Title: E-Commerce: The Second Wave Fifth Annual Edition Chapter 2: Technology Infrastructure: The Internet and the World Wide Web
1E-Commerce The Second WaveFifth Annual
Edition Chapter 2Technology Infrastructure
The Internet and the World Wide Web
2Objectives
- 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
3Objectives
- 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
4The 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
5Origins 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
6New 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 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
8Growth of the Internet
9 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
10Emergence 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
11Packet-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
12Packet-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
13Routing 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 Router-based Architecture of the Internet
15Internet 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
16TCP/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
17IP 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
18IP 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
19Domain 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
20Top-level Domain Names
21Web 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
22Web 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)
23Electronic 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
24Electronic 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 users computer and delete it from
e-mail server - Send mail to users computer and not delete it
- Simply ask whether new mail has arrived
- Provides support for Multipurpose Internet Mail
Extensions (MIME)
25Markup 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
26Development of Markup Languages
27 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 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
29Hypertext 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
30Extensible 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 Processing a Request for an XML Page
32Intranets 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
33Public 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
34Virtual 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
35Internet 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
36Voice-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
37Broadband 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
38Leased-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
39Wireless 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
40Wireless 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
41Wireless 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
42Fixed-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
43Cellular 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
44Internet2 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
45Internet2 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
46Summary
- 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)
47Summary
- 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