0
Electronic Commerce         Eighth Edition              Chapter 2Technology Infrastructure: The Internet      and the Worl...
Learning ObjectivesIn this chapter, you will learn about:• The origin, growth, and current structure of the   Internet• Ho...
Learning Objectives (cont’d.)• How HTML tags and links work on the World Wide  Web• The differences among internets, intra...
The Internet and the World Wide Web• Computer network      – Technology allowing people to connect computers      – Intern...
Origins of the Internet• Early 1960s      – Defense Department nuclear attack concerns      – Used powerful computers (lar...
New Uses for the Internet• Defense Department network use was original goal      – Control weapons systems, transfer resea...
New Uses for the Internet (cont’d.)• Game-playing software created• Limited Internet use      – Research and academic comm...
Commercial Use of the Internet• National Science Foundation (NSF)      – Provided funding      – Prohibited commercial net...
Growth of the Internet• 1991      – Further easing of commercial Internet activity        restrictions• 1995: privatizatio...
Electronic Commerce, Eighth Edition   10
Growth of the Internet (cont’d.)• Internet hosts: directly connected computers• Internet growth     –   Technological and ...
Emergence of the World Wide Web• Web      – Software running on Internet-connected computers      – Generates Internet tra...
Emergence of the World Wide Web                 (cont’d.)• The development of hypertext      – 1945: Vannevar Bush: The At...
Emergence of the World Wide Web                 (cont’d.)• The development of hypertext (cont’d.)      – 1989: Tim Berners...
Emergence of the World Wide Web                 (cont’d.)• The development of hypertext (cont’d.)      – HTML           • ...
Emergence of the World Wide Web                 (cont’d.)• Graphical interfaces for hypertext      – Web browser          ...
Emergence of the World Wide Web                 (cont’d.)• The World Wide Web      – Berners-Lee’s system of hyperlinked H...
Emergence of the World Wide Web                 (cont’d.)• The World Wide Web (cont’d.)      – Easy way to access Internet...
• Estimates      – More than 140 million Web sites      – More than 30 billion individual Web pages• Commercial business W...
Packet-Switched Networks• Local area network (LAN)      – Network of computers located close together• Wide area networks ...
Packet-Switched Networks (cont’d.)• Circuit switching (cont’d.)      – Works well for telephone calls      – Does not work...
Packet-Switched Networks (cont’d.)• Packet-switched network      – Packets           • Small pieces labeled electronically...
Routing Packets• Routing computers      – Decide how best to forward each packet      – Router computers, routers, gateway...
Routing Packets (cont’d.)• Routing algorithms applied to routing table  information• Routing tables (configuration tables)...
• Internet backbone      – Internet routers handle packet traffic along main        connecting points (backbone routers)  ...
Internet Protocols• ARPANET: Network Control Protocol (NCP)• Protocol: collection of network data rules      – Includes tr...
TCP/IP• Internet protocols      – Transmission Control Protocol (TCP)           • Controls message, file disassembly into ...
IP Addressing• Internet Protocol version 4 (IPv4)      – Used for past 20 years• IP address      – 32-bit number identifyi...
IP Addressing (cont’d.)• Dotted decimal notation      – IP numbers (addresses)           • Four numbers separated by perio...
IP Addressing (cont’d.)• High demand for IP addresses• Subnetting      – Use reserved private IP LAN (WAN) addresses      ...
IP Addressing (cont’d.)• Internet Protocol version 6 (IPv6)      – Replace IPv4 (future)           • Not directly compatib...
Domain Names• Dotted decimal notation difficult to remember• Domain names      – Sets of words assigned to specific IP add...
Electronic Commerce, Eighth Edition   33
Web Page Request and Delivery                  Protocols• Web client computers      – Web client software (Web browser sof...
Web Page Request and Delivery              Protocols (cont’d.)• Hypertext Transfer Protocol (HTTP)      – Internet Web pag...
Electronic Mail Protocols• Electronic mail (e-mail)      – Formatted according to common set of rules      – Client/server...
Electronic Mail Protocols (cont’d.)• Two common protocols      – Simple Mail Transfer Protocol (SMTP)           • Specifie...
Electronic Mail Protocols (cont’d.)• Multipurpose Internet Mail Extensions (MIME)      – Set of rules for handling binary ...
Unsolicited Commercial E-Mail                    (UCE, Spam)• Spam      – Unsolicited commercial e-mail (UCE)      – Bulk ...
Markup Languages and the Web• Text markup language      – Specifies tag set inserted into text• Markup tags (tags)      – ...
