1. E-Commerce: The Second Wave Fifth Annual Edition Chapter 2: Technology Infrastructure: The Internet and the World Wide Web

2. E-Commerce: The Second Wave, Fifth Annual Edition2 Objectives In 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 XML

3. E-Commerce: The Second Wave, Fifth Annual Edition3 Objectives 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 About Internet2 and the Semantic Web

4. E-Commerce: The Second Wave, Fifth Annual Edition4 The Internet and the World Wide Web Computer network –Any technology that allows people to connect computers to each other The Internet –A large system of interconnected computer networks spanning the globe World Wide Web –A subset of computers on the Internet

5. E-Commerce: The Second Wave, Fifth Annual Edition5 Origins of the Internet Early 1960s –U.S. Department of Defense funded research to explore creating a worldwide network In1969, Defense Department researchers –Connected four computers into network called ARPANET Throughout 1970s and 1980s –Academic researchers connected to ARPANET and contributed to its technological developments

6. E-Commerce: The Second Wave, Fifth Annual Edition6 New Uses for the Internet 1972 –E-mail was born Mailing list –E-mail address that forwards any message received to any user who has subscribed to the list Usenet –Started by group of students and programmers at Duke University and the University of North Carolina

7. E-Commerce: The Second Wave, Fifth Annual Edition7 Growth of the Internet In 1991, NSF –Eased restrictions on commercial Internet activity –Began implementing plans to privatize the Internet Network access points (NAPs) –Basis of new structure Internet Network access providers –Sell Internet access rights directly to larger customers and indirectly to smaller firms and individuals through ISPs

8. E-Commerce: The Second Wave, Fifth Annual Edition8 Growth of the Internet

9. E-Commerce: The Second Wave, Fifth Annual Edition9 Emergence of the World Wide Web The Web –Software that runs on computers connected to the Internet Vannevar Bush –Speculated that engineers would eventually build a memory extension device (the Memex) In the 1960s –Ted Nelson described a similar system called hypertext

10. E-Commerce: The Second Wave, Fifth Annual Edition10 Emergence of the World Wide Web (Continued) Tim Berners-Lee –Developed code for hypertext server program Hypertext server –Stores files written in hypertext markup language –Lets other computers connect to it and read files Hypertext Markup Language (HTML) –Includes set of codes (or tags) attached to text

11. E-Commerce: The Second Wave, Fifth Annual Edition11 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

12. E-Commerce: The Second Wave, Fifth Annual Edition12 Packet-Switched Networks (Continued) Circuit switching –Centrally controlled, single-connection model Packets –Files and e-mail messages on a packet- switched network that are broken down into small pieces –Travel from computer to computer along the interconnected networks until they reach their destinations

13. E-Commerce: The Second Wave, Fifth Annual Edition13 Routing Packets Routing computers –Computers that decide how best to forward packets Routing algorithms –Rules contained in programs on router computers that determine the best path on which to send packet –Programs apply their routing algorithms to information they have stored in routing tables

14. E-Commerce: The Second Wave, Fifth Annual Edition14 Router-based Architecture of the Internet

15. E-Commerce: The Second Wave, Fifth Annual Edition15 Internet Protocols Protocol –Collection of rules for formatting, ordering, and error-checking data sent across a network Rules contributing to success of Internet –Independent networks should not require any internal changes to be connected to the network –Packets that do not arrive at their destinations must be retransmitted from their source network –Router computers act as receive-and-forward devices –No global control exists over the network

16. E-Commerce: The Second Wave, Fifth Annual Edition16 TCP/IP TCP –Controls disassembly of a message or a file into packets before transmission over Internet –Controls reassembly of packets into their original formats when they reach their destinations IP –Specifies addressing details for each packet

17. E-Commerce: The Second Wave, Fifth Annual Edition17 IP Addressing Internet Protocol version 4 (IPv4) –Uses a 32-bit number to identify computers connected to the Internet Base 2 (binary) number system –Used by computers to perform internal calculations Subnetting –Use of reserved private IP addresses within LANs and WANs to provide additional address space

18. E-Commerce: The Second Wave, Fifth Annual Edition18 IP Addressing (Continued) Private IP addresses –Series of IP numbers not permitted on packets that travel on the Internet Network Address Translation (NAT) device –Used in subnetting to convert private IP addresses into normal IP addresses Internet Protocol version 6 (IPv6) –Protocol that will replace IPv4 –Uses a 128-bit number for addresses

