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  1. 1. Fundamentals of Business Data Communications 11th EditionAlan Dennis & Alexandra Durcikova John Wiley & Sons, Inc Dwayne Whitten, D.B.A Mays Business School Texas A&M University Copyright 2011John Wiley & Sons, Inc. 1-1
  2. 2. Chapter 1Introduction to Data Communications Copyright 2011John Wiley & Sons, Inc. 1-2
  3. 3. Chapter 1 Outline1.1 – Introduction – Brief history of Data Communications, Communications, Information Systems and the Internet1.2 - Data Communications Networks – Network components, network types1.3 - Network Models – OSI model, Internet model, transmission via “layers”1.4 - Network Standards – Standards making, common standards1.5 - Future Trends – Pervasive networking, integration of voice, video, and data, new information services 1.6 – Implications for Management Copyright 2011John Wiley & Sons, Inc. 1-3
  4. 4. 1.1 Introduction Copyright 2011John Wiley & Sons, Inc. 1-4
  5. 5. Information Age• First Industrial Revolution – Introduction of machinery – New organizational methods – Changed the way people worked• Second Industrial Revolution – Information Age – Introduction of computers – Introduction of networking and data communication – Changed the way people worked again • Faster communication  Collapsing Information lag • Brought people together  Globalization Copyright 2011John Wiley & Sons, Inc. 1-5
  6. 6. The Collapsing Information Lag Historical developments in sped up the rate and volume of electronic communications transmission of informationtelegraph 1850 1900 1950 2009 Information took days Information large quantities of or weeks to be transmitted in information transmitted in transmitted minutes or hours a fraction of a second growth of telecommunications and especially computer networks Globalization of networks Copyright 2011John Wiley & Sons, Inc. 1-6
  7. 7. Three Parts to Understanding Networking1. Concepts of networking – How data moves from one computer to another over a network – Theories of how networks operate2. Technologies in use today – How theories are implemented, specific products – How do they work, their use, applications3. Management of networking technologies – Security – Network Design – Managing the network Copyright 2011John Wiley & Sons, Inc. 1-7
  8. 8. Advances in Phone Technology first trans- Telstar continental (Telecommunications Packet-switched and via satellite), Fax data transatlantic services, digital communications Phone phone transmission (T-invented connections carriers)1876 1915 1948 1962 1976 1919 1969 1984 Strowger (stepper) Microwave switch, trunk lines Picturefone Cellular rotary dial phones (Canada) (failed telephone (enabling automatic commercially) connections) Copyright 2011John Wiley & Sons, Inc. 1-8
  9. 9. Regulation of Inventions FCC established A time for Regulation Carterfone court technological began in the decision allowing Deregulation change USA (ICC) non-Bell CPE period1876 1885 1900 1910 1934 1968 1996 AT&T 1970 1984Phone Bell System:invented (rapid Consent de factoacceptance) decree by US monopoly federal court millions of phones MCI wins court case; 1996 US in use in the US begins providing some Telecom long distance services Act Copyright 2011John Wiley & Sons, Inc. 1-9
  10. 10. 1984 Consent DecreeDivestiture of 1/1/84: RBOC’s• AT&T broken up into one long distance company (AT&T) and 7 Regional Bell Operating Companies (RBOC’s) South US West AT&T Western Bell Bell Atlantic Pacific Bell NYNEX AT&T Ameritech Bell SouthDeregulation: IXC’s and LEC’s • Competitive long distance (IXC) market; MCI & Sprint enter long distance telephone market (among others) • Local Exchange Carrier (LEC) service markets remained under RBOC monopoly Copyright 2011John Wiley & Sons, Inc. 1 - 10
  11. 11. US Telecom Act of 1996• Replaced all current laws, FCC regulations, 1984 consent decree, and overrules state laws• Main goal: open local markets to competition• To date, though, local and long distance competition slow to take hold – Large IXCs expected to move into the local markets, happening only recently – Likewise, RBOCs expected to move into long distance markets, happening only recently Copyright 2011John Wiley & Sons, Inc. 1 - 11
  12. 12. Worldwide Competitive Markets• Internet market – Extremely competitive with more than 5000 Internet Service Providers (ISPs) in the US alone. – Heavy competition in this area may lead to a shake out in the near future.• World Trade Organization (WTO) agreement (1997) – commitments by 68 countries to open, deregulate or lessen regulation in their telecom markets• Multi-national telecom companies – US companies offering services in Europe, South America – European companies offering services in USA Copyright 2011John Wiley & Sons, Inc. 1 - 12
  13. 13. History of Information Systems Online real-time, transaction oriented PC LANs Batch systems (replaced batchprocessing becomemainframes processing. DBMSs common become common)1950 1960 1970 1980 1990 2000 PC revolution Data communications over Networking phone lines (became everywhere common and mainframes became multi-user systems) Copyright 2011John Wiley & Sons, Inc. 1 - 13