Markup Languages and the Web                   (cont’d.)• Extensible Markup Language (XML)      – Derived from SGML      –...
Electronic Commerce, Eighth Edition   42
Standard Generalized Markup                     Language• Generalized Markup Language (GML)      – Creates standard electr...
Hypertext Markup Language• Hypertext elements      – Text elements related to each other• HTML      – Prevalent markup lan...
Hypertext Markup Language (cont’d.)• HTML tags      – Interpreted by Web browser      – Format text display      – Enclose...
Hypertext Markup Language (cont’d.)• One-sided tags      – Require opening tag only• Two-sided tags      – Optional closin...
Electronic Commerce, Eighth Edition   47
Electronic Commerce, Eighth Edition   48
Hypertext Markup Language (cont’d.)• HTML links      – Hyperlinks form interlinked pages that form a “web”• Linear hyperli...
Electronic Commerce, Eighth Edition   50
Electronic Commerce, Eighth Edition   51
Hypertext Markup Language (cont’d.)• Scripting languages and style sheets• HTML version released (after 1997)      – Objec...
Extensible Markup Language (XML)• Web design tool      – Web pages contain large amounts of data, lists• Includes data-man...
Electronic Commerce, Eighth Edition   54
Electronic Commerce, Eighth Edition   55
• Figures 2-12 and 2-13      – Advantages of XML list presentation           • More effectively communicate the meaning of...
Electronic Commerce, Eighth Edition   57
Extensible Markup Language (XML)                       (cont’d.)• Strength of XML      – Allows users to define their own ...
Electronic Commerce, Eighth Edition   59
HTML and XML Editors• HTML document creation      – General-purpose text editor or word processor      – Special-purpose H...
Intranets and Extranets• internets (small “i”)      – Interconnected networks      – Do not extend beyond organizational b...
Intranets• Distribute internal corporate information      – Low-cost, efficient• Client/server model-based      – Requests...
Extranets• Connects company with suppliers, business  partners, other authorized users      – Database access, files, othe...
Public and Private Networks• Public network      – Public availability• Private network      – Private, leased-line connec...
Virtual Private Network (VPN)• Extranet using public networks and protocols      – Sends sensitive data      – Uses IP tun...
• Leased lines not required• Infrastructure required outside company’s intranet• Extranets sometimes confused with VPNs   ...
Internet Connection Options• Internet      – Set of interconnected networks• Organizations connect computers using a netwo...
Connectivity Overview• Common connection options      – Voice-grade telephone lines, various types of        broadband con...
Connectivity Overview (cont’d.)• Asymmetric connections      – Provide different bandwidths for each direction• Upstream b...
Voice-Grade Telephone Connections• Local telephone service provider      – Most common way for an individual to connect to...
Broadband Connections• Connection speeds greater than 200 Kbps      – Asymmetric digital subscriber line (ADSL)           ...
Leased-Line Connections• More expensive technologies      – Classified by equivalent number of telephone lines        incl...
Leased-Line Connections (cont’d.)• NAPs and Internet backbone use:      – Frame relay      – Asynchronous transfer mode (A...
Wireless Connections• Satellite sent microwave transmissions      – Download speeds (500 Kbps)      – Upload handled by PO...
Wireless Connections (cont’d.)• Bluetooth and Ultra Wideband (UWB)• Bluetooth design for use over short distances      – L...
Wireless Connections (cont’d.)• Wireless Ethernet (Wi-Fi)      – Wi-Fi (wireless Ethernet, 802.11b)      – Wireless access...
Wireless Connections (cont’d.)• Wireless Ethernet (Wi-Fi) (cont’d.)      – 802.11n: “Draft-N” (300 to 450 Mbps range)     ...
Wireless Connections (cont’d.)• Fixed-point wireless      – System of repeaters           • Forward radio signal from ISP ...
Wireless Connections (cont’d.)• Cellular telephone networks      – Broadcast signals to (receive signals from) antennas   ...
Electronic Commerce, Eighth Edition   80
Internet2 and the Semantic Web• Internet2      –   Replacement for original ARPANET laboratory      –   Experimental netwo...
Internet2 and the Semantic Web                     (cont’d.)• Semantic Web project (next-generation Web)      – Focus     ...
Summary• In this chapter, you were introduced to:      – History of the Internet and Web      – Hardware and software tech...
Summary (cont’d.)      – Networking technologies           • Internets, intranets, and extranets      – Types of Internet ...
