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E-Commerce Chapter3a


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E-Commerce Chapter3a

  1. 1. CHAPTER 3 The Internet and World WideWeb: E-commerce InfrastructureCopyright © 2002 Pearson Education, Inc. Slide 3-1
  2. 2. The Internet: TechnologyBackground  Internet  An interconnected network of thousands of networks and millions of computers linking businesses, educational institutions, government agencies, and individuals together  World Wide Web (WWW)  One of the Internet’s most popular services, providing access to over one billion Web pages Slide 3-2
  3. 3. Stages in the Development of theInternet Slide 3-3
  4. 4. Stages in the Development of theInternet Innovation Phase, from 1961 to 1974  fundamental building blocks of the Internet were conceptualized and then realized in actual hardware and software  Such as packet-switching hardware, client/server computing, and a communications protocol called TCP/IP Slide 3-4
  5. 5. Stages in the Development of theInternet Institutionalization Phase, from 1975 to 1994  DOD & NSF provided funding and legitimization for the invention called the Internet  ARPANET, NSFNET  Commercialization Phase, from 1995 to the present  Govt. agencies encouraged private corp. to take over & expand both the Internet backbone & local service to ordinary citizens Slide 3-5
  6. 6. Wide Area Network A WAN is a network that connects computers and other devices over a distances longer than 1,000 meters. Early LAN connected to dumb terminals in the same building(less than 1000 meters) to centralized mainframe computers. The new WAN proposed in 1960s were much more powerful: these new networks promised to permit to transfer entire files, send email messages, and executed programs on local computerBackbone “Backbone” refers to the U.S. domestic trunk lines that carry the heavy traffic across the nation, from one metropolitan area to another. Slide 3-6
  7. 7. Development of the Internet: Timeline Slide 3-7
  8. 8. Development of the Internet: Timeline Slide 3-8
  9. 9. Development of the Internet: Timeline Slide 3-9
  10. 10. Development of the Internet: Timeline Slide 3-10
  11. 11. Development of the Internet: Timeline Slide 3-11
  12. 12. Development of the Internet: Timeline Slide 3-12
  13. 13. The Internet: Key Technology Concepts Slide 3-13
  14. 14. The Internet: Key TechnologyConcepts  Packet switching  A method of slicing digital messages into packets, sending the packets along different communication paths as they become available, and then reassembling the packets once they arrive ate their destination  Packet  The parcels into which digital messages are sliced for transmission over the Internet Slide 3-14
  15. 15. The Internet: Key TechnologyConcepts  Routers  Special-purpose computers that interconnect the computer networks that make up the Internet and route packets to their ultimate destination as they travel the Internet  Routing algorithm  Computer program that ensures packets take the best available path toward their destination Slide 3-15
  16. 16. Packet Switching Slide 3-16
  17. 17. The Internet: Key TechnologyConcepts  TCP (Transmission Control Protocol  Protocol that establishes the connections among sending and receiving Web computers, handles the assembly of packets at point of transmission, and their reassembly at the receiving end  IP (Internet Protocol)  Protocol that provides the Internet’s addressing scheme  Protocol  A set of rules for formatting, ordering, compressing, and error checking messages Slide 3-17
  18. 18. TCP/IP Architecture and Protocol Suiteis an industry-standard suite of protocols for large internetworks Slide 3-18
  19. 19. TCP/IP Architecture Layers Network Interface Layer  responsible for placing packets on and receiving them from the network medium Internet Layer  responsible for addressing, packaging, and routing messages on the Internet Transport Layer  responsible for providing communication with the application by acknowledging and sequencing the packets to and from the application Application Layer  provides a wide variety of applications with the ability to access the services of the lower layers Slide 3-19
  20. 20. IP Addresses  Internet addresses expressed as 32-bit numbers that appear as a series of four separate numbers marked off by periods, such as  In the current IPv4, each of the four numbers can range from 0 to 255 allowing for up to 4 billion addresses  In IPv6, the next generation IP, the scheme uses 128-bit addresses, or about one quadtrillion addresses Slide 3-20
  21. 21. Routing Internet Messages: TCP/IPand Packet SwitchingPage 119, Figure 3.6 Slide 3-21
  22. 22. Domain Names and URLs  Domain name  IP address expressed in natural language  Domain name system (DNS)  System for expressing numeric IP addresses in natural language  Uniform resource locator (URL)  The address used by a Web browser to identify the location of content on the Web Slide 3-22
  23. 23. Slide 3-23
  24. 24. Pieces of the Internet Puzzle:Names and Addresses Slide 3-24
