The Internet and the Web:

1
Chapter 2

• The Internet and the Web
• Infrastructure for
• Electronic Commerce

Electronic Commerce
2
Technology Overview

• Internet is the most obvious technology needed to
  conduct e-commerce
• Other technologies are also required
• Database software
• Network switches and hubs
• Encryption hardware and software
• Multimedia support
• Potential for business volume to double in less
  than a year

3
Objectives

• General structure of the network of networks
  supporting the Internet and e-commerce
• Protocols that move commerce across the Internet
  and send/receive e-mail
• Internet utility programs to trace, locate, and
  verify the status of Internet host sites

4
Objectives

• Popular Internet applications, including e-mail,
  Telnet, and FTP
• History and use of Web markup languages,
  including SGML, HTML, and XML
• HTML tags and links
• Web client and server architectures and the
  messages they send to each other

5
Objectives

• Differences and similarities between internets,
  intranets, and extranets
• Options for connecting to the Internet, their
  cost and bandwidth tradeoffs

6
Web Clients and Servers

• Client computers typically request services,
  including printing, information retrieval, and
  database access
• Servers are responsible for processing the
  clients requests

7
Client/Server Structure of the WWW Figure 2-16
8
Web Client/Server Communication

• Two-Tier Client/Server
• All communication takes place between the client
  on the Internet and the target server at the
  other end
• Request message consists of
• A request line
• Optional request headers
• An optional entity body

9
Message Flow Between a Web Client and Server
Figure 2-17
10
Server Response Message Figure 2-18
11
Web Client/Server CommunicationFigure 2-19

• Three-Tiered Client/Server
• First tier is the client
• Second tier is the Web server
• Third tier are the applications and their
  databases
• (Figure 2-19)

12
Open Architecture

• Independent networks should not require any
  internal changes in order to be connected to the
  network
• Packets that do not arrive at their destination
  must be retransmitted
• Router computers do not retain information about
  the packets
• No global control exists over the network

13
The TCP/IP Internet Protocol

• Set of protocols developed by Vincent Cerf and
  Robert Kahn
• Transmission Control Protocol (TCP)
• Controls the assembly of a message into smaller
  packets before transmission, and reassembles them
  once received
• Internet Protocol (IP)
• Rules for routing packets from their source to
  their destination
• Replaced NCP as used by ARPANET

14
TCP/IP Architecture Figure 2-2
15
IP Address and Domain Names

• Appears as a series of up to four separate
  numbers delineated by a period, often referred to
  as a Dotted Quad
• Each of the numbers range from 0 to 255
• First four numbers identify the network
• Following numbers identify a node
• Sample IP address 126.204.89.56

16
IP Address and Domain Names

• Uniform Resource Locator (URL)
• Easier to remember than IP address
• Consists of names and abbreviations
• Contains at least two parts
• First part contains the protocol used
• Second part contains the location of the resource
• http//www.adobe.com

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Top-Level Domain Names Figure 2-3
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Other Internet Protocols

• Hypertext Transfer Protocol (HTTP)
• Responsible for transferring and displaying Web
  pages
• Simple Mail Transfer Protocol (SMTP)
• Specifies the exact format of a mail message
• Post Office Protocol (POP)
• Responsible for retrieving e-mail from a mail
  server

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Other Internet Protocols

• Interactive Mail Access Protocol (IMAP)
• Latest protocol, may replace POP
• Defines how a client program asks a mail server
  to present available mail
• Download only selected messages, instead of all
  messages
• View headers only
• Create and manipulate mailboxes on the server

20
Other Internet Protocols

• File Transfer Protocol (FTP)
• Transfers files between TCP/IP-connected
  computers
• Uses client/server model
• Transfers both binary and ASCII text
• Displays and manipulates remote and local
  computer file directories

21
Internet Utility Programs

• Finger
• Runs on UNIX computers and allows users to obtain
  limited information about other network users

22
Finger Program Output Figure 2-4
23
Internet Utility Programs

• Packet InterNet Groper (Ping)
• Tests the connectivity between two Internet hosts
• Determines if the host is active
• Sends a packet and waits for a reply
• Determines number of hosts (hops) between two
  specified hosts

24
Tracert and Other Route-Tracing Programs

• TRACE RouTe (Tracert) traces the round trip path
  between a users computer and another computer on
  the Internet
• Incorporates a Graphical User Interface (GUI) for
  a visual representation of the route

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Tracing a Path Between Two Computers Figure 2-5
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Internet Applications Electronic Mail

• Began in the 1970s for use on the ARPANET
• Most popular form of business communication
• Can send documents, pictures, movies, worksheets,
  or other important pieces of information

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Sending E-Mail Attachments Figure 2-6
28
Internet Applications Telnet

• Allows users to log on to a remote computer that
  is attached to the Internet
• Type commands to run on the remote host computer
  by using terminal emulation
• Client software is available, and users can
  access Telnet through most Web browsers

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Example of a Telnet Session Figure 2-7
30
Internet Applications FTP