Upcoming SlideShare
Loading in...5
×

PPT ch02

2,008

Published on

Published in: Business, Technology
0 Comments
2 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
2,008
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
89
Comments
0
Likes
2
Embeds 0
No embeds

No notes for slide

Transcript of "PPT ch02"

  1. 1. Electronic Commerce Eighth Edition Chapter 2Technology Infrastructure: The Internet and the World Wide Web
  2. 2. Learning ObjectivesIn this chapter, you will learn about:• The origin, growth, and current structure of the Internet• How packet-switched networks are combined to form the Internet• How Internet protocols and Internet addressing work• The history and use of markup languages on the Web, including SGML, HTML, and XMLElectronic Commerce, Eighth Edition 2
  3. 3. Learning Objectives (cont’d.)• How HTML tags and links work on the World Wide Web• The differences among internets, intranets, and extranets• Options for connecting to the Internet, including cost and bandwidth factors• Internet2 and the Semantic WebElectronic Commerce, Eighth Edition 3
  4. 4. The Internet and the World Wide Web• Computer network – Technology allowing people to connect computers – Internet • Interconnected global computer networks (large)• Basic technology structure – Computer networks and the Internet – Underlies e-commerce• World Wide Web (Web) – Subset of Internet computers • Contents easily accessible – Includes easy-to-use interfacesElectronic Commerce, Eighth Edition 4
  5. 5. Origins of the Internet• Early 1960s – Defense Department nuclear attack concerns – Used powerful computers (large mainframes) – Used leased telephone company lines • Single connection – Single connection risk solution • Communicate using multiple channels (packets)• 1969 Advanced Research Projects Agency (ARPA) – Packet network connected four computers • ARPANET: earliest network (became the Internet) • Academic research use (1970s and 1980s)Electronic Commerce, Eighth Edition 5
  6. 6. New Uses for the Internet• Defense Department network use was original goal – Control weapons systems, transfer research files• 1970s: other uses – E-mail (1972) – Networking technology • Remote file transfer and computer access – Mailing lists • E-mail address forwards message to subscribed users• 1979 Usenet (User’s News Network) – Read and post articles – Newsgroups (topic areas)Electronic Commerce, Eighth Edition 6
  7. 7. New Uses for the Internet (cont’d.)• Game-playing software created• Limited Internet use – Research and academic communities• 1979 – 1989 – Network applications improved and tested – Defense Department’s networking software • Gained wider academic and research institution use • Common communications network benefit recognized – Security problems recognized• 1980s: personal computer use explosion – Academic and research networks mergedElectronic Commerce, Eighth Edition 7
  8. 8. Commercial Use of the Internet• National Science Foundation (NSF) – Provided funding – Prohibited commercial network traffic• Business turned to commercial e-mail providers• Larger firms built networks (leased telephone lines)• 1989: NSF permitted two commercial e-mail services – MCI Mail and CompuServe • Commercial enterprises could send e-mail • Research, education communities sent e-mail directly to MCI Mail and CompuServeElectronic Commerce, Eighth Edition 8
  9. 9. Growth of the Internet• 1991 – Further easing of commercial Internet activity restrictions• 1995: privatization of the Internet – Operations turned over to privately owned companies • Internet based on four network access points (NAPs)• Network access providers – Sell Internet access rights directly to larger customers – Use Internet service providers (ISPs) • Sell to smaller firms and individualsElectronic Commerce, Eighth Edition 9
  10. 10. Electronic Commerce, Eighth Edition 10
  11. 11. Growth of the Internet (cont’d.)• Internet hosts: directly connected computers• Internet growth – Technological and social accomplishment – Used by millions of people – Thousands of different software packages – Billions of dollars change hands yearly – Led to World Wide WebElectronic Commerce, Eighth Edition 11
  12. 12. Emergence of the World Wide Web• Web – Software running on Internet-connected computers – Generates Internet traffic • Web software: largest single traffic category • Outpaces: e-mail, file transfers, other data transmission traffic – New way of thinking about information storage and retrieval• Web history important innovations – Hypertext – Graphical user interfacesElectronic Commerce, Eighth Edition 12
