Class Notes Updated 07 Sep 07

MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected]) Using specific examples, describe how computerization would help your department perform more efficiently and effectively. Also explain how computerization will help better decision-making, analysis and planning?

Q1

Q2

In what ways will the use of IT and Internet enhance your job function as a Middle Manager? Discuss with examples with respect to either HRD Function or Marketing Function or Finance Function?

Q3

Giving suitable examples explain how and why IT and computers have contributed in increasing productivity and competitiveness of organizations in doing business.

Q4

Write a note on how IT can help an organization in gaining competitive advantage

Q87

How does IT contribute towards increasing productivity and in doing business better? Explain with reference to any one function in your organization in detail.

(Ans 1-4, 87) Scenario before IT • • • • •

More paper work Lack of storage space Communication was expensive and huge Telephone bills were incurred Redundancy of information Lack of Information security

Scenario after IT • • • • • • • •

Less paper work due to the use of computerized transactions Storage space greatly increased to store huge amounts of data running into terabytes Streamlined communication and convergence has enabled different modes of communication as well as different devices to communicate and share information across the globe Communication today is less expensive and in most cases almost free as many calls happen online using free softwares like skype and other online chat and messenger applications. Use of databases have helped optimize data and reduce redundancy thereby offering easy and powerful access to the information warehouses and showing different users the data they seek in different ways wherever and whenever they need it. Use of sophisticated databases has also brought in data security leading to overall information security and safety. This allows for only authorized users to communicate and access data from the databases Data Analysis and generation of Metrics have helped users and organizations perform their decision making activities to be more effective and accurate. Information has now become more Accessible, Reachable, Portable and Editable across mediums and devices and across users as well.

IT and Internet has enhanced the job functions of a middle managers working in the HR, Finance and Marketing functions in the following manner: HRD Function •

Recruitment processes have been automated wherein software tools like CV scanners and ATS (Applicant Tracking Systems) have been introduced to scan and filter the

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

• • •

• • • •

appropriate CV’s from thousand applicants and then tracking the applicants candidature from recruitment to selection in the organization. Payroll function also uses IT to automate disbursement of salaries and claims and other financial related transactions that concern the employees or the organization and its stakeholders Online banking ensures that organizations can deposit employee salaries in banks and employees can transact online without having to physically visit a bank or deal in physical cash. Use of E-HRIS (Electronic Human Resource Information Systems) has automated the tasks of employee – HR communication. They serve as a virtual HR manager who takes care of employee related transactions online. These transactions can range from entering daily times sheets, claiming for late sitting re-imbursements, Mediclaims and LTA claims, posting grievances online to applying for leave online etc. Allocations of employees and online skill matrices of employees with their skill sets helps the HR functions to optimally use the human capital Use of Intranets have empowered the HR managers to leverage this platform for Internal communication within the organization Today Employee Satisfaction and other key surveys are conducted online using the companies Intranets and the data collected is collated, analysed and used for decision making by the HR function. Use of Enterprise HR applications like SAP, Oracle PeopleSoft etc have enabled the HR functions to work well with the human capital across business functions, branches and continents in a very synchronous and effective manner

Finance Function • • • • • •

Use of software’s like Tally and other financial accounting packages have helped the finance departments and financial accountants greatly by automating financial transactions and ensuring their accuracy and integrity Today balance sheets and other financial records can be easily created, maintained and distributed online to stakeholders Online banking has enabled transactions between financial departments and banks Usage of financial modules of Enterprise Resource Planning applications have empowered organizations to effectively manage their finances Automated tools help Finance managers make projections and predictions thereby guiding the overall organization goals E-Finance has reduced paperwork and created a revolution where digital money / transactions have greatly impacted global electronic commerce and global transactions

Marketing Function • • • • •

Today Marketing managers use tools like e-Marketing to reach out to customers across the globe Marketing has leveraged the power of IT and internet in bringing together new markets and new customers and has created a virtual marketplace where users, organizations exchange goods, services, information, ideas etc. Customers can now give their product related suggestions, feedbacks and even register their issues or complaints to the manufacturing or product development departments directly using CRM (Customer Relationship Mgmt) softwares Middle to high level managers can use the internet and the various communication facilities that come with it to network with their userbase Online banner advertisements can rake in a lot of money and generate new revenue streams

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

• • •

•

Traditional brick and mortar business is now being complimented and eventually replaced by online business and e-Commerce Enterprise Resource Planning Applications like SAP, Oracle etc have modules for Marketing and Distribution that helps the materials planning function, logistics, Supply Chain functions and CRM functions as well. Marketing managers can now IT enable the small and third party vendors to connect to their organizations network so that they can check the organizations inventory levels and continuously replenish them as and when required, this helps them to save a lot as they do not have to store goods unnecessarily thereby incurring warehousing expenses. Instead they can operate on Just in Time basis. Marketing Services in the services industry can also be greatly enhanced by use of IT and internet as now all services can be accessed online, and users can get help online as well as offline.

