Technology infrastructure the internet and the world wide web
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Technology Infrastructure: The Internet and the World Wide Web. Electronic Commerce . 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

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Technology infrastructure the internet and the world wide web

Technology Infrastructure: The Internet and the World Wide Web

Electronic Commerce


Objectives

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


Objectives continued

Objectives (continued)

  • 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


The internet and the world wide web

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

Electronic Commerce


Origins of the internet

Origins of the Internet

  • Early 1960s

    • U.S. Department of Defense funded research to explore creating a worldwide network

  • In 1969

    • Defense Department researchers connected four computers into a network called ARPANET

  • Throughout the 1970s and 1980s

    • Academic researchers connected to ARPANET and contributed to its technological developments

Electronic Commerce


New uses for the internet

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 a group of students and programmers at Duke University and the University of North Carolina

Electronic Commerce


Growth of the internet

Growth of the Internet

  • In 1991, the NSF:

    • Eased restrictions on commercial Internet activity

    • Began implementing plans to privatize the Internet

  • Network access points (NAPs)

    • Basis of the new structure of the Internet

  • Network access providers

    • Sell Internet access rights directly to larger customers and indirectly to smaller firms and individuals through ISPs

Electronic Commerce


Chapter 2 slide show

Electronic Commerce


Emergence of the world wide web

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

Electronic Commerce


Emergence of the world wide web continued

Emergence of the World Wide Web (continued)

  • Tim Berners-Lee developed code for a hypertext server program

  • Hypertext server:

    • Stores files written in the hypertext markup language

    • Lets other computers connect to it and read files

  • Hypertext Markup Language (HTML)

    • Includes a set of codes (or tags) attached to text

Electronic Commerce


Packet switched networks

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

Electronic Commerce


Packet switched networks continued

Packet-Switched Networks (continued)

  • Circuit switching

    • Centrally controlled, single-connection model

  • Packets

    • Files and e-mail messages on a packet-switched network are broken down into small pieces, called packets

    • Travel from computer to computer along the interconnected networks until they reach their destinations

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Routing packets

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 packets

    • Programs apply their routing algorithms to information they have stored in routing tables

Electronic Commerce


Chapter 2 slide show

Electronic Commerce


Internet protocols

Internet Protocols

  • Protocol

    • Collection of rules for formatting, ordering, and error-checking data sent across a network

  • Rules for message handling include:

    • 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

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Tcp ip

TCP/IP

  • TCP

    • Controls disassembly of a message or a file into packets before transmission over the Internet

    • Controls reassembly of packets into their original formats when they reach their destinations

  • IP

    • Specifies addressing details for each packet

Electronic Commerce


Ip addressing

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

Electronic Commerce


Ip addressing continued

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

Electronic Commerce


Domain names

Domain Names

  • A domain name is a set of words assigned to a specific IP address

  • 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

Electronic Commerce


Chapter 2 slide show

Electronic Commerce


Web page request and delivery protocols

Web Page Request and Delivery Protocols

  • Web client computers

    • Run software called Web client software or Web browser software

  • Web server computers

    • Run software called Web server software

  • Client/server architecture

    • Combination of client computers running Web client software and server computers running Web server software

Electronic Commerce


Web page request and delivery protocols continued

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 a user to locate a resource (the Web page) on another computer (the Web server)

Electronic Commerce


Electronic mail protocols

Electronic Mail Protocols

  • Electronic mail (e-mail)

    • Must be formatted according to a common set of rules

  • E-mail server

    • Computer devoted to handling e-mail

  • E-mail client software

    • Used to read and send e-mail

    • Examples include Microsoft Outlook and Netscape Messenger

Electronic Commerce


Electronic mail protocols continued

Electronic Mail Protocols (continued)

  • Simple Mail Transfer Protocol (SMTP)

    • Specifies the format of a mail message

  • Post Office Protocol (POP)

    • POP messages can tell the e-mail server to:

      • Send mail to a user’s computer and delete it from the e-mail server

      • Send mail to a user’s computer and not delete it

      • Simply ask whether new mail has arrived

    • POP provides support for Multipurpose Internet Mail Extensions (MIME)