  13. 13. Emergence of the World Wide Web (cont’d.)• The development of hypertext – 1945: Vannevar Bush: The Atlantic Monthly article • Visionary ideas: future technology uses (Memex) – 1960s: Ted Nelson described hypertext • Page-linking system • Douglas Engelbart: experimental hypertext system – 1987: Nelson published Literary Machines • Outlined project Xanadu global system • Online hypertext publishing and commerceElectronic Commerce, Eighth Edition 13
  14. 14. Emergence of the World Wide Web (cont’d.)• The development of hypertext (cont’d.) – 1989: Tim Berners-Lee • Proposed hypertext development project • Provided data-sharing functionality • Developed hypertext server program code – Hypertext server • Stores Hypertext Markup Language (HTML) files • Computers connect and read files – Web servers (today) • Hypertext servers used on the WebElectronic Commerce, Eighth Edition 14
  15. 15. Emergence of the World Wide Web (cont’d.)• The development of hypertext (cont’d.) – HTML • Set of codes (tags) attached to text • Describes relationships among text elements – Hypertext link (hyperlink) • Points to another location • Same or another HTML documentElectronic Commerce, Eighth Edition 15
  16. 16. Emergence of the World Wide Web (cont’d.)• Graphical interfaces for hypertext – Web browser • Software interface • Users read (browse) HTML documents • Move from one HTML document to another • Text formatted with hypertext link tags in file – HTML document • No specification of text element appearance – Graphical user interface (GUI) • Presents program control functions, output to users • Pictures, icons, other graphical elementsElectronic Commerce, Eighth Edition 16
  17. 17. Emergence of the World Wide Web (cont’d.)• The World Wide Web – Berners-Lee’s system of hyperlinked HTML documents – Quick acceptance in scientific research community – 1993: first GUI program (Mosaic) • Read HTML • Used HTML hyperlinks for page-to-page navigation • First Web browser widely available for personal computersElectronic Commerce, Eighth Edition 17
  18. 18. Emergence of the World Wide Web (cont’d.)• The World Wide Web (cont’d.) – Easy way to access Internet information • Provided by functional system of pages connected by hypertext links • Profit-making potential – Netscape Communications founded in 1994 • Netscape Navigator Web browser (based on Mosaic) • Microsoft: Internet Explorer (most widely used) • Mozilla Firefox: Netscape Navigator descendant – Number of Web sites • More rapid growth than the Internet itselfElectronic Commerce, Eighth Edition 18
  19. 19. • Estimates – More than 140 million Web sites – More than 30 billion individual Web pages• Commercial business Web use increasingElectronic Commerce, Eighth Edition 19
  20. 20. Packet-Switched Networks• Local area network (LAN) – Network of computers located close together• Wide area networks (WANs) – Networks of computers connected over greater distances• Circuit – Combination of telephone lines and closed switches that connect them to each other• Circuit switching – Centrally controlled, single-connection model • Single electrical path between caller and receiverElectronic Commerce, Eighth Edition 20
  21. 21. Packet-Switched Networks (cont’d.)• Circuit switching (cont’d.) – Works well for telephone calls – Does not work as well for: • Sending data across large WAN, interconnected network (Internet)• Circuit-switched network problem – Connected circuit failure • Causes interrupted connection, data loss• Solution – Packet switching: move data between two pointsElectronic Commerce, Eighth Edition 21
  22. 22. Packet-Switched Networks (cont’d.)• Packet-switched network – Packets • Small pieces labeled electronically (origin, sequence, destination address) • Travel along interconnected networks • Can take different paths • May arrive out of order – Destination computer • Collects packets • Reassembles original file or e-mail messageElectronic Commerce, Eighth Edition 22
  23. 23. Routing Packets• Routing computers – Decide how best to forward each packet – Router computers, routers, gateway computers • Gateway from LAN (WAN to the Internet) – Border routers • Between organization and the Internet• Routing algorithms – Programs on router computers • Determine best path for packetElectronic Commerce, Eighth Edition 23
  24. 24. Routing Packets (cont’d.)• Routing algorithms applied to routing table information• Routing tables (configuration tables) – Contain lists of connections – Contain rules that: • Specify connection to use first • Handle heavy packet traffic and network congestion• Variety rules and standards for creating packets – Must translate packets into standard format • Routers perform translation functionElectronic Commerce, Eighth Edition 24
  25. 25. • Internet backbone – Internet routers handle packet traffic along main connecting points (backbone routers) • Three billion packets per secondElectronic Commerce, Eighth Edition 25