This is how computerization, the advent of IT and Internet has helped departments like these to perform more efficiently and enhanced the role of middle level managers in organizations. (Ans 5-8)

An operating system (OS) is a set of computer programs that manage the hardware and software resources of a computer. It is a system software that manages the operations of a computer. Without it you cannot start a computer. The most important program that runs on a computer. Every general-purpose computer must have an operating system to run other programs. Operating systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers. For large systems, the operating system has even greater responsibilities and powers. It is like a traffic cop -- it makes sure that different programs and users running at the same time do not interfere with each other. The operating system is also responsible for security, ensuring that unauthorized users do not access the system.

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

Most operating systems come with an application that provides an interface to the OS managed resources. These applications have had command line interpreters (eg. DOS – Disk Operating System) as a basic user interface but, since the mid-1980s, have been implemented as a graphical user interface (GUI) for ease of operation. Operating Systems themselves have no user interfaces; the user of an OS is an application, not a person. The operating system forms a platform for other system software and for application software. Windows, Linux, and Mac OS are some of the most popular OSes. Types of Operating Systems a) Single User Operating System b) Multi-User Operating System Single User Operating System • • •

This OS is used for standalone PC’s (eg. MS DOS) OS/2 and Win NT ar also single user, multi tasking OS for micro computers Most Personal Computers and Workstations are Single User computer systems that have a single user OS

Multi-User Operating System • •

This OS is used for those computers having many terminals connected to it. Eg. Linux, Netware, Unix All Mainframes and Minicomputers are multi-user systems that run on a multi-user OS

Operating System Techniques •

Multiprogramming - In which a single CPU works on two or more programs - In this technique the OS keeps the CPU busy by allowing either batch multiprogramming or timesharing multiprogramming

•

Multiprocessing - Refers to a computers ability to support more than one process (program) at the same time. - It is also referred to as parallel processing - Unix is one of the most widely used multiprocessing systems

•

Multitasking - It is the computers ability to execute more than one task at the same time. - In multitasking only one CPU is involved, but it switches from one program to another so quickly that it gives the appearance of executing all of the programs at the same time.

•

Multithreading - It’s the ability of an OS to execute different parts of a program, called threads, simultaneously. - Programmers must carefully design the programs in such a way that all the threads can run at the same time without interfering with each other.

•

Real Time - It means occurring immediately.

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

-

Real time operating systems are systems that respond to input immediately. They are useful for tasks like GPS, Navigation in which computers are required to react to a steady flow of new information without interruption or delays.

Functions of an Operating System a) Process Management - OS helps the CPU allocate resources for executing programs / processes. A process is a program in execution. E.g. Spooling, printing etc. The OS helps in the creation, deletion, suspension, resumption and synchronization of processes. b) Memory Management - Memory is a large array of words and bytes each with its own address. The CPU reads from and writes to memory. The OS keeps track of currently used memory and who is using it. It decides which processes to load in memory when memory space becomes available and it allocates & de-allocates memory space as needed. c) Storage Management - The OS deals with the allocation and reclamation of storage space when a process / program is opened or terminated. The OS helps in reading of data from the disk to the main memory (RAM) in order to execute processes. d) I/O (Input / Output) System - The OS helps the I/O devices to communicate easily as it hides the peculiarities and device driver details from the end user. e) File Management - The OS provides a logical view of Information Storage, it maps files on physical devices. It helps in the creation, deletion of files and directories, manipulating of files and directories on to the storage and also does a backup. It offers a very user friendly interface like the windows explorer for end users like us to work with files easily. f)

Protection System - The OS protects processes from interference of other processes and it checks for authorization of processes and allows them to access CPU resources.

g) Networking - Distributed computing systems require Multi-user OS for allowing processes and users the access to shared resources on the network. h) System and Resource Monitoring - The OS helps monitor resource usage and provides information on system performance.

