distances than bluetooth

InfraredInfrared– Signals sent as light wavesSignals sent as light waves– Short distanceShort distance– Unobstructed line of sightUnobstructed line of sight

MicrowaveMicrowave– High frequency radio signalHigh frequency radio signal– Capable of high-speed transmissionCapable of high-speed transmission– Unobstructed line of sightUnobstructed line of sight– Susceptible to interferenceSusceptible to interference

CellularCellular

NetworksNetworks

Computer network: Computer network: the the communications media, devices, and communications media, devices, and software needed to connect two or software needed to connect two or more computer systems or devicesmore computer systems or devices

Network nodes:Network nodes: the computers and the computers and devices on the networksdevices on the networks

Network TypesNetwork Types

Personal area network (PAN)Personal area network (PAN) Local area network (LAN)Local area network (LAN) Metropolitan area network (MAN)Metropolitan area network (MAN) Wide area network (WAN)Wide area network (WAN) International networkInternational network

Network TypesNetwork Types

A Typical LANA Typical LAN

Network TypesNetwork Types

A Wide Area NetworkA Wide Area Network

Is the interneta wide areanetwork?

Communications Software and Communications Software and ProtocolsProtocols

Communications software:Communications software: software software that provides a number of important that provides a number of important functions in a network, such as error functions in a network, such as error checking and data securitychecking and data security– Network operating system (NOS) Network operating system (NOS) – Network management softwareNetwork management software– Communications protocol:Communications protocol: a standard set of a standard set of

rules that controls a telecommunications rules that controls a telecommunications connectionconnection

Example, TCP/IP protocol that underlies the InternetExample, TCP/IP protocol that underlies the Internet

The InternetThe Internet

Internet: Internet: a collection of a collection of interconnected networks, all freely interconnected networks, all freely exchanging informationexchanging information

ARPANETARPANET– The ancestor of the InternetThe ancestor of the Internet– A project started by the U.S. Department A project started by the U.S. Department

of Defense (DoD) in 1969of Defense (DoD) in 1969

How the Internet WorksHow the Internet Works

Data is passed in chunks called packetsData is passed in chunks called packets– Internet Protocol (IP): Internet Protocol (IP):

communications standard that enables communications standard that enables traffic to be routed from one network to traffic to be routed from one network to another as neededanother as needed

– Transmission Control Protocol Transmission Control Protocol (TCP): (TCP): widely used transport-layer widely used transport-layer protocol that is used in combination with protocol that is used in combination with IP by most Internet applicationsIP by most Internet applications

How the Internet WorksHow the Internet Works

Routing Messages over the InternetRouting Messages over the Internet

Accessing the InternetAccessing the Internet

Several Ways to Access the InternetSeveral Ways to Access the Internet

Internet Service ProvidersInternet Service Providers

Internet service provider (ISP):Internet service provider (ISP): any company that provides any company that provides individuals or organizations with individuals or organizations with access to the Internetaccess to the Internet– Most charge a monthly feeMost charge a monthly fee– Many ISPs and online services offer Many ISPs and online services offer

broadband Internet access through broadband Internet access through digital subscriber lines (DSLs), cable, or digital subscriber lines (DSLs), cable, or satellite transmissionsatellite transmission

Applications that run over the Applications that run over the InternetInternet

World Wide WebWorld Wide Web Instant MessagingInstant Messaging EmailEmail File Transfer ProtocolFile Transfer Protocol TelnetTelnet All of these areAll of these are

– Software applicationsSoftware applications– Designed for the internetDesigned for the internet– All assume your computer understands TCP/IPAll assume your computer understands TCP/IP

The World Wide WebThe World Wide Web

Hypertext Transfer Protocol (HTTP): Hypertext Transfer Protocol (HTTP): Protocol that web servers and browsers Protocol that web servers and browsers use to send requests and informationuse to send requests and information

Hypertext Markup Language (HTML): Hypertext Markup Language (HTML): the standard page description language the standard page description language for Web pagesfor Web pages

Uniform Resource Locator (URL): Uniform Resource Locator (URL): an an assigned address on the Internet for each assigned address on the Internet for each computercomputer

Intranets and ExtranetsIntranets and Extranets

IntranetIntranet– Internal corporate network built using Internal corporate network built using

Internet and World Wide Web standards Internet and World Wide Web standards and productsand products

– Used by employees to gain access to Used by employees to gain access to corporate informationcorporate information

– Slashes the need for paperSlashes the need for paper

Intranets and ExtranetsIntranets and Extranets

ExtranetExtranet– A network based on Web technologies A network based on Web technologies

that links selected resources of a that links selected resources of a company’s intranet with its customers, company’s intranet with its customers, suppliers, or other business partnerssuppliers, or other business partners

Virtual private network (VPN): Virtual private network (VPN): a a secure connection between two points secure connection between two points across the Internetacross the Internet– Intranets and extranets often run over Intranets and extranets often run over

VPN’sVPN’s

Internet IssuesInternet Issues

PrivacyPrivacy– Spyware:Spyware: hidden files and information hidden files and information

trackers that install themselves secretly trackers that install themselves secretly when you visit some Internet siteswhen you visit some Internet sites

– Cookie:Cookie: a text file that an Internet a text file that an Internet company can place on the hard disk of a company can place on the hard disk of a computer systemcomputer system

Net IssuesNet Issues

SecuritySecurity– Cryptography:Cryptography: converting a message into a converting a message into a

secret code and changing the encoded message secret code and changing the encoded message back to regular textback to regular text

– Digital signature:Digital signature: encryption technique used encryption technique used to verify the identity of a message sender for to verify the identity of a message sender for processing online financial transactionsprocessing online financial transactions

– Firewall:Firewall: a device that sits between an internal a device that sits between an internal network and the Internet, limiting access into network and the Internet, limiting access into and out of a network based on access policiesand out of a network based on access policies

Net IssuesNet Issues