  26. 26. Internet Protocols• ARPANET: Network Control Protocol (NCP)• Protocol: collection of network data rules – Includes transmission rules – Computers must use same protocol• Proprietary architecture (closed architecture) – Manufacturer creates own protocol• Open architecture (Internet core) – Uses common protocol – Four key message-handling rules – Contributed to the Internet’s successElectronic Commerce, Eighth Edition 26
  27. 27. TCP/IP• Internet protocols – Transmission Control Protocol (TCP) • Controls message, file disassembly into packets before Internet transmission • Controls packet reassembly into original formats at destinations – Internet Protocol (IP) • Specifies addressing details for each packet • Labels packet with origination and destination addresses• TCP/IP refers to both protocols – Used today (replaced ARPANET NCP)Electronic Commerce, Eighth Edition 27
  28. 28. IP Addressing• Internet Protocol version 4 (IPv4) – Used for past 20 years• IP address – 32-bit number identifying computers• Base 2 (binary) number system – Computers use for internal calculations – Digit: 0 or a 1 (on or off condition)• Byte (8-bit number) – Octet (networking applications) • Binary values: 00000000 to 11111111 • Decimal equivalents: 0 to 255Electronic Commerce, Eighth Edition 28
  29. 29. IP Addressing (cont’d.)• Dotted decimal notation – IP numbers (addresses) • Four numbers separated by periods • Four parts range from 0 to 255 – IP addresses range: 0.0.0.0 to 255.255.255.255• Three organizations assign IP addresses• Whois server – Returns IP address list owned by an organizationElectronic Commerce, Eighth Edition 29
  30. 30. IP Addressing (cont’d.)• High demand for IP addresses• Subnetting – Use reserved private IP LAN (WAN) addresses • Provide additional address space• Private IP addresses – IP numbers not permitted on Internet packets• Network Address Translation (NAT) device – Converts private IP addresses into normal IP addressesElectronic Commerce, Eighth Edition 30
  31. 31. IP Addressing (cont’d.)• Internet Protocol version 6 (IPv6) – Replace IPv4 (future) • Not directly compatible – Advantages • 128-bit number for addresses • (228): 34 followed by 37 zeros • Packet format change eliminates unnecessary fields • Adds fields for security, other optional information – Shorthand notation system for expressing addresses (complex eight groups of 16 bits) • Group expressed as four hexadecimal digits separated by colonsElectronic Commerce, Eighth Edition 31
  32. 32. Domain Names• Dotted decimal notation difficult to remember• Domain names – Sets of words assigned to specific IP addresses – Example: www.sandiego.edu • Contains three parts separated by periods • Top-level domain (TLD): rightmost part • Generic top-level domains (gTLDs) • Sponsored top-level domains (sTLD) – Internet Corporation for Assigned Names and Numbers (ICANN) • Responsibility: managing non-sTLDElectronic Commerce, Eighth Edition 32
  33. 33. Electronic Commerce, Eighth Edition 33
  34. 34. Web Page Request and Delivery Protocols• Web client computers – Web client software (Web browser software) • Sends Web page file requests to other computers (Web servers)• Web server computer – Web server software • Receives requests from many different Web clients• Client/server architecture – Combination: client computers, server computersElectronic Commerce, Eighth Edition 34
  35. 35. Web Page Request and Delivery Protocols (cont’d.)• Hypertext Transfer Protocol (HTTP) – Internet Web page file delivery rules• Web page request using Web browser – Type of protocol name followed by “//:” before domain name – Uniform Resource Locator (URL) • Combination: protocol name, domain name • Locate resource (Web page) on another computer (Web server)Electronic Commerce, Eighth Edition 35
  36. 36. Electronic Mail Protocols• Electronic mail (e-mail) – Formatted according to common set of rules – Client/server structure• E-mail server – Computer devoted to e-mail handling – Stores, forwards e-mail messages• E-mail client software – Read and send e-mail – Communicates with e-mail server software• Standardization and rules very importantElectronic Commerce, Eighth Edition 36
  37. 37. Electronic Mail Protocols (cont’d.)• Two common protocols – Simple Mail Transfer Protocol (SMTP) • Specifies mail message format • Describes mail administration e-mail server • Describes mail transmission on the Internet – Post Office Protocol (POP) • Sends mail to user’s computer, deletes from server • Sends mail to user’s computer, does not delete • Asks if new mail arrivedElectronic Commerce, Eighth Edition 37