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

(Ans 10-11) GUI (Graphical User Interface) Abbreviated GUI (pronounced GOO-ee). A program interface that takes advantage of the computer's graphics capabilities to make the program easier to use. Well-designed graphical user interfaces can free the user from learning complex command languages. Graphical user interfaces, such as Microsoft Windows and the one used by the Apple Macintosh, feature the following basic components:

  

  

pointer: A symbol that appears on the display screen and that you move to select objects and commands. Usually, the pointer appears as a small angled arrow. Text -processing applications, however, use an I-beam pointer that is shaped like a capital I. pointing device: A device, such as a mouse or trackball, that enables you to select objects on the display screen. icons: Small pictures that represent commands, files, or windows. By moving the pointer to the icon and pressing a mouse button, you can execute a command or convert the icon into a window. You can also move the icons around the display screen as if they were real objects on your desk. desktop: The area on the display screen where icons are grouped is often referred to as the desktop because the icons are intended to represent real objects on a real desktop. windows: You can divide the screen into different areas. In each window, you can run a different program or display a different file. You can move windows around the display screen, and change their shape and size at will. menus: Most graphical user interfaces let you execute commands by selecting a choice from a menu.

The first graphical user interface was designed by Xerox Corporation's Palo Alto Research Center in the 1970s, but it was not until the 1980s and the emergence of the Apple Macintosh that graphical user interfaces became popular. One reason for their slow acceptance was the fact that they require considerable CPU power and a high-quality monitor, which until recently were prohibitively expensive. In addition to their visual components, graphical user interfaces also make it easier to move data from one application to another. A true GUI includes standard formats for representing text and graphics. Because the formats are well-defined, different programs that run under a common GUI can share data. This makes it possible, for example, to copy a graph created by a spreadsheet program into a document created by a word processor. Many DOS programs include some features of GUIs, such as menus, but are not graphics based. Such interfaces are sometimes called graphical character-based user interfaces to distinguish them from true GUIs. CUI (Character User Interface) Describes programs capable of displaying only ASCII (American Standard Code for Information Interchange) characters. Character-based programs treat a display screen as an array of boxes, each of which can hold one character. When in text mode, for example, PC screens are typically divided into 25 rows and 80 columns. In contrast, graphics-based programs treat the display screen as an array of millions of pixels. Characters and other objects are formed by illuminating patterns of pixels.

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

Because the IBM extended ASCII character set includes shapes for drawing pictures, characterbased programs are capable of simulating some graphics objects. For example, character-based programs can display windows and menus, bar charts, and other shapes that consist primarily of straight lines. However, they cannot represent more complicated objects that contain curves. A Command Line Interface or CLI is a method of interacting with an operating system or software using a command line interpreter. A command line interpreter is a computer program that reads lines of text entered by a user and interprets them in the context of a given operating system or programming language. This requires the user to know the names of the commands and their parameters, and the syntax of the language that is interpreted. From the 1960s onwards, user interaction with computers was primarily by means of command line interfaces Distinguish between GUI & CUI / CLI Graphical User Interface (GUI) • Generally used in Multimedia, elearning, Demo’s etc • Consists of a Visual / Graphical control featuress using toolbars, buttons, icons, menus etc • Used to create animations or pictures • • • •

Character User Interface (CUI) • Generally used in programing languages • Consists of character control features such as text elements or characters

A variety of input devices are used to manipulate text & images as visually displayed Its usually a graphical Interface, eg. Web pages, Navigation etc GUI can be affected by Virus Eg. Windows OS, Apple OS

• • • • •

Used to create words or sentences or syntax commands Allows users to specify options through function keys Its purely textual (commands which are understood by computers) Proves less afftected by virus Eg. Disk Operating System (DOS)

All Operating Systems today provide a Graphical User Interface. Applications use GUI, eg. Web Applications, ATM Softwares etc. The GUI uses metaphors for helping users understand the nature of activities they can perform. Eg. Home Icon which indicates the homepage, Lock and Key Icon which indicates security etc. GUI may also include audio, video. GUI is also known as “Look and Feel”. Apple Mac OS & Win OS are todays familiar GUI’s.

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

(Ans 12, 16) The Birth of the Internet While computers were not a new concept in the 1950’s there were relatively few computers in existence and the field of computer science was still in its infancy. Most of the advances in technology at the time – cryptography, radar, battlefield communications – were due to military operations during World War II, and it was in fact, government activities that led to the development of the Internet. On October 4, 1957, the Soviets launched Sputnik, the first unmanned satellite in space, and the US Government under President Eisenhower subsequently launched an aggressive military campaign to compete and surpass the Soviet activities. From the launch of Sputnik and the U.S.S.R. testing its first ICBM (Intercontinental Ballistic Missle) the Advanced Research Projects Agency (ARPA) was born. ARPA was the U.S. Governments research agency for all space and strategic missile research. In 1958, NASA was formed, and the activities of ARPA moved away from aeronautics and focused mainly on computer science and information processing. One of ARPA’s goals was to connect mainframe computers at different universities around the country so that they would be able to communicate using a common language and a common protocol. Thus the ARPAnet – The world’s first multiple-site computer network—was created in 1969. The original ARPAnet eventually grew into the Internet. The Internet was based on the concept that there would be multiple independent networks that began with the ARPAnet as the pioneering packet-switching network but would soon include packet satellite networks and ground-based radio networks. Why the Intranet is also known as the network of networks The intranet is the publicly accessible worldwide system of interconnected computer networks that transmit data by packet switching using a standardized Internet Protocol like TCP/IP (i.e. Transmission Control Protocol / Internet Protocol) and may other protocols. It is made up of thousands of smaller commercial, academic, domestic and government networks. It carries various information and services, such as electronic mail, online chat and the interlinked web pages and other documents of the World Wide Web. Unlike online services, which are centrally controlled, the Intranet is decentralized by design. Each Internet Computer, called a host, is independent. Its operators can choose which Internet services to use and which local services to make available to the global internet community. It is possible to gain access to the Internet through a commercial ISP (Internet Service Provider).

