1. Business Data Communications & Networking Introduction to Data Communications Lecture 1

2. Business Data Communications & Networking Shifting of Management’s Focus zIn the 70’s management had to understand and exploit the new data processing technologies (functionality and performance) to improve efficiency zIn the 90’s effective management, use and communication of information are essential for business to remain competitive and cost effective with the increase pace of network expenditure

3. Business Data Communications & Networking The Causes Behind zCosts of computing equipment drops zIt is tempting to buy a number of overlapping products and to decentralise the procurement authority to the departmental level zVariety of software available has also increased dramatically zMakes the problems of managing and coordinating computing resources more difficult

4. Business Data Communications & Networking Manager’s Role in Managing I.T. Resources zI.T. has to be managed like other resources zManagers are most concerned about yNetwork reliability yLower rates yBusiness practices yState-of-the-Art yNew Services provided by their network service providers

5. Business Data Communications & Networking Tasks of Network Management zPerformance zCost Control/Accounting Management zInventory/Configuration/Name Management zSystem Integrity which includes Faults, Security/Privacy and Vulnerability zPlanning/Design

6. Business Data Communications & Networking Factors Affecting Network Integrity zThe trend is toward larger, more complex networks supporting more equipment and applications and more users zThe network and its associated resources and distributed applications become indispensable to the organisation zMore things can go wrong, disabling the network or degrading performance to an unacceptable level

7. Business Data Communications & Networking Managing Communications zThere is uneasy relationship between technologists and general management that hinders the effective business use of the communications systems zManagers who can bridge this gap are valuable and difficult to find zManagers must develop good information communications strategy and architecture in a business environment

8. Business Data Communications & Networking Skills Required to Manage Communications zDevelop skills to quantitatively analyse proposals and applications made by engineers and vendors and to interpret them to general management zHelps managers to oversee business communications operations

9. Business Data Communications & Networking Why Study Data Communications? zWe have moved into an information society dominated by computers, data communications, and highly skilled individuals... zAt no other time in our history, has success (whether individual, corporate, or national) depended so heavily on intelligence and information.

10. Business Data Communications & Networking Why Study Data Communications? zThe key technology of the information age is communications. zData communications and networking is a truly global area of study, both because the technology enables global communication, and because new technologies and applications often emerge from a variety of countries and spread rapidly around the world.

11. Business Data Communications & Networking Data Communications zData Communications The movement of computer information from one point to another by means of electrical or optical transmission systems. Such systems are often called data communications networks. zTelecommunications Includes the transmission of voice and video as well as data.

12. Business Data Communications & Networking Components of a Network zServer (or Host computer) Central computer in the network, storing data or software that can be accessed by the clients. zClient The input/output hardware device at the other end of a communications circuit. zCircuit The pathway through which the messages travel.

13. Business Data Communications & Networking Components of a Network

14. Business Data Communications & Networking Components of a Network zPeer-to-peer networks Do not need a server or host, but are designed to connect similar computers which share their data and software with each other. Microcomputer networks are connected by a hub and cables (circuit). A router is used to connect two or more networks, enabling computers on one network to communicate with computers on other networks (e.g. the Internet).

15. Business Data Communications & Networking Types of Networks Networks can be classified in many different ways. One of the most common is by geographic scope: yLocal Area Networks (LAN) yBackbone Networks (BNs) yMetropolitan Area Networks (MANs) yWide Area Networks (WANs)

16. Business Data Communications & Networking Types of Networks

17. Business Data Communications & Networking Types of Networks Local Area Networks (LAN) yA group of microcomputers of terminals located in the same general area and connected by a common circuit. yCovers a clearly defined small area, such as within or between a few buildings, ySupport data rates of 10 to 100 million bits per second (Mbps).

18. Business Data Communications & Networking Types of Networks Backbone Network (BN) yA larger, central network connecting several LANs, other BNs, metropolitan area networks, and wide area networks. yTypically span up to several miles. ySupport data rates from 64 Kbps to 45 Mbps.

19. Business Data Communications & Networking Types of Networks Metropolitan Area Network (MAN) yConnects LANs and BNs located in different areas to each other and to wide area networks. yTypically span from 3 - 30 miles. ySupports data rates of 100 to 1000 Mbps.

20. Business Data Communications & Networking Types of Networks Wide Area Network (WAN) yConnects BNs and MANs and are usually leased from inter-exchange carriers. yTypically span hundreds or thousands of miles. ySupports data rates of 28.8 Kbps to 2 Gbps.

21. Business Data Communications & Networking Network Model zA method of describing and analyzing data communications networks, by breaking the entire set of communications functions into a series of layers, each of which can be defined separately. zThis allows vendors to develop software and hardware to provide the functions separately.