  14. 14. Internet Milestones NSFNet commercialOriginally called created asARPANET, the Internet access to US Internet the Internetbegan as a military-academic network backbone begins 1969 1983 1986 1990 1994 2007 ARPANET splits: Government Worldwide: • Milnet - for military funding of the Over 1 billion • Internet - academic, backbone Internet users education and research ends purposes only Copyright 2011John Wiley & Sons, Inc. 1 - 14
  15. 15. Net NeutralityNet neutrality means that for a given type of content (i.e. email,web, video, etc), all content providers are treated the same.Net neutrality prevents ISPs from giving priority to some contentproviders, while slowing down others Copyright 2011John Wiley & Sons, Inc. 1 - 15
  16. 16. 1.2 Data Comm NetworksTelecommunications = Data Communications =Transmission of voice, video, Movement of computerand/or data information by means of electrical- Implies longer distances or optical transmission systems- Broad term convergence Broadband Communications Copyright 2011John Wiley & Sons, Inc. 1 - 16
  17. 17. Components of a Local Area Network Copyright 2011John Wiley & Sons, Inc. 1 - 17
  18. 18. Network Types (based on Scale)• Local Area Networks (LAN) - room, building – a group of PCs that share a circuit.• Backbone Networks (BN) - less than few kms – a high speed backbone linking together organizational LANs at various locations.• Metropolitan Area Networks (MAN) - (more than a few kms) – connects LANs and BNs across different locations – Often uses leased lines or other services used to transmit data.• Wide Area Networks (WANs) - (far greater than 10 kms) – Same as MAN except wider scale Copyright 2011John Wiley & Sons, Inc. 1 - 18
  19. 19. LANs and Backbones, Wide Area and Metropolitan Area Networks Copyright 2011John Wiley & Sons, Inc. 1 - 19
  20. 20. Intranet vs. Extranet• Intranet – A LAN that uses the Internet technologies within an organization – Open only those inside the organization – Example: insurance related information provided to employees over an intranet• Extranet – A LAN that uses the Internet technologies across an organization including some external constituents – Open only those invited users outside the organization – Accessible through the Internet – Example: Suppliers and customers accessing inventory information in a company over an extranet Copyright 2011John Wiley & Sons, Inc. 1 - 20
  21. 21. Layered Implementation of Communications Functions Single layer Applications Applications implementation -Networking with OS large components OS is complex to understand and implementApplications Applications Multi layer implementation OS OS -Breaking down into smaller components -Easier to implement Copyright 2011John Wiley & Sons, Inc. 1 - 21
  22. 22. 1.3 Multi-layer Network Models• The two most important such network models: OSI and Internet• Open Systems Interconnection Model – Created by International Standards Organization (ISO) as a framework for computer network standards in 1984 – Based on 7 layers• Internet Model – Created by DARPA originally in early 1970’s – Developed to solve to the problem of internetworking – Based on 5 layers – Based on Transmission Control Protocol/ Internet Protocol (TCP/IP) suite Copyright 2011John Wiley & Sons, Inc. 1 - 22
  23. 23. 7-Layer Model of OSIPhysical DataLink Network Transport Session Presentation Application “Please Do Not Touch Steve’s Pet Alligators” • Application Layer – set of utilities used by application programs • Presentation Layer – formats data for presentation to the user – provides data interfaces, data compression and translation between different data formats • Session Layer – initiates, maintains and terminates each logical session between sender and receiver Copyright 2011John Wiley & Sons, Inc. 1 - 23
  24. 24. 7-Layer Model of OSI• Transport Layer – deals with end-to-end issues such as segmenting the message for network transport, and maintaining the logical connections between sender and receiver• Network Layer – responsible for making routing decisions• Data Link Layer – deals with message delineation, error control and network medium access control• Physical Layer – defines how individual bits are formatted to be transmitted through the network Copyright 2011John Wiley & Sons, Inc. 1 - 24
  25. 25. Internet’s 5-Layer Model Physical DataLink Network Transport Application “Please Do Not Touch Alligators”• Application Layer – used by application program• Transport Layer – responsible for establishing end-to-end connections, translates domain names into numeric addresses and segments messages• Network Layer - same as in OSI model• Data Link Layer - same as in OSI model• Physical Layer - same as in OSI model Copyright 2011John Wiley & Sons, Inc. 1 - 25
  26. 26. Comparison of Network Models Copyright 2011John Wiley & Sons, Inc. 1 - 26
  27. 27. Message Transmission Using Layers Copyright 2011John Wiley & Sons, Inc. 1 - 27
  28. 28. Protocols• Used by network model layers• Sets of standardized rules to define how to communicate at each layer and how to interface with adjacent layers Layer N+1 Layer N+1 Layer N Layer NLayer N-1 Layer N-1 sender receiver Copyright 2011John Wiley & Sons, Inc. 1 - 28
  29. 29. Message Transmission Example Copyright 2011John Wiley & Sons, Inc. 1 - 29