Illustration of the Internet Architecture:

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

Difference between Internet and the World Wide Web Many people use the terms Internet and World Wide Web interchangeably, but in fact the two terms are not the same thing. They are both separate but related concepts. The Internet is a massive network of networks. It connects millions of computers together globally, forming a network in which any computer can communicate with any other computer as long as they are both connected to the Internet. Information that travels over the Internet does so via a variety of languages known as protocols. The World Wide Web also known as the “Web” is a way of accessing information over the medium of the Internet. It is an information-sharing model that is built on top of the Internet. The web uses the HTTP Protocol. Web services which use HTTP to allow applications to communicate in order to exchange business logic, use the Weorld Wide Web to share information. The web also makes use of browsers such as Internet Explorer or Netscape, or Firefox to access web documents called web pages that are linked to each other via hyperlinks. Web documents contain graphics, sounds, texct and video. So the Web is just a lage portion of the Internet but the two terms are not the same and should not be confused with each other.

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

(Ans 13, 29) Internet has paved the way for Electronic Commerce (e-Commerce), which can be defined as the ‘business activities conducted using electronic data transmission technologies, such as those used on the Internet and the World Wide Web.’ It involves buying, selling, transferring or exchanging products, services, and / or information via computer networks and is a major distribution channel for goods, services and managerial and professional jobs. Companies today are interested in E-Commerce simply because it can help increase sales and profits and decrease costs. Even a small firm that advertises on the web can get their message out to potential customers in every country in the world. E-Commerce has proven to have many benefits and advantages. E-Commerce plays a major role in global reach. It expands the marketplace to national and international markets. E-Commerce allows firms to now reach narrow market segments that are geographically scattered. People in third world countries are now able to enjoy products and services that were unavailable in the past. It is important to understand that not only does E-Commerce benefit the Seller or the Company, but it also benefits the buyer or the customer. One main benefit of E-Commerce is that it is particularly useful in creating virtual communities that become ideal target markets for specific types of products and services. Just as E-Commerce increases the sales opportunities for the seller, it increases the purchasing opportunities for the buyer. With minimum investment, a business can use E-Commerce to easily and quickly identify the best suppliers, more customers and the most suitable business partners worldwide. By expanding the base of consumers and suppliers, enables an organization to buy at cheap rates and sell more at competitive and lower prices. E-Commerce has also given a great boost to Supply Chain Management (SCM). Today using ECommerce companies can manage the integration of all activities within and between enterprises. Some of these activities include Procurement, Inventory Management and Logistics. The Internet and E-Commerce revolution allows you to manage your Supply Chain better by effectively integrating a system of suppliers, partners, customers and employees. This nowadays is done online with the help of customized Extranets, use of Virtual Private Networks, Emails and other collaboration tools and hence today this activity can be referred to as e-SCM. The Internet and E-Commerce has benefited the SCM process by decreasing operating costs through reduced inventory requirements. It has improved customer satisfaction by maintaining adequate inventory and has improved productivity and logistics. The Internet will help you provide better customer service by delivering rich on-demand solutions. Better customer service results in brand loyalty and this results in good revenue. Internet and ECommerce has helped companies support their existing customers, develop new customers and retain profitable customers. Today customers can reach the manufacturers online and share market research data; they can make complaints online and even send their suggestions for product / service improvements online, and even track he progress of their orders online (e.g. Fedex allows its customers to track the status of their courier packages online.) Thus it can be said that the use of Internet and E-Commerce has improved margins, increased customer awareness and increased competitive advantage in today’s new economy and has brought the manufacturers and customers closer to each other and has resulted into better CRM and SCM.

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected]) Q25

Computers & communications seem to merge together seamlessly. Discuss?

Q26

Why are the computer and computer related devices networked in an organization?

Q27

What are the benefits of networking?