  38. 38. Electronic Mail Protocols (cont’d.)• Multipurpose Internet Mail Extensions (MIME) – Set of rules for handling binary files• Interactive Mail Access Protocol (IMAP) – Newer e-mail protocol • Same basic POP functions • Includes additional featuresElectronic Commerce, Eighth Edition 38
  39. 39. Unsolicited Commercial E-Mail (UCE, Spam)• Spam – Unsolicited commercial e-mail (UCE) – Bulk mail – Electronic junk mail • Wastes people’s time and computer disk space • Consumes large amounts of Internet capacity • Distracts employeesElectronic Commerce, Eighth Edition 39
  40. 40. Markup Languages and the Web• Text markup language – Specifies tag set inserted into text• Markup tags (tags) – Formatting instructions Web client understands• HTML – Web markup language • Most commonly used – Standard Generalized Markup Language (SGML) subset • Older, more complex text markup language • Meta language: used to define other languagesElectronic Commerce, Eighth Edition 40
  41. 41. Markup Languages and the Web (cont’d.)• Extensible Markup Language (XML) – Derived from SGML – Mark up shared information – Meta language • Creates markup elements extending XML usefulness• World Wide Web Consortium (W3C) – Maintains Web standards• Extensible Hypertext Markup Language (XHTML) – HTML version 4.0 reformulation as XML applicationElectronic Commerce, Eighth Edition 41
  42. 42. Electronic Commerce, Eighth Edition 42
  43. 43. Standard Generalized Markup Language• Generalized Markup Language (GML) – Creates standard electronic document formatting styles• International Organization for Standardization (ISO) – Adopted version of GML (SGML) • System of marking up documents • Software application independent • Nonproprietary, platform independent • Offers user-defined tags • Not suited to rapid Web page developmentElectronic Commerce, Eighth Edition 43
  44. 44. Hypertext Markup Language• Hypertext elements – Text elements related to each other• HTML – Prevalent markup language to create Web documents – W3C HTML Working Group page • Detailed HTML versions, related topic information• HTML extensions – Features that work in specific Web browsersElectronic Commerce, Eighth Edition 44
  45. 45. Hypertext Markup Language (cont’d.)• HTML tags – Interpreted by Web browser – Format text display – Enclosed in angle brackets (<>)• Opening tag and closing tag – Format text between them• Closing tag – Preceded by slash within angle brackets (</>)• User may customize tag interpretations• Tags: lowercase or uppercase lettersElectronic Commerce, Eighth Edition 45
  46. 46. Hypertext Markup Language (cont’d.)• One-sided tags – Require opening tag only• Two-sided tags – Optional closing tag – Closing tag position very important• Opening tag may contain one or more property modifiers – Further refine tag operation• Other frequently used HTML tags – Graphics and tablesElectronic Commerce, Eighth Edition 46
  47. 47. Electronic Commerce, Eighth Edition 47
  48. 48. Electronic Commerce, Eighth Edition 48
  49. 49. Hypertext Markup Language (cont’d.)• HTML links – Hyperlinks form interlinked pages that form a “web”• Linear hyperlink structure – Read Web page in serial fashion – Good for when customer fills out form• Hierarchical hyperlink structure – Introductory page (home page, start page) links to other pages – Leads customers from general to specific topics• Hybrid designs combine linear and hierarchical structuresElectronic Commerce, Eighth Edition 49
  50. 50. Electronic Commerce, Eighth Edition 50
  51. 51. Electronic Commerce, Eighth Edition 51
  52. 52. Hypertext Markup Language (cont’d.)• Scripting languages and style sheets• HTML version released (after 1997) – Object tag • Embeds scripting language code on HTML pages • Client-side scripting – Cascading Style Sheets (CSS) • More control over displayed page format – Style sheet • Instructions stored in separate file • Referenced using HTML style tag • May be included in Web page’s HTML fileElectronic Commerce, Eighth Edition 52
  53. 53. Extensible Markup Language (XML)• Web design tool – Web pages contain large amounts of data, lists• Includes data-management capabilities – HTML cannot provide• See Figures 2-10 and 2-11 – Illustrate HTML shortcomings in presenting lists• XML different from HTML – XML is not a markup language with defined tags – XML tags do not specify text appearance on pageElectronic Commerce, Eighth Edition 53
  54. 54. Electronic Commerce, Eighth Edition 54
  55. 55. Electronic Commerce, Eighth Edition 55
  56. 56. • Figures 2-12 and 2-13 – Advantages of XML list presentation • More effectively communicate the meaning of dataElectronic Commerce, Eighth Edition 56
  57. 57. Electronic Commerce, Eighth Edition 57