Electronic Commerce


Markup languages and the web

Markup Languages and the Web

  • Text markup language

    • Specifies a set of tags that are inserted into text

  • Standard Generalized Markup Language (SGML)

    • Older and more complex text markup language than HTML

    • A meta language

  • World Wide Web Consortium (W3C)

    • Not-for-profit group that maintains standards for the Web

Electronic Commerce


Chapter 2 slide show

Electronic Commerce


Standard generalized markup language

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

Electronic Commerce


Hypertext markup language html

Hypertext Markup Language (HTML)

  • Prevalent markup language used to create documents on the Web today

  • HTML tags are interpreted by a Web browser and are used by it to format the display of the text

  • HTML links can be structured as:

    • Linear hyperlink structures

    • Hierarchical hyperlink structures

Electronic Commerce


Hypertext markup language html continued

Hypertext Markup Language (HTML) (continued)

  • The most common scripting languages include JavaScript, JScript, Perl, and VBScript

  • Cascading Style Sheets (CSS) are sets of instructions that give Web developers more control over the format of displayed pages

    • Style sheet is:

      • Usually stored in a separate file

      • Referenced using the HTML style tag

Electronic Commerce


Extensible markup language xml

Extensible Markup Language (XML)

  • XML uses paired start and stop tags

  • It 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

Electronic Commerce


Chapter 2 slide show

Electronic Commerce


Intranets and extranets

Intranets and Extranets

  • Intranet

    • Interconnected network that does not extend beyond the organization that created it

  • Extranet

    • Intranet extended to include entities outside the boundaries of an organization

    • Connects companies with suppliers, business partners, or other authorized users

Electronic Commerce


Public and private networks

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

    • Permanent telephone connection between two points

Electronic Commerce


Virtual private network vpn

Virtual Private Network (VPN)

  • VPN

    • An 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

Electronic Commerce


Chapter 2 slide show

Electronic Commerce


Internet connection options

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 the same bandwidth in both directions

  • Asymmetric connections

    • Provide different bandwidths for each direction

Electronic Commerce


Voice grade telephone connections

Voice-Grade Telephone Connections

  • POTS, or plain old telephone service

    • Uses existing telephone lines and an analog modem

    • Provides bandwidth between 28 and 56 Kbps

  • Digital Subscriber Line (DSL)

    • Connection methods that do not use a modem

  • Integrated Services Digital Network (ISDN)

    • Bandwidths between 128 Kbps and 256 Kbps

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Broadband connections

Broadband Connections

  • Broadband connections operate at speeds of greater than 200 Kbps

  • Asymmetric digital subscriber line (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

Electronic Commerce


Leased line connections

Leased-Line Connections

  • DS0 (digital signal zero)

    • Telephone line designed to carry one 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

  • T3service (also called DS3)

    • Offers 44.736 Mbps

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Wireless connections

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

Electronic Commerce


Wireless ethernet wi fi

Wireless Ethernet (Wi-Fi)

  • Wireless Ethernet (Wi-Fi or 802.11b) is the 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 a potential bandwidth of 11 Mbps and a range of about 300 feet

  • Devices are capable of roaming

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Wireless ethernet wi fi continued

Wireless Ethernet (Wi-Fi) (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

Electronic Commerce


Fixed point wireless

Fixed-Point Wireless

  • One versionof fixed-point wirelessuses a system of repeaters to forward a radio signal from an ISP to customers

  • Repeaters

    • Transmitter-receiver devices (transceivers)

  • Mesh routing

    • Directly transmits Wi-Fi packets through hundreds, or even thousands, of short-range transceivers

Electronic Commerce


Cellular telephone networks

Cellular Telephone Networks

  • Third-generation (3G) cell phones

    • Combine the 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

Electronic Commerce


Internet2 and the semantic web

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

Electronic Commerce


Internet2 and the semantic web continued

Internet2 and the Semantic Web (continued)

  • Semantic Web

    • Project by Tim Berners-Lee

    • If successful, it 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

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Summary

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)

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Summary continued

Summary (continued)

  • 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

Electronic Commerce


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