Q28

An integrated company wide computerization is the only way of deriving full benefits of Information technology today. Discuss?

Q35

What is networking?

Q36

Describe the benefits of networking with examples?

Q37

Why are computers and computer related devices networked in an organization?

(Ans 25, 26, 27, 28, 35, 36, 37) Definition of Networking Networking can be explained as the linking of a number of devices, such as computers, workstations, printers, and Audio Video gear into a network (system) for the purpose of sharing resources and exchange of information between them. A network is not just a bunch of computers with wires running between them. When properly implemented, a network is a system that provides its users with unique capabilities, above and beyond what the individual machines and their software applications can provide. Most of the benefits of networking can be divided into two generic categories: connectivity and sharing. Networks allow computers, and hence their users, to be connected together. They also allow for the easy sharing of information and resources, and cooperation between the devices in other ways. Since modern business depends so much on the intelligent flow and management of information, this tells you a lot about why networking is so valuable. Here are some of the specific advantages generally associated with networking: a) Connectivity and Communication: Networks connect computers ad the users of those computers. Indivduals within a building or work group can be connected into local area networks (LANs); LANs in distant locations can be interconnected into larger wide area network (WANs). Once connected, it is possible for network users to communicate with each other using technologies such as electronic mail. This makes the transmission of business (or non-business) information easier, more efficient and less expensive than it would be without the network. Today people and processes have come together via the emergence of networks. b) Data Sharing: One of the most important uses of networking is to allow the sharing of data. Before networking was common, an accounting employee who wanted to prepare a report for her manager would have to produce it on his PC, put it on a floppy disk and then walk it over to the manager, who would transfer the data to his or her PC’s hard disk. Today true networking allows thousands of employees to share data much more easily and quickly than this. More so, it makes possible applications that rely on the ability of many people to access and share the same data, such as databases, group software development, and much more. Intranets and extranets can be used to distribute corporate information between sites and to business partners.

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

c) Hardware Sharing: Networks facilitate the sharing of hardware devices. For example, instead of giving each of 10 employees in a department an expensive color printer, one printer can be placed on the network for everyone to share. d) Internet Access: The internet is itself an enormous network, so whenever you access the Internet, you are using a network. The significance of the Internet on modern society is hard to exaggerate, especially for those of us in technical fields. e) Internet Access Sharing: Small computer networks allow multiple users to share a single Internet connection. Special hardware devices allow the bandwidth of the connection to be easily allocated to various individuals as they need it, and permit an organization to purchase one high-speed connection instead of many slower ones. f) Data Security, Data Backup and Management: In a business environment, a network allows the administrators to much better manage the company’s critical data. Instead of having this data spread over dozens or even hundreds of small computers in a haphazard fashion as their users create it. Data can be centralized on shared servers. They can also be easily backed up. This makes it easy for everyone to find the data, makes it possible for the administrators to ensure that the data is regularly backed up, and also allows for the implementation of security measures to control who can read or change various pieces of critical information. g) Performance Enhancement and Balancing: Under some circumstances, a network can be used to enhance the overall performance of some applications by distributing the computation tasks to various computers on the network. h) Entertainment: Networks facilitate many types of games and entertainment. The Internet itself offers many sources of entertainment. Today many multi-player games exist that operate over a local area network. Many home networks are set up for this reason, and gaming across wide area networks (including the internet) has also become quite popular.

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

The ISO – OSI Model for Networking

(Ans) The Open Systems Interface means a system that can communicate with any other system that follows the specified standards, formats and semantics. The Open system Interface works well because of protocols that specify how the communicating parties may communicate. The OSI Model supports two types of ‘Protocols’ namely:

a) Connection – Oriented: - Sender and receiver first establish a connection, possibly negotiate on a protocol - Transmit the stream of data - Release the connection when done - Eg. Telephone connection

b) Connectionless: - No advance setup is needed - You can transmit the messages to the receiver irrespective of whether the receiver is online or offline.

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

Features of the OSI Model are listed below: • • • • • •

Consists of 7 layers. Each layer deals with a specific aspect of communication Each layer provides an interface to the layer above it. In other words each layer above provides some support to the layer before it. Messages are sent from the top layer (i.e. Application Layer) and is passed on the next lower layer until the message reaches the bottom layer (i.e. Physical Layer). At each level / layer, a header may be added to the message. Some layers add both a header and a trailer. The lowest layer transmits the message over the network to the receiving machine. The physical layer of the sender communicates with the physical layer of the receivers machine Each layer then strips the header or trailer, handles the message using the protocol provided by the layer and passes it on the next layer above it, until it moves right up to the application layer of the receiver’s machine.

a) The Physical Layer: Following are the characteristics of the Physical Layer: • • •