  25. 25. Client/Server Computing  Client/server  A model of computing in which very powerful personal computers are connected together in a network with one or more servers.  Client  A very powerful personal computer that is part of a network. They are capable of displaying rich graphics, storing large files, and processing graphics and sound files.  Server  Networked computer dedicated to common functions that the client machines on the network need, such as storing files, software applications, utility programs such as Web connections, and printers. Slide 3-25
  26. 26. The Client/Server Computing Model Slide 3-26
  27. 27. Other Internet Protocols and UtilityPrograms  HTTP is the Internet protocol used for transferring Web pages.  FTP is one of the original Internet services. Part of TCP/IP protocol that permits users to transfer files from the server to their client machine, and vice versa  SSL is a protocol that provides secure communications between the client and the server Slide 3-27
  28. 28. Other Internet Protocols and UtilityPrograms  Sending E-mail  SMTP (Simple Mail Transfer Protocol) is the Internet protocol used to send mail to a server  POP (Post Office Protocol) is a protocol used by the client to retrieve mail from an Internet server  IMAP (Internet Mail Access Protocol) is a more current e-mail protocol that allows users to search, organize, and filter their mail prior to downloading it from the server Slide 3-28
  29. 29. Other Internet Protocols and UtilityPrograms  Telnet is a terminal emulation program that runs in TCP/IP  Finger is a utility program supported by UNIX computers that tells who is logged in, how long they have been attached, and their user name  Ping is a program that allows you to check the connection between your client and the server  Tracerout is one of several route-tracing utilities that allow you to follow the path of a message you send from your client to a remote computer on the Internet Slide 3-29
  30. 30. Tracing the Route a Message Takeson the Internet Slide 3-30
  31. 31. Internet I Network Architecture Slide 3-31
  32. 32. The Internet Backbone Backbone  high-bandwidth fiber optic cable that transports data across the Internet Network Service Provider (NSP)  owns and controls one of the major networks comprising the Internet’s backbone Slide 3-32
  33. 33. Major U.S. Internet BackboneOwners Slide 3-33
  34. 34. The Internet Backbone Bandwidth  measures how much data can be transferred over a communications medium within a fixed period of time; is usually expressed in bits per second (bps), kilobits per second (Kbps), or megabits per second (Mbps) Redundancy  multiple duplicate devices or paths in a network Slide 3-34
  35. 35. Network Access Points andMetropolitan Area Exchanges Network Access Point (NAP)  one of the hubs where the backbone intersects with regional and local networks, and where the backbone owners connect with one another Metropolitan Area Exchanges (MAEs)  another name for one of the hubs where the backbone intersects with regional and local networks Slide 3-35
  36. 36. Internet NAPS and MAES Slide 3-36
  37. 37. Internet NAPSand MAESPage 128, Figure 3.13 Slide 3-37
  38. 38. Campus Networks  Generally local area networks operating with a single organization that leases access to the Web directly from regional and national carriers Slide 3-38
  39. 39. Internet Service Providers  Firm that provides the lowest level of service in the multi-tiered Internet architecture by leasing Internet access to home owners, small businesses, and some large institutions  Narrowband  The traditional telephone modem connections, now operating at 56.6 Kbps  Broadband  refers to any communication technology that permits clients to play streaming audio and video files at acceptable speeds -- generally above 100 Kbps Slide 3-39
  40. 40. ISP Service Level ChoicesPage 130, Table 3.3 Slide 3-40
  41. 41. ISP Service Level Choices Digital Subscriber Line (DSL)  a telephone technology for delivering high-speed access through ordinary telephone lines found in homes and businesses cable modem  a cable television technology that piggybacks digital access to the Internet on top of the analog video cable providing television signals to a home Slide 3-41
  42. 42. ISP Service Level Choices  T1  an international telephone standard for digital communication that offers guaranteed delivery at 1.54 Mbps  T3  an international telephone standard for digital communication that offers guaranteed delivery at 43 Mbps Slide 3-42
  43. 43. Time to Download a 10 MegabyteFile by Type of Internet Service Slide 3-43
  44. 44. Intranets and Extranets  Intranet  a TCP/IP network located within a single organization for purposes of communications and information processing  Extranet  formed when firms permit outsiders to access their internal TCP/IP networks Slide 3-44
  45. 45. Who Governs the Internet?  Internet Architecture Board (IAB)  Internet Corporation for Assigned Names and Numbers (ICANN)  Internet Engineering Steering Group (IESG)  Internet Engineering Task Force (IETF)  Internet Society (ISOC)  World Wide Web Consortium (W3C) Slide 3-45
  46. 46. Chapter 3 continued on file name ch03b.ppt Slide 3-46