  30. 30. Points about Network Layer View• Layers allow simplicity of networking in some ways – Easy to develop new software that fits each layer – Relatively simple to change the software at any level• Matching layers communicate between different computers and computer platforms – Accomplished by standards that we all agree on – e.g., Physical layer at the sending computer must match up with the same layer in the receiving computer• Somewhat inefficient – Involves many software packages and packets – Packet overhead (slower transmission, processing time) – Interoperability achieved at the expense of perfectly streamlined communication Copyright 2011John Wiley & Sons, Inc. 1 - 30
  31. 31. 1.4 Network Standards• Importance – Provide a “fixed” way for hardware and/or software systems (different companies) to communicate – Help promote competition and decrease the price• Types of Standards – Formal standards • Developed by an industry or government standards- making body – De-facto standards • Emerge in the marketplace and widely used • Lack official backing by a standards-making body Copyright 2011John Wiley & Sons, Inc. 1 - 31
  32. 32. Standardization Processes• Specification – Developing the nomenclature and identifying the problems to be addressed• Identification of choices – Identifying solutions to the problems and choose the “optimum” solution• Acceptance – Defining the solution, getting it recognized by industry so that a uniform solution is accepted Copyright 2011John Wiley & Sons, Inc. 1 - 32
  33. 33. Major Standards Bodies• ISO (International Organization for Standardization) – Technical recommendations for data communication interfaces – Composed of each country’s national standards orgs. – Based in Geneva, Switzerland (• ITU-T (International Telecommunications Union – Telecom Group – Technical recommendations about telephone, telegraph and data communications interfaces – Composed of representatives from each country in UN – Based in Geneva, Switzerland ( Copyright 2011John Wiley & Sons, Inc. 1 - 33
  34. 34. Major Standards Bodies (Cont.)• ANSI (American National Standards Institute) – Coordinating organization for US (not a standards- making body) –• IEEE (Institute of Electrical and Electronic Engineers) – Professional society; also develops mostly LAN standards –• IETF (Internet Engineering Task Force) – Develops Internet standards – No official membership (anyone welcome) – Copyright 2011John Wiley & Sons, Inc. 1 - 34
  35. 35. Some Data Comm. Standards Layer Common Standards HTTP, HTML (Web)5. Application layer MPEG, H.323 (audio/video) IMAP, POP (e-mail)4. Transport layer TCP (Internet) SPX (Novell LANs)3. Network layer IP (Internet) IPX (Novell LANs) Ethernet (LAN)2. Data link layer Frame Relay (WAN) T1 (MAN and WAN) RS-232c cable (LAN)1. Physical layer Category 5 twisted pair (LAN) V.92 (56 kbps modem) Copyright 2011John Wiley & Sons, Inc. 1 - 35
  36. 36. 1.5 Future Trends• Pervasive Networking• Integration of Voice, Video and Data• New Information Services Copyright 2011John Wiley & Sons, Inc. 1 - 36
  37. 37. Pervasive Networking• Means “Networks will be everywhere”• Exponential growth of Network use• Many new types of devices will have network capability• Exponential growth of data rates for all kinds of networking• Broadband communications – Use circuits with 1 Mbps or higher (e.g., DSL) Copyright 2011John Wiley & Sons, Inc. 1 - 37
  38. 38. Relative Capacities ofTelephone, LAN, BN, WAN, and Internet Circuits.
  39. 39. Integration of Voice, Video & Data• Also called “Convergence” – Networks that were previously transmitted using separate networks will merge into a single, high speed, multimedia network in the near future• First step largely complete – Integration of voice and data• Next step – Video merging with voice and data – Will take longer partly due to the high data rates required for video Copyright 2011John Wiley & Sons, Inc. 1 - 39
  40. 40. New Information Services• World Wide Web based – Many new types of information services becoming available • Services that help ensure quality of information received over www• Application Service Providers (ASPs) – Develop specific systems for companies such as providing and operating a payroll system for a company that does not have one of its own• Information Utilities (Future of ASPs) – Providing a wide range of info services (email, web, payroll, etc.) (similar to electric or water utilities) Copyright 2011John Wiley & Sons, Inc. 1 - 40
  41. 41. 1.6 Implications for Management• Embrace change and actively seek to use new aspects of networks toward improving your organization – Information moved quickly and easily anywhere and anytime – Information accessed by customers and competitors globally• Use a set of industry standard technologies – Can easily mix and match equipment from different vendors – Easier to migrate from older technologies to newer technologies – Smaller cost by using a few well known standards Copyright 2011John Wiley & Sons, Inc. 1 - 41
  42. 42. Copyright 2011 John Wiley & Sons, Inc.All rights reserved. Reproduction or translation ofthis work beyond that permitted in section 117 ofthe 1976 United States Copyright Act withoutexpress permission of the copyright owner isunlawful. Request for further information shouldbe addressed to the Permissions Department,John Wiley & Sons, Inc. The purchaser may makeback-up copies for his/her own use only and notfor distribution or resale. The Publisher assumesno responsibility for errors, omissions, ordamages caused by the use of these programs orfrom the use of the information herein. Copyright 2011John Wiley & Sons, Inc. 1 - 42