The phsyical layer is concerned with the transmission of bits It follows a two way or one way transmission It follows standard protocols which deal with electrical, mechanical and signalling interfaces

b) The Data Link Layer: Following are the characteristics of the Data Link Layer: • • • •

•

Handles errors in the phyical layer Groups bits into frames and ensures their correct delivery Adds some bits at the beginning and end of each frame plus the checksum The Data Link Layer on the receivers machine verifies the checksum and if the checksum is not correct, it asks for retransmission Consists of two layers (Logical Link Control) which defines how data is transferred over the cable and provides data link service to the higher layers. The second layer is (Medium Access Control or MAC layer) which defines who can use the network when multiple computers are trying to access the network simultaneously.

c) The Network Layer: Following are the characteristics of the Network Layer: • • • •

Concerned with the transmission of packets Chooses the best path to send a packet (routing) to ensure speedy delivery of data It may be complex in a large network (e.g. Internet) It uses a connection oriented protocol called X.25 for telephone connections and also used Internet Protocol for establishing connectionless networks.

d) The Transport Layer: Following are the characteristics of the Transport Layer:

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

• • •

Since the network layer does not deal with lost messages, the transport layer above it ensures reliable service This layer breaks the message from the sessions layer above it into small packets, assigns sequence number and sends them to the network layer below it for transmission over the network This layer is also supported in the Internet Protocol suite.

e) The Sessions Layer: Following are the characteristics of the Sessions Layer: • • •

Very few applications use this. Its an enhanced version of the transport layer and helps in dialog control, synchronization faciltiies. Not supported by the Internet Protocol suite

f) The Presentation Layer: Following are the characteristics of the Presentation Layer: • • •

Very few applications use it Concerned with the semantics of the bits sent Sender can tell the receiver the format of the data that is being sent

g) The Application Layer: Following are the characteristics of the Application Layer: • • •

This is the layer where users actuall work on This layer consists of applications which communicate using protocols Email, file transfer, remote login applications use protocols like SMTP, FTP, Telnet etc.

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

Understanding the Network Tree

(Ans) The following illustration outlines the concepts that belong to the world of networking and explains their hierarchy.

Network Tree

Medium

Wired

Geographical Distance / Location

Wireles s

Co-Axial Cable

Infrared

Twisted Pair Cable

Blue Tooth

Fiber Optic Cable

Wi-Fi

Topology

LAN

Bus

MAN

Ring

WAN

Star

SAN

Mesh

Switching

Circuit

Packet

Wi-Max

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

Networks > Medium: Wired > Coaxial

Cable

A type of wire that consists of a center wire surrounded by insulation and then a grounded shield of braided wire. The shield minimizes electrical and radio frequency interference. Coaxial cabling is the primary type of cabling used by the cable television industry and is also widely used for computer networks, such as Ethernet. Although more expensive than standard telephone wire, it is much less susceptible to interference and can carry much more data.

Features: • • • • •

Used extensively in LANs. Has a single central conductor surrounded by a circular insulation layer and a conductive shield. Offers a high bandwidth of upto 400 Mhz. Offers a high quality of data transmission Offers maximum data transfer rates of 100 Mbps

Problems: •

It can have signal loss when data is sent at high frequencies

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

Networks > Medium: Wired > Twisted

Pair Cable

Features: • • • • • •

Extensively used in telephone circuits where several wires are insulated and put together Offers bandwidth of around 250 Khz It has a low signal to noise ratio (crosstalk) It offers a low data transfer rate Its preferred for short distance communications Its generally used in LAN

Networks > Medium: Wired > Fiber

Optic Cable

Features: • • • •

Used for applications requiring a high quality and high bandwidth of data transfer Uses light instead of electric pulses for data transmission It offers very high frequency ranges of around 20,000 Mhz and higher A single fiber can support over 30,000 telephone lines

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

• • • •

It offers data transmission rates of 400 Mbps and higher It has become very popular for LAN and MAN as well as for Intercontinental links It has a high signal to noise ratio and is very difficult to tap into the data transmission happening inside an optic fiber Earlier its cost was a big drawback but today the use of pure plastic has made optic fiber very economical and commercially feasible to use.

Networks > Medium: Wireless > Infrared Infrared technology has been around for ages, and is something that we’ve all come to take for granted in television, VCR, DVD remote control devices. What Infrared does? Infrared allows transmission of data over very short distances. One cannot transmit huge amounts of data via Infrared. For example, the remote control unit and the equipment share a special radio frequency or code, which allows the remote unit to transmit a one-way signal. Just point the remote device at whatever you want to control, and press the button. How it works? IR technology only works over short distances of less than 25 feet, and there cant be anything solid, like walls, standing in the way as an obstacle. Infrared is a one-way communication. It requires a clear line of sight between the devices. How it is used? Most of today’s computers and printers have built-in infrared technology that allows you to print without bulky cables. All mobile phones have infrared built in as well for allowing their users to do a data transfer with other devices like beaming addresses, notes and other data.