  58. 58. Extensible Markup Language (XML) (cont’d.)• Strength of XML – Allows users to define their own tags (weakness as well)• Solution to user tag definitions – Common XML tags standards • Data-type definitions (DTDs) or XML schemas – 2001: W3C released set of rules for XML documents• XML files not intended to display in browser – Extensible Stylesheet Language (XSL) • Contains formatting instructions – XML parsers: format XML file for device screenElectronic Commerce, Eighth Edition 58
  59. 59. Electronic Commerce, Eighth Edition 59
  60. 60. HTML and XML Editors• HTML document creation – General-purpose text editor or word processor – Special-purpose HTML editors • Freeware, shareware, commercial – Web site design tools • Create and manage complete Web sites • Upload entire site from PC to Web server • Example: Adobe Dreamweaver• XML files – Created with text editor or programsElectronic Commerce, Eighth Edition 60
  61. 61. Intranets and Extranets• internets (small “i”) – Interconnected networks – Do not extend beyond organizational boundaries• Intranet – Interconnected network (or internet) • Uses TCP/IP protocol set • Does not extend beyond creating organization• Extranet – Intranet extended • Includes specific entities outside organization boundariesElectronic Commerce, Eighth Edition 61
  62. 62. Intranets• Distribute internal corporate information – Low-cost, efficient• Client/server model-based – Requests work same way as on the Internet• Web browsers, Internet-based protocols used• Reduces software maintenance, update costs – Employees’ computer workstations • Script used to update workstations automaticallyElectronic Commerce, Eighth Edition 62
  63. 63. Extranets• Connects company with suppliers, business partners, other authorized users – Database access, files, other information• Set up through the Internet or separate network• Some extranets start as intranets – Select Internet users’ data access – Example: FedEx package-tracking softwareElectronic Commerce, Eighth Edition 63
  64. 64. Public and Private Networks• Public network – Public availability• Private network – Private, leased-line connection – Physically connects intranets to one another• Leased line – Permanent telephone connection between two points – Advantage: security – Drawback: costs • Scaling problem: adding companiesElectronic Commerce, Eighth Edition 64
  65. 65. Virtual Private Network (VPN)• Extranet using public networks and protocols – Sends sensitive data – Uses IP tunneling (encapsulation) system • Private passageway through public Internet • Secure transmission: one computer to another – Encapsulation – Process of creating virtual passageway VPN software • Encrypts packet content, places inside another packet • IP wrapper: outer packet – VPN software installed on both computersElectronic Commerce, Eighth Edition 65
  66. 66. • Leased lines not required• Infrastructure required outside company’s intranet• Extranets sometimes confused with VPNs – VPN is an extranet – Extranet not necessarily a VPNElectronic Commerce, Eighth Edition 66
  67. 67. Internet Connection Options• Internet – Set of interconnected networks• Organizations connect computers using a network• Internet access providers (IAPs) or ISPs – Provide Internet access to: • Individuals, businesses, other organizations – Offer several connection optionsElectronic Commerce, Eighth Edition 67
  68. 68. Connectivity Overview• Common connection options – Voice-grade telephone lines, various types of broadband connections, leased lines, wireless• Distinguishing factor – Bandwidth • Amount of data traveling through communication line per unit of time• Net bandwidth – Actual speed information travels• Symmetric connections – Provide same bandwidth in both directionsElectronic Commerce, Eighth Edition 68
  69. 69. Connectivity Overview (cont’d.)• Asymmetric connections – Provide different bandwidths for each direction• Upstream bandwidth (upload bandwidth) – Amount of information from user to the Internet in a given amount of time• Downstream bandwidth (download, downlink bandwidth) – Amount of information from the Internet to user in a given amount of timeElectronic Commerce, Eighth Edition 69
  70. 70. Voice-Grade Telephone Connections• Local telephone service provider – Most common way for an individual to connect to ISP• Plain old telephone service (POTS) – Uses existing telephone lines, analog modem • Bandwidth between 28 and 56 Kbps• Digital Subscriber Line (DSL) protocol – Higher grade – Use DSL modem• Integrated Services Digital Network (ISDN) – First technology developed using DSL protocol suiteElectronic Commerce, Eighth Edition 70
  71. 71. Broadband Connections• Connection speeds greater than 200 Kbps – Asymmetric digital subscriber line (ADSL) • DSL protocol providing broadband range service – High-speed DSL (HDSL) • More than 768 Kbps symmetric bandwidth – Cable modems • Transmission speeds: 300 Kbps to 1 Mbps • Connection bandwidths vary • Subscribers compete for shared resource – DSL: Private line with no competing traffic• Rural connection option issuesElectronic Commerce, Eighth Edition 71
