Week No. 5-Topic 6-Networks.pptx

Chapter 06: Computer Networks Stair, Reynolds and Chesney: Principles of Business Information Systems, Fourth edition (9781473774605) © Cengage Learning 2021 Principles • Effective communications are essential to organizational success • Communications technology lets more people send and receive...

Chapter 06: Computer Networks Stair, Reynolds and Chesney: Principles of Business Information Systems, Fourth edition (9781473774605) © Cengage Learning 2021 Principles • Effective communications are essential to organizational success • Communications technology lets more people send and receive all forms of information over great distances • The Internet is like many other technologies – it provides a wide range of services, some of which are effective and practical for use today, others are still evolving, and still others will fade away from lack of use • Because the Internet and the World Wide Web are becoming more universally used and accepted for business use, management, service and speed, privacy, and security issues must continually be addressed and resolved For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning Telecommunications • Telecommunication: The electronic transmission of signals for communications. • Telecommunications medium: Any material substance that carries an electronic signal to support communications between a sending and receiving device such as telephone, radio, and television. • Telecommunications impacts businesses greatly because it lessens the barriers of time and distance For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning A general model of telecommunications • A sending unit such as a person, a computer system, a terminal, or another device, sends the message signal to a telecommunications device. • The telecommunications device may process the signal, such as convert it into a different form or from one type to another. • The telecommunications device then sends the signal through a medium. • Another telecommunications device connected to the receiving computer (6) receives the signal. • The process can be reversed, and the receiving unit can send another message to the original sending unit. For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning A general model of telecommunications For use with PrinciplesFor of use Business Information Systems, with Principles of Business Information Systems, 3e 4e by Stair, & Reynolds & Chesney by Stair, Reynolds Chesney © 2018 Cengage Learning © 2021 Cengage Learning Synchronous & Asynchronous communication • Communication can occur synchronously or asynchronously: • With synchronous communication, the receiver gets the message almost instantaneously, when it is sent. • Examples are a phone call, and instant messaging services such as MSN • With asynchronous communication there is a measurable delay between the sending and receiving of the message, sometimes hours or even days. • Examples are sending a letter through the post office and e-mail • Both types of communications are important in business For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning Telecommunication Channels » Simplex channel : transmits data in only one direction. » Half-duplex channel: transmits data in either direction but not simultaneously. » Full-duplex: channel permits data transmission in both directions at the same time. » Channel bandwidth: refers to the rate at which data is exchanged, usually measured in bits per second (bps). For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning Telecommunication media types Guided transmission (using a solid medium) – – – – Twisted-pair wire Coaxial cable Fiber-optic cable Broadband over power lines For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning Telecommunication media types Wireless Transmission Media Types: Microwave Transmission Microwave is a high-frequency (300 MHz–300 GHz) signal sent through the air. For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning Telecommunication media types Satellite Transmission Communications satellites are relay stations that receive signals from one Earth station and rebroadcast them to another. For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning Transmission Media Types » 3G Wireless Communication – Wireless communication for mobile devices has evolved through four generations of technology and services. » 4G Wireless Communication – 4G broadband mobile wireless is delivering enhanced versions of multimedia, smooth video streaming, universal access, portability across all types of device and, eventually, worldwide roaming. » Wifi – Wi-fi is a medium-range wireless option typically operating up to about 30 metres around a single building. For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning Telecommunications Hardware » Modems: A device that converts (modulates and demodulates) communications signals so they can be transmitted over the communication media.  Modulation and Demodulation:Translating data from digital to analogue is called ‘modulation’, and translating data from analogue to digital is called ‘demodulation’. » Multiplexer: A multiplexer is a device that encodes data from two or more data sources onto a single communications channel, thus reducing the number of communications channel For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning How a Modem Works For use with PrinciplesFor of use Business Information Systems, with Principles of Business Information Systems, 3e 4e by Stair, & Reynolds & Chesney by Stair, Reynolds Chesney © 2018 Cengage Learning © 2021 Cengage Learning Multiplexer For use with PrinciplesFor of use Business Information Systems, with Principles of Business Information Systems, 3e 4e by Stair, & Reynolds & Chesney by Stair, Reynolds Chesney © 2018 Cengage Learning © 2021 Cengage Learning Telecommunications hardware » Private Branch Exchange:is a telephone switching exchange that serves a single organization. It enables users to share a certain number of outside lines (trunk lines) to make telephone calls to people outside the organization. » Bridge: A bridge connects one local area network (LAN) to another LAN that uses the same telecommunications