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Electronic Commerce Eighth Edition. Chapter 2 Technology Infrastructure: The Internet and the World Wide Web. Learning 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 - PowerPoint PPT Presentation
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Electronic CommerceEighth Edition
Chapter 2Technology Infrastructure: The Internet
and the World Wide Web
Electronic Commerce, Eighth Edition 2Electronic Commerce, Eighth Edition 2
Learning 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
Electronic Commerce, Eighth Edition 3Electronic Commerce, Eighth Edition 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 Web
Electronic Commerce, Eighth Edition 4Electronic Commerce, Eighth Edition 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 interfaces
Electronic Commerce, Eighth Edition 5
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 individuals
Electronic Commerce, Eighth Edition 6
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 Web
Electronic Commerce, Eighth Edition 7
Electronic Commerce, Eighth Edition 8
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 interfaces
Electronic Commerce, Eighth Edition 9
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 Web
Electronic Commerce, Eighth Edition 10
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 document
Electronic Commerce, Eighth Edition 11
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 elements
Electronic Commerce, Eighth Edition 12
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 computers
Electronic Commerce, Eighth Edition 13
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 itself
Electronic Commerce, Eighth Edition 14
• Estimates– More than 140 million Web sites– More than 30 billion individual Web pages
• Commercial business Web use increasing
Electronic Commerce, Eighth Edition 15
Networks
• Local area network (LAN)– Network of computers located close together
• Wide area networks (WANs)– Networks of computers connected over greater
distances
Electronic Commerce, Eighth Edition 16
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-sTLD
Electronic Commerce, Eighth Edition 17
Electronic Commerce, Eighth Edition 18
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 computers
Electronic Commerce, Eighth Edition 19
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 20
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 important
Electronic Commerce, Eighth Edition 21
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 arrived
Electronic Commerce, Eighth Edition 22
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 features
Electronic Commerce, Eighth Edition 23
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 employees
Electronic Commerce, Eighth Edition 24
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 browsers
Electronic Commerce, Eighth Edition 25
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 letters
Electronic Commerce, Eighth Edition 26
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 tables
Electronic Commerce, Eighth Edition 27
Electronic Commerce, Eighth Edition 28
Electronic Commerce, Eighth Edition 29
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 boundaries
Electronic Commerce, Eighth Edition 30
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 automatically
Electronic Commerce, Eighth Edition 31
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 software
Electronic Commerce, Eighth Edition 32
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 companies
Electronic Commerce, Eighth Edition 33
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 computers
Electronic Commerce, Eighth Edition 34
• Leased lines not required
• Infrastructure required outside company’s intranet
• Extranets sometimes confused with VPNs– VPN is an extranet– Extranet not necessarily a VPN
Electronic Commerce, Eighth Edition 35
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 options
Electronic Commerce, Eighth Edition 36
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 directions
Electronic Commerce, Eighth Edition 37
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 time
Electronic Commerce, Eighth Edition 38
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 devices
Electronic Commerce, Eighth Edition 39
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 applications
Electronic Commerce, Eighth Edition 40
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 compatible
Electronic Commerce, Eighth Edition 41
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 browsers
Electronic Commerce, Eighth Edition 42
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, XML
Electronic Commerce, Eighth Edition 43
Summary (cont’d.)
– Networking technologies• Internets, intranets, and extranets
– Types of Internet connections– Internet2– Semantic Web project
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