  72. 72. Leased-Line Connections• More expensive technologies – Classified by equivalent number of telephone lines included• DS0 (digital signal zero) – Carries one digital signal (56 Kbps)• T1 line (DS1) – Carries 24 DS0 lines (1.544 Mbps)• Fractional T1 – 128 Kbps and upward in 128-Kbps increments• T3 (DS3): 44.736 MbpsElectronic Commerce, Eighth Edition 72
  73. 73. Leased-Line Connections (cont’d.)• NAPs and Internet backbone use: – Frame relay – Asynchronous transfer mode (ATM) – Optical fiber (instead of copper wire) • Bandwidth determined by fiber-optic cable class • OC3 (optical carrier 3): 156 Mbps • OC12: 622 Mbps • OC48: 2.5 Gbps • OC192: 10 GbpsElectronic Commerce, Eighth Edition 73
  74. 74. Wireless Connections• Satellite sent microwave transmissions – Download speeds (500 Kbps) – Upload handled by POTS modem connection• Today, companies use microwave transmitter (150 Kbps) – Costs, accuracy improving – POTS modem upload connection not required• Wireless devices – 34 percent of Internet users use wireless devicesElectronic Commerce, Eighth Edition 74
  75. 75. Wireless Connections (cont’d.)• Bluetooth and Ultra Wideband (UWB)• Bluetooth design for use over short distances – Low-bandwidth technology (722 Kbps) – Personal area networks (PANs) or piconets • Small Bluetooth networks – Advantage: consumes very little power• Ultra Wideband (UWB) – 480 Mbps – Connections over short distances (30 to 100 feet) – Future personal area networking applicationsElectronic Commerce, Eighth Edition 75
  76. 76. Wireless Connections (cont’d.)• Wireless Ethernet (Wi-Fi) – Wi-Fi (wireless Ethernet, 802.11b) – Wireless access point (WAP) • Transmits packets between Wi-Fi-equipped computers and other devices within range – 802.11b (11 Mbps): range of about 300 feet – 802.11a (54 Mbps): not 802.11b compatible – 802.11g (54 Mbps): 802.11b compatibleElectronic Commerce, Eighth Edition 76
  77. 77. Wireless Connections (cont’d.)• Wireless Ethernet (Wi-Fi) (cont’d.) – 802.11n: “Draft-N” (300 to 450 Mbps range) • Small office home office (SOHO) market • Finalized specification: 2009 or 2010 – Roaming • Shifting from one WAP to another • No user intervention – Hot spots • WAPs open to publicElectronic Commerce, Eighth Edition 77
  78. 78. Wireless Connections (cont’d.)• Fixed-point wireless – System of repeaters • Forward radio signal from ISP to customers – Repeaters • Transmitter-receiver devices (transceivers) – Uses mesh routing • Directly transmits Wi-Fi packets through short-range transceivers (hundreds or thousands) • Located close to each otherElectronic Commerce, Eighth Edition 78
  79. 79. Wireless Connections (cont’d.)• Cellular telephone networks – Broadcast signals to (receive signals from) antennas • Three miles apart in grid – Original design • Voice communications – Third-generation (3G) cell phones • Combine latest technologies available today – Short message service (SMS) protocol • Send and receive short text messages – Cell phones may include tiny Web browsersElectronic Commerce, Eighth Edition 79
  80. 80. Electronic Commerce, Eighth Edition 80
  81. 81. Internet2 and the Semantic Web• Internet2 – Replacement for original ARPANET laboratory – Experimental networking technologies test bed – High end of the bandwidth spectrum (10 GB) – Universities, medical schools, CERN – Focus • Mainly technology developmentElectronic Commerce, Eighth Edition 81
  82. 82. Internet2 and the Semantic Web (cont’d.)• Semantic Web project (next-generation Web) – Focus • Blending technologies and information – Uses software agents (intelligent programs) • Read XML tags • Determine meaning of words in their contexts – Resource description framework (RDF) • Set of XML syntax standards – Development of Semantic Web will take many years • Start with ontologies for specific subjectsElectronic Commerce, Eighth Edition 82
  83. 83. Summary• In this chapter, you were introduced to: – History of the Internet and Web – Hardware and software technology • Make electronic commerce possible – How the Internet and World Wide Web work – Technologies supporting the Internet, the Web, electronic commerce • Protocols, programs, languages, architectures • TCP/IP • HTML, SGML, XMLElectronic Commerce, Eighth Edition 83
  84. 84. Summary (cont’d.) – Networking technologies • Internets, intranets, and extranets – Types of Internet connections – Internet2 – Semantic Web projectElectronic Commerce, Eighth Edition 84
  1. A particular slide catching your eye?

    Clipping is a handy way to collect important slides you want to go back to later.

×