• Fastest way to deliver digital business
  information from one computer to another
• Commonly used to download software packages and
  updates
• Also used to upload files to the host computer
  for access from the Internet

31
An FTP Session Figure 2-8
32
Markup Languages and the Web

• Standard Generalized Markup Language (SGML)
• Regulated ISO standard since 1986
• Nonproprietary
• Supports user-defined tags
• Costly to set up
• Expensive compared to HTML
• Steep learning curve

33
Markup Languages and the Web

• Hypertext Markup Language (HTML)
• Based on SGML
• Easier to learn and support
• Supports commonly used text markup features
• Headings, title bars, bullets, lines, lists
• Precise graphic positioning, tables, and frames
• Standard language for Web pages

34
Markup Languages and the Web

• Extensible Markup Language (XML)
• Descendant of SGML
• Defines which data to display, instead of how a
  page is displayed
• Describes a pages actual content, unlike HTML
• Data-tracking capability

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XML Example Figure 2-9
36
Traditional vs. Hyperlinked Document Pages Figure
2-10
37
More about HTML

• HTML tags
• lttagname propertiesgtDisplayed information
  affected by taglt/tagnamegt
• ltBgtbestlt/Bgt - Bolds the word best
• ltP alignrightgt - Aligns text to the right
• HTML code defines the formatting of the page, but
  a page may look different on two different
  browsers

38
Web Page and Paragraph Tag With Right-Align
Property Figure 2-11
39
HTML Codes to Format Memo Page Figure 2-12
40
Internet Explorer Display of Memo Page Figure 2-13
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More about HTML

• HTML Links
• Anchor tags used to link to text within the same
  document, or on a distant computer
• ltA HREFaddressgtVisible link textlt/Agt
• ltA HREFhttp//www.purdue.edugtPurdue
  Universitylt/Agt
• ltA HREFreferencesgtReferences are found
  herelt/Agt
• Text between the anchors appears as a hyperlink

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Hyperlink StructuresFigure 2-14
43
HTML Version History

• Version 1.0 appeared in the summer of 1991
• Version 2.0 was released in September 1995
• Internet Explorer 2.0 and Netscape Navigator 2.0
  appeared
• Version 3.2 was released in 1997
• Provided support for tables, complex numbers, and
  text flow around images

44
HTML Version History

• Version 4.0 was released in December 1997
• Support for OBJECT tag and Cascading Style Sheets
  (CSS)
• Internationalization for various languages
• Accessibility features

45
HTML Editors

• Used to generate the HTML code
• Simple text editors offer limited flexibility
• Any word processor can be used
• Web site builders offer more control
• Microsoft FrontPage
• Dreamweaver

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Dreamweaver Site Builder Software Figure 2-15
47
Networks

• Local and long distance telephone companies were
  early models in the 1950s
• Single paths were created to connect two parties
  together, called circuit switching

48
Packet-Switched Networks

• The Internet uses Packet switching
• Files and messages are broken down into packets,
  which are electronically labeled with their
  origin and destination
• The destination computer collects the packets and
  reassembles the data from the pieces in each
  packet
• Each computer the packet encounters decides the
  best route towards its destination

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Packet-Switched Network and Message
Packets Figure 2-1
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Internets, Intranets, and Extranets

• Intranets
• Only selected individuals are allowed access
• Low-cost way to distribute corporate information
• Collect and group information for external
  dissemination
• Infrastructure requirements are usually in place
  if PCs are on a LAN

51
Internets, Intranets, and Extranets

• Extranets
• Connect companies with suppliers or other
  business partners
• Provide the infrastructure for the coordination
  of purchases, EDI, and communications
• Use the Internet for communicating among
  themselves

52
FedEx Ship Page Figure 2-20
53
Internets, Intranets, and Extranets

• Public Network
• An extranet that allows the public to access its
  intranet
• When two or more companies agree to link their
  intranets using a public network (such as the
  Internet)
• Private Network
• A leased-line connection that physically connects
  two intranets

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Internets, Intranets, and Extranets

• Virtual Private Network (VPN)
• Uses public networks and protocols to send
  sensitive data by using tunneling or
  encapsulation - private passageways through the
  Internet
• Designed to save money and create a competitive
  advantage by alliances formed with cooperating
  companies

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Secure VPN Extranet Figure 2-21
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Internet Connections Options and Tradeoffs

• Internet Service Providers (ISPs) offer
  connection choices to their users
• Plain Old Telephone Service (POTS)
• Existing telephone lines with modems
• Bandwidth of 56Kbps (56,000 bits per second)
• Integrated Services Digital Network (ISDN)
• Bandwidths up to 128Kbps
• Asymmetric Digital Subscriber Line (ADSL)
• Upload at 640Kbps, download up to 9Mbps

57
Cable Modems

• Same broadband coaxial cable that serves cable
  television
• Upstream bandwidths of 300-500 Kbps
• Downstream bandwidths of 1.5Mbps

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Internet Connection Choices Figure 2-22