protocol. For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning Telecommunications hardware » Switch: A device containing ports to which all the devices on the network can connect » Router: A telecommunications device that forwards data packets between computer networks » Gateway: A telecommunications device that serves as an entrance to another network For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning Networks and distributed processing • A computer network consists of communications media, devices, and software needed to connect two or more computer systems or devices • The computers and devices on the networks are called network nodes • Nodes can share data, information, and processing jobs • Organizations can use networks to share hardware, programs, and databases • Networks enable geographically separated workgroups to share information, • which fosters teamwork, innovative ideas, and new business strategies For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning Network types • Personal Area Network: • supports the interconnection of information technology close to one person • Local Area Network: • connects computer systems and devices within a small area (e.g., an office or a home) • Metropolitan Area Network: • connects users and their devices in an area that spans a campus or city • Wide Area Network: • connects large geographic regions • International networks: • Networks that link systems between countries are called international networks. For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning Network types For use with PrinciplesFor of use Business Information Systems, with Principles of Business Information Systems, 3e 4e by Stair, & Reynolds & Chesney by Stair, Reynolds Chesney © 2018 Cengage Learning © 2021 Cengage Learning WAN For use with PrinciplesFor of use Business Information Systems, with Principles of Business Information Systems, 3e 4e by Stair, & Reynolds & Chesney by Stair, Reynolds Chesney © 2018 Cengage Learning © 2021 Cengage Learning Client/Server systems • In client/server architecture computers called servers are dedicated to special functions • Each server is accessible by all computers on the network • Servers can be computers of all sizes • A client is any computer (often a user’s personal computer) that sends messages requesting services from the servers on the network For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning The Internet • The Internet is the world’s largest computer network • Actually, it is a collection of interconnected networks, all freely exchanging information. For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning The Web • The World Wide Web was developed as an internal document-management system. • The World Wide Web (web, WWW, or W3) has grown to a collection of tens of thousands of independently owned computers that work together as one in an Internet service. • A Web browser is used to access and read Web pages which are usually written in HyperText Markup Language (HTML) For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning Web 2.0 » Web 2.0, also called as Social Web, refers to World Wide Web websites that emphasize usergenerated content, usability, participatory culture and interoperability (this means that a website can work well with other products, systems, and devices) Ref: Reference Book No. 1, Chapter 5 – Joseph Valacich , Christoph Schneider, "Information Systems Today: Managing in a Digital World" 7th Edition, 2015 ISBN-13: 978-0133940473 ISBN-10: 01339404705 For use with PrinciplesFor of use Business Information Systems, with Principles of Business Information Systems, 3e 4e by Stair, & Reynolds & Chesney by Stair, Reynolds Chesney © 2018 Cengage Learning © 2021 Cengage Learning Web 2.0 Technologies Wikis: a website or database developed collaboratively by a community of users, allowing any user to add and edit content. Tags: It provide a useful way to group related posts together and to quickly tell readers what a post is about. Blogs: A blog is a discussion or informational website published on the World Wide Web. Netcast: A broadcast transmitted over the Internet. Self Publishing: It is the publication of media by its author without the involvement of an established publisher. For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning Web 2.0 Technologies Social Networking: the use of dedicated websites and applications to interact with other users, or to find people with similar interests to one's own. Viral Marketing: a method of marketing whereby consumers are encouraged to share information about a company's goods or services via the Internet. Crowdsourcing: obtain (information or input into a particular task or project) by getting the services of a large number of people, either paid or unpaid, typically via the Internet. Ref: Reference Book No. 1, Chapter 5 Joseph Valacich , Christoph Schneider, "Information Systems Today: Managing in a Digital World" 7th Edition, 2015 ISBN-13: 978-0133940473 ISBN-10: 01339404705 For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning Intranet and Extranet • Intranet: an intranet is an internal company network built using Internet and World Wide Web standards and products. • Extranet: When selected externals (such as supplies, customers, business partners) are given access to the intranet, it becomes an extranet. For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning Summary • Telecommunications: the electronic transmission of signals for communications, by such means as telephone, radio, and television • Guided transmission media types: twistedpair wire, coaxial cable, fiber-optic cable, and broadband over power lines • Wireless transmission types: microwave, radio, and infrared For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning Summary (cont.) • Network types: personal area network (PAN), local area network (LAN), metropolitan area network (MAN), wide area network (WAN), international networks, and mesh networking • Client/server systems: multiple computer platforms dedicated to special functions such as database management, printing, communications, and program execution For use with Principles of Business Information Systems, 4e by Stair, Reynolds & Chesney © 2021 Cengage Learning