Networks > Medium: Wireless > Bluetooth Bluetooth wireless technology is a short-range radio technology. Bluetooth wireless technology makes it possible to transmit signals over short distances between telephones, computers and other devices and thereby simplify communication and synchronization between devices. Bluetooth is the name of a protocol for a short range (10 meter) frequency-hopping 2.4 GHz radio link between wireless devices such as a mobile phone and a PC. The idea is to make connections between different electronic items much easier and simpler, and without a lot of operator intervention. Bluetooth was launched in 1998 as a joint effort between Ericsson, IBM, Intel, Nokia and Toshiba. Over 1000 companies are now involved in the effort -- so you can see that it has stirred a lot of interest in the wireless community. Bluetooth is similar to infrared, but taken a step further. Instead of one-way transmissions, Bluetooth allows multiple devices from multiple manufacturers to speak the same wireless language without the conflicts that are found in standard infrared. The Bluetooth standard was jointly developed by a group of key players in the technology industry to ensure compatibility between various wireless devices. It was named after the dutch king Harold Bluetooth who was famous for bringing together the warring tribes of the Scandinavian region and built a strong network of allies.

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

What Bluetooth does? Bluetooth operates over short distances of around 30 feet or less, and it requires a clear line of sight between the devices. Bluetooth allows you to create your own PWAN (private wireless area network) where you can hook up upto eight devices without the hassle of cables and cords. Popular day to day use of Bluetooth can be found in many of today’s wireless keyboards, wireless mouse, cellphone handsets etc. How Bluetooth works? Bluetooth operates over the unlicensed 2.5 Ghz radio spectrum which allows Bluetooth-enabled equipment to operate anywhere in the world. Bluetooth uses more than 71 different frequencies, which allows a signal to hop around from one frequency to another to avoid conflicts with other devices. How is Bluetooth used? Bluetooth enabled PDAs such as Pocket PC, can synchronize email, documents and contact information with a bluetooth enabled PC without the need of cradles, cables or plugs. Bluetooth enabled mobile phones can communicate with other bluetooth enabled devices thereby allowing data transfer. Bluetooth enabled wireless headsets can be used with a mobile phone to provide hands free usage without the hassle of cords and plugs. Like Infrared, its limitation is that it is a short range mode of communication.

Networks > Medium: Wireless > Wi-Fi Wireless Ethernet or Wi-Fi is the latest standard for long-range wireless networking. It goes further and faster than Infrared or Bluetooth and does not require a clear line of sight. Wireless local area networks (WLANs) are a lot less expensive and much easier to set up than traditional wired networks. Because they are easy and inexpensive, wireless networks have become very popular for home and small business networks and have found a niche in hospitals and clinics where its important to securely connect people to shared file servers, printers, Internet connections and other resources. What does Wi-Fi do? Wi-Fi is based on the IEEE (Institute of Electronic and Electrical Engineers) 802.11 specifications. There are currently four deployed 802.11 variations, namely: 802.11(a), 802.11(b), 802.11(g) and 802.11(n). The (b) standard allows upto 11Mbps while both (a) and (g) allows upto 54 Mbps. The new (n) specification will allow even higher speeds of upto 100 Mbps and beyond. The 802.11(a) standard works in the 5GHz frequency band, and the others work in the 2.4GHz band. How does Wi-Fi work? Wi-Fi technology operates using the unlicensed radio frequencies in the 2.4GHz to 5GHz range. 2.4GHz for both the 802.11(b) and 802.11(g) and the 5GHz range for 802..11(a). The primary difference between the Wi-Fi signals and Infrared or Bluetooth is that Wi-Fi does not require the devices to have a direct line of sight. Wi-Fi tranmits data over radio signals that are sent/received via little antennas that are connected to the devices.

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

How is Wi-Fi used? Wi-Fi technology is used to create a fast, wireless, low cost network. Notebook PCs, Laptops, Tablet PCs, desktops, handheld devices etc can now talk to each other as well as the internet using Wi-Fi. Wi-Fi networks are springing up in airports, hotels, convention centers, hospitals and health care centers. Even airplanes like Ethihad Airways has Wi-Fi access inside their airplanes.