22. Business Data Communications & Networking Networking Model zOpen System Interconnection (OSI) Model, developed in 1984, helped change the face of network computing. zOther models like TCP/IP have become more prominent in the design of networks and network technology.

23. Business Data Communications & Networking Networking Model

24. Business Data Communications & Networking Simplified Network Model Application layer (Layer 4) yThe application software used by the network user, allows the user to define what message are sent over the network.

25. Business Data Communications & Networking Simplified Network Model Network layer (Layer 3) yTakes the message generated by the application layer and performs three functions before passing them to the data link layer. 1. Translates the destination of the message into an address understood by the network. 2. If multiple routes possible, it decides which routes to take. 3. Collects message accounting information that can be used to identify how many messages each user has sent and to track errors.

26. Business Data Communications & Networking Simplified Network Model Data link layer (Layer 2) yTakes the message generated by the network layer and performs three functions before passing the message on the physical layer. 1. It controls the physical layer by deciding when to transmit messages over the media. 2. It formats the message by indicating where messages start and end, and which part is the address. (It may break it into smaller packets). 3. It detects and corrects any errors that have occurred in the transmission of the message.

27. Business Data Communications & Networking Simplified Network Model Physical layer (Layer 1) yThe physical connection between the sender and receiver. yIt transfers a series of electrical, radio, or light signals through the circuit from sender to receiver. yIt specifies the type of connection, and the signals that pass through it.

28. Business Data Communications & Networking Network Models zFor Communications to be successful, each layer in one computer must be able to communicate with its matching layer in the other computer. zThis is accomplished by standards.

29. Business Data Communications & Networking The Importance of Standards zStandards are necessary in almost every business and public service entity. zThe primary reason for standards is to ensure that hardware and software produced by different vendors can work together. zThe use of standards makes it much easier to develop software and hardware that link different networks because software and hardware can be developed one layer at a time.

30. Business Data Communications & Networking The Standards Making Process Two types of standards: yFormal standards are developed by an official industry or government body. yDefacto standards emerge in the marketplace and supported by several vendors, but have no official standing.

31. Business Data Communications & Networking The Standards Making Process Formal standardization process has three stages 1. Specification stage: developing a nomenclature and identifying the problems to be addressed. 2. Identification of choices stage: those working on the standard identify the various solutions and choose the optimum solution from among the alternatives. 3. Acceptance, the most difficult stage: defining the solution and getting recognized industry leaders to agree on a single, uniform solution

32. Business Data Communications & Networking Telecommunications Standards Organizations zInternational Organization for Standards (ISO) yMember of the ITU, makes technical recommendations about data communications interfaces.

33. Business Data Communications & Networking Telecommunications Standards Organizations zInternational Telecommunications Union - Telecommunication Standardization Sector (ITU-TSS) yTechnical standard setting organization of the UN ITU. Formerly called the Consultative Committee on International Telegraph and Telephone (CCITT) yComprised of representatives of over 150 Postal Telephone and Telegraphs (PTTs), like AT&T, RBOCs, or common carriers.

34. Business Data Communications & Networking TC Standards Organizations yAmerican National Standards Institute (ANSI) yInstitute of Electrical and Electronics Engineers (IEEE) yElectronic Industries Association (EIA) yNational Institute of Standards and Technology (NIST) yNational Exchange Carriers Association (NECA) yCorporation for Open Systems (COS) yElectronic Data Interchange -(EDI) of Electronic Data Interchange for Administration Commerce and Transport (EDIFACT).

35. Business Data Communications & Networking Future Trends Between now and the year 2010, data communications will grow faster and become more important than computer processing itself. There are three major trends driving the future of communications and networking: yPervasive Networking yThe Integration of Voice, Video and Data yNew Information Services

36. Business Data Communications & Networking Pervasive Networking zIn the future, communications networks will be everywhere. zThis pervasive networking means that virtually any computer will be able to communicate with any other computer in the world. zThis will increase telecommuting in which employees perform some or all of their work at home instead of going to the office each day.

37. Business Data Communications & Networking Pervasive Networking zCellular telephone networks will begin to compete directly with the current wired telephone network. zPervasive networking will also increase the use of electronic data interchange (EDI), the paperless transmission of business documents between companies. zThe Internet has experienced such rapid growth that it now connects millions of computers in virtually every country in the world.

38. Business Data Communications & Networking The Integration of Voice, Video and Data zThe integration of voice and data is largely complete in wide area networks. zThe integration of video into computer networks has been much slower, partly due to past legal restrictions, and partly due to the immense communications needs of video.

39. Business Data Communications & Networking New Information Services zThe World Wide Web has changed the nature of computing so now that almost anyone with a computer can be their own publisher. zNever before in the history of the human race has so much knowledge and information been available to ordinary citizens.