19. E-Commerce: The Second Wave, Fifth Annual Edition19 Domain Names Sets of words assigned to specific IP addresses Top-level domain (or TLD) –Rightmost part of a domain name Internet Corporation for Assigned Names and Numbers (ICANN) –Responsible for managing domain names and coordinating them with IP address registrars

20. E-Commerce: The Second Wave, Fifth Annual Edition20 Top-level Domain Names

21. E-Commerce: The Second Wave, Fifth Annual Edition21 Web Page Request and Delivery Protocols Web client computers –Run software called Web client software or Web browser software Web server computer –Runs software called Web server software Client/server architecture –Combination of client computers running Web client software and server computers running Web server software

22. E-Commerce: The Second Wave, Fifth Annual Edition22 Web Page Request and Delivery Protocols (Continued) Hypertext Transfer Protocol (HTTP) –Set of rules for delivering Web page files over the Internet Uniform Resource Locator (URL) –Combination of the protocol name and domain name –Allows user to locate a resource (the Web page) on another computer (the Web server)

23. E-Commerce: The Second Wave, Fifth Annual Edition23 Electronic Mail Protocols Electronic mail (e-mail) –Must also be formatted according to common set of rules E-mail server –Computer devoted to handling e-mail E-mail client software –Used to read and send e-mail –Example: Microsoft Outlook, Netscape Messenger

24. E-Commerce: The Second Wave, Fifth Annual Edition24 Electronic Mail Protocols (Continued) Simple Mail Transfer Protocol (SMTP) –Specifies format of a mail message Post Office Protocol (POP) –POP message can tell the e-mail server to Send mail to user’s computer and delete it from e-mail server Send mail to user’s computer and not delete it Simply ask whether new mail has arrived –Provides support for Multipurpose Internet Mail Extensions (MIME)

25. E-Commerce: The Second Wave, Fifth Annual Edition25 Markup Languages and the Web Text markup language –Specifies set of tags that are inserted into text Standard Generalized Markup Language (SGML) –Older and complex text markup language –A meta language World Wide Web Consortium (W3C) –Not-for-profit group that maintains standards for the Web

26. E-Commerce: The Second Wave, Fifth Annual Edition26 Development of Markup Languages

27. E-Commerce: The Second Wave, Fifth Annual Edition27 Standard Generalized Markup Language Offers a system of marking up documents that is independent of any software application Nonproprietary and platform independent Offers user-defined tags Costly to set up and maintain

28. E-Commerce: The Second Wave, Fifth Annual Edition28 Hypertext Markup Language (HTML) Prevalent markup language used to create documents on the Web today HTML tags –Interpreted by Web browser and used by it to format the display of the text HTML Links –Linear hyperlink structure –Hierarchical hyperlink structure

29. E-Commerce: The Second Wave, Fifth Annual Edition29 Hypertext Markup Language (HTML) (Continued) Scripting languages and style sheets –Most common scripting languages JavaScript, JScript, Perl, and VBScript –Cascading Style Sheets (CSS) Sets of instructions that give Web developers more control over the format of displayed pages Style sheet –Usually stored in a separate file –Referenced using the HTML style tag

30. E-Commerce: The Second Wave, Fifth Annual Edition30 Extensible Markup Language (XML) Uses paired start and stop tags Includes data management capabilities that HTML cannot provide Differences between XML and HTML –XML is not a markup language with defined tags –XML tags do not specify how text appears on a Web page

31. E-Commerce: The Second Wave, Fifth Annual Edition31 Processing a Request for an XML Page

32. E-Commerce: The Second Wave, Fifth Annual Edition32 Intranets and Extranets Intranet –Interconnected network that does not extend beyond organization that created it Extranet –Intranet extended to include entities outside boundaries of organization –Connects companies with suppliers, business partners, or other authorized users

33. E-Commerce: The Second Wave, Fifth Annual Edition33 Public and Private Networks Public network –Any computer network or telecommunications network available to the public Private network –A private, leased-line connection between two companies that physically connects their intranets Leased line –A permanent telephone connection between two points

34. E-Commerce: The Second Wave, Fifth Annual Edition34 Virtual Private Network (VPN) Extranet that uses public networks and their protocols IP tunneling –Effectively creates a private passageway through the public Internet Encapsulation –Process used by VPN software VPN software –Must be installed on the computers at both ends of the transmission