Networks > Medium: Wireless > Wi-Max

The two driving forces of modern Internet are broadband and wireless. The WiMax standard combines the two, delivering high-speed broadband Internet access over a wireless connection. WiMax is the next generation of WiFi, or wireless networking technology that will connect you to the Internet at faster speeds and from much longer ranges than current wireless technology allows. WiMAX (Worldwide Interoperability for Microwave Access) is the IEEE 802.16 standards-based wireless technology that provides MAN (Metropolitan Area Network) broadband connectivity. WiMax is based on the IEEE 802.16 Air Interface Standard (AIS). WiMax delivers a point-tomultipoint architecture, making it an ideal method for carriers to deliver broadband to locations where wired connections would be difficult or too costly. It may also provide a useful solution for delivering broadband to rural areas where high-speed lines have not yet become available. A WiMax connection can also be bridged or routed to a standard wired or wireless Local Area Network (LAN).

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

The so-called “last mile” of broadband is the most expensive and most difficult for broadband providers, and WiMax provides an easy solution. Although it is a wireless technology, unlike some other wireless technologies, it doesn’t require a direct line of sight between the source and endpoint, and it has a service range of 30 miles. It provides a shared data rate of up to 70 Mbps, which is enough to service up to a thousand homes with high-speed access. WiMax offers some advantages over WiFi, a similar wireless technology, in that it offers a greater range is more bandwidth efficient. Ultimately, WiMax may be used to provide connectivity to entire cities, and may be incorporated into laptops to give users an added measure of mobility. WiMax requires a tower, similar to a cell phone tower, which is connected to the Internet using a standard wired high-speed connection, such as a T3 line. But as opposed to a traditional Internet Service Provider (ISP), which divides that bandwidth among customers via wire, it uses a microwave link to establish a connection. Because WiMax does not depend on cables to connect each endpoint, deploying WiMax to an entire high rise, community or campus can be done in a matter of a couple of days, saving significant amounts of manpower.

Networks > Geographical Spread / Distance: Local Area

Network (LAN)

Networks can be divided into three types based on geographical areas covered, namely: LANs, MANs and WANs LAN: Local Area Network

Features: 1) LAN typically connects computers within a single building or campus. 2) LAN was developed in 1970s 3) Its restricted in size and hence the worst case transmission time is known in advance 4) It uses a singl cable transmission technoology to which all computers are attached 5) The medium used here is optical fibres, coaxial cables, twisted pair, wireless 6) It offers low latency (delay) except during peak trafficepe periods 7) LANs are high speed networks with data transmission speeds ranging fromf 0.2 to 100Mbps 8) The LAN speeds are adequate for most of the distibuted stystems 9) LANs use Ethernet as their protocol

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

Networks > Geographical Spread / Distance: Metropolitan Area

Network (MAN)

Features: 1) 2) 3) 4) 5) 6) 7) 8) 9) 10)

MAN generally covers towns and cities (50 kms) Developed in 1980s The Medium used in MAN are optic fibres and cables MAN offers data transmission rates that are adequate for distributed computing Supports Data and Voice (e.g. Local Cable TV) MAN has one or two cables and no switching elements MAN has a broadcast medium to which all computers are attached IT is a simple network design MAN offers typical latencies of less than 1 msec (millisecond) Message routing in a MAN is fast

Networks > Geographical Spread / Distance: Wide Area

Network (WAN)

Features: 1) WAN was developed in 1960s 2) A WAN is made up of numerous cables and telephone lines each connecting to a pair of routers 3) WAN generally covers large distances (states, countries, continents) 4) WAN uses communication circuits connected by routers as the medium of networking 5) Routers forward packets from one to another following a router from the sender to the receiver 6) WAN offers typical latencies of 100 msec to 500 msec 7) There can be delays in communication if the WAN uses satellites 8) The typical speeds offered by WANs range from about 20 to 2000 Kbps 9) WANs are not yet suitable for distributed computing however new webstandards and networking standards are enabling WANs to be better and more robust

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MET Part Time MBA – Answers to Questions in the Question Bank (Class Notes 2007) -- Author: Prof. Max William DCosta ([email protected])

Networks > Topology The physical topology of a network refers to the configuration of cables, computers, and other peripherals. Physical topology should not be confused with logical topology which is the method used to pass information between workstations. Main Types of Network Topologies In networking, the term "topology" refers to the layout of connected devices on a network. This article introduces the standard topologies of computer networking. One can think of a topology as a network's virtual shape or structure. This shape does not necessarily correspond to the actual physical layout of the devices on the network. For example, the computers on a home LAN may be arranged in a circle in a family room, but it would be highly unlikely to find an actual ring topology there. Network topologies are categorized into the following basic types: • • • • • •

Star Topology Ring Topology Bus Topology Tree Topology Mesh Topology Hybrid Topology

More complex networks can be built as hybrids of two or more of the above basic topologies.

Networks > Topology: BUS

Topology

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