35. E-Commerce: The Second Wave, Fifth Annual Edition35 Internet Connection Options Bandwidth –Amount of data that can travel through a communication line per unit of time Net bandwidth –Actual speed that information travels Symmetric connections –Provide same bandwidth in both directions Asymmetric connections –Provide different bandwidths for each direction

36. E-Commerce: The Second Wave, Fifth Annual Edition36 Voice-Grade Telephone Connections POTS, or plain old telephone service –Uses existing telephone lines and analog modem –Provide bandwidth between 28 and 56 Kbps Digital Subscriber Line (DSL) –Connection methods do not use modem Integrated Services Digital Network (ISDN) –Offers bandwidths between 128 Kbps and 256 Kbps

37. E-Commerce: The Second Wave, Fifth Annual Edition37 Broadband Connections Operate at speeds of greater than 200 Kbps Asymmetric digital subscriber (ADSL) –Transmission bandwidth is from 100 to 640 Kbps upstream and from 1.5 to 9 Mbps downstream Cable modems –Provide transmission speeds between 300 Kbps and 1 Mbps DSL –Private line with no competing traffic

38. E-Commerce: The Second Wave, Fifth Annual Edition38 Leased-Line Connections DS0 (digital signal zero) –Telephone line designed to carry 1 digital signal T1 line (also called a DS1) –Carries 24 DS0 lines and operates at 1.544 Mbps Fractional T1 –Provides service speeds of 128 Kbps and upward in 128-Kbps increments T3 service (also called DS3) –Offers 44.736 Mbps

39. E-Commerce: The Second Wave, Fifth Annual Edition39 Wireless Connections Bluetooth –Designed for personal use over short distances –Low-bandwidth technology, with speeds of up to 722 Kbps –Networks are called personal area networks (PANs) or piconets –Consumes very little power –Devices can discover each other and exchange information automatically

40. E-Commerce: The Second Wave, Fifth Annual Edition40 Wireless Ethernet (Wi-Fi or 802.11b) Most common wireless connection technology for use on LANs Wireless access point (WAP) –Device that transmits network packets between Wi-Fi-equipped computers and other devices Has potential bandwidth of 11 Mbps and range of about 300 feet Devices are capable of roaming

41. E-Commerce: The Second Wave, Fifth Annual Edition41 Wireless Ethernet (Wi-Fi or 802.11b) (Continued) 802.11a protocol –Capable of transmitting data at speeds up to 54 Mbps 802.11g protocol –Has 54 Mbps speed of 802.11a –Compatible with 802.11b devices 802.11n –Expected to offer speeds up to 320 Mbps

42. E-Commerce: The Second Wave, Fifth Annual Edition42 Fixed-Point Wireless One version uses system of repeaters to forward radio signal from ISP to customers Repeaters –Transmitter-receiver devices (transceivers) Mesh Routing –Directly transmits Wi-Fi packets through hundreds, or even thousands, of short-range transceivers

43. E-Commerce: The Second Wave, Fifth Annual Edition43 Cellular Telephone Networks Third-generation (3G) cell phones –Combine latest technologies available today Short message service (SMS) –Protocol used to send and receive short text messages Mobile commerce (m-commerce) –Describes the kinds of resources people might want to access using wireless devices

44. E-Commerce: The Second Wave, Fifth Annual Edition44 Internet2 and the Semantic Web Internet2 –Experimental test bed for new networking technologies –Has achieved bandwidths of 10 Gbps and more on parts of its network –Used by universities to conduct large collaborative research projects

45. E-Commerce: The Second Wave, Fifth Annual Edition45 Internet2 and the Semantic Web (Continued) Semantic Web –Project by Tim Berners-Lee – If successful Would result in words on Web pages being tagged (using XML) with their meanings Resource description framework (RDF) –Set of standards for XML syntax Ontology –Set of standards that defines relationships among RDF standards and specific XML tags

46. E-Commerce: The Second Wave, Fifth Annual Edition46 Summary TCP/IP –Protocol suite used to create and transport information packets across the Internet POP, SMTP, and IMAP –Protocols that help manage e-mail Languages derived from SGML –Hypertext Markup Language (HTML) –Extensible Markup Language (XML)

47. E-Commerce: The Second Wave, Fifth Annual Edition47 Summary Intranets –Private internal networks Extranet –Used when companies want to collaborate with suppliers, partners, or customers Internet2 –Experimental network built by a consortium of research universities and businesses