web technologies comp6115 session 1: internetworking and the world wide web dr. paul walcott...

Web Technologies Web Technologies COMP6115COMP6115

Session 1: Internetworking and the World Session 1: Internetworking and the World Wide WebWide Web

Dr. Paul Walcott Dr. Paul Walcott Department of Computer Science, Mathematics and PhysicsDepartment of Computer Science, Mathematics and Physics

University of the West Indies, Cave Hill CampusUniversity of the West Indies, Cave Hill CampusBarbadosBarbados

© 2006/2007 Dr. Paul Walcott

Created 20/11/06

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Session ObjectivesSession Objectives

• After completing this session you will After completing this session you will be able to:be able to:– Briefly describe the Internet and discuss Briefly describe the Internet and discuss

its historyits history– Briefly describe the World Wide Web Briefly describe the World Wide Web

(WWW)(WWW)– Describe some of the software required to Describe some of the software required to

build an e-commerce Web sitebuild an e-commerce Web site– Describe the Open System Describe the Open System

Interconnection (OSI) modelInterconnection (OSI) model

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Session Objectives Cont’dSession Objectives Cont’d

– Describe the use of tools in the Describe the use of tools in the construction of Web sitesconstruction of Web sites

– Compare and contrast different types of Compare and contrast different types of computer networkscomputer networks

– Compare and contrast different methods Compare and contrast different methods of connecting to the Internetof connecting to the Internet

– Create a simple Web PageCreate a simple Web Page

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The InternetThe Internet

• What is What is the the InternetInternet??

• The history of the The history of the InternetInternet

• The growth of the The growth of the InternetInternet

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What is the InternetWhat is the Internet11

• The Internet is a large system of The Internet is a large system of inter-connected networks that span inter-connected networks that span the globethe globe

• Internet-ready computers and Internet-ready computers and personal digital assistants (palm and personal digital assistants (palm and pocket PCs) can access this networkpocket PCs) can access this network22

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What is the Internet Cont’dWhat is the Internet Cont’d

• The Federal Networking Council The Federal Networking Council (FNC)(FNC) defines the Internet more defines the Internet more formally as the global information formally as the global information system thatsystem that33::– is logically linked together by a globally is logically linked together by a globally

unique address space based on the unique address space based on the Internet Protocol (IP) or its subsequent Internet Protocol (IP) or its subsequent extensions/follow-onsextensions/follow-ons

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– is able to support communications using is able to support communications using the Transmission Control Protocol/Internet the Transmission Control Protocol/Internet Protocol (TCP/IP) suite or its subsequent Protocol (TCP/IP) suite or its subsequent extensions/follow-ons, and/or other IP-extensions/follow-ons, and/or other IP-compatible protocols; andcompatible protocols; and

– provides, uses or makes accessible, either provides, uses or makes accessible, either publicly or privately, high level services publicly or privately, high level services layered on the communications and layered on the communications and related infrastructure described hereinrelated infrastructure described herein

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• The Internet allows:The Internet allows:– communication by e-mailcommunication by e-mail– the reading of on-line newspapers, academic the reading of on-line newspapers, academic

journals and booksjournals and books– the joining of discussion groups,the joining of discussion groups,– participation in simulations and gamesparticipation in simulations and games– downloading of software, electronic books, downloading of software, electronic books,

movies and musicmovies and music– businesses to market and sell products and businesses to market and sell products and

services (e-commerce)services (e-commerce)

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The History of the InternetThe History of the Internet11

• In the early 1960s the US department of In the early 1960s the US department of defense began investigating ways of creating defense began investigating ways of creating networks of computers that coordinate and networks of computers that coordinate and control nuclear weaponscontrol nuclear weapons

• This network was to withstand attack, so that This network was to withstand attack, so that even if part of it was down it will continue to even if part of it was down it will continue to functionfunction– This network was to have no central controlThis network was to have no central control

• These new networks required multiple These new networks required multiple channels to send information (leased lines channels to send information (leased lines inadequate)inadequate)

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The History of the Internet The History of the Internet Cont’dCont’d• In 1969 the advanced research In 1969 the advanced research

agency (ARPA) used this network agency (ARPA) used this network model to connect four computersmodel to connect four computers

• This network was called ARPANETThis network was called ARPANET• During the 1970s and 1980s the During the 1970s and 1980s the

academic community contributed to academic community contributed to this networkthis network

• In the late 1980s this network became In the late 1980s this network became the Internetthe Internet

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Internet GrowthInternet Growth11

• In 1969 ARPANET (the Internet) In 1969 ARPANET (the Internet) connected 4 computersconnected 4 computers

• In 1990 the Internet connected 300,000In 1990 the Internet connected 300,000

• In 1995 the intranet was In 1995 the intranet was privatisedprivatised– The structure was based on four network The structure was based on four network

access points (NAPs) operated by different access points (NAPs) operated by different telecom companies in the UStelecom companies in the US

– As the Intranet grew, more NAPs were As the Intranet grew, more NAPs were addedadded

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Internet Growth Cont’dInternet Growth Cont’d

• The NAPs began selling Internet access rights The NAPs began selling Internet access rights to large customersto large customers– Internet service providers (ISPs) sold on the service Internet service providers (ISPs) sold on the service

to small businesses and individualsto small businesses and individuals

• Growth in Internet hosts rose from under 10 Growth in Internet hosts rose from under 10 million in 1995 to over 180 million in 2004million in 1995 to over 180 million in 2004

• Millions of people now use the InternetMillions of people now use the Internet• Billions of dollars are exchanged from the sales Billions of dollars are exchanged from the sales

of products and servicesof products and services• Estimated number of Web sites is 40 million Estimated number of Web sites is 40 million

and billions of web pagesand billions of web pages

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The World Wide WebThe World Wide Web

• What is the World What is the World Wide Web?Wide Web?

• What is hypertext?What is hypertext?

• Hypertext markup Hypertext markup language (HTML) language (HTML) exampleexample

• What types of Web What types of Web sites exist?sites exist?

www.ransen.com/Repligator/Spider.htm

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What is the World Wide WebWhat is the World Wide Web

• The World Wide Web (WWW) was an The World Wide Web (WWW) was an Internet-based hypertext project that Internet-based hypertext project that allowed global information sharingallowed global information sharing22

– It is software that runs on machines It is software that runs on machines connected to the WWWconnected to the WWW

• The WWW is based on two conceptsThe WWW is based on two concepts11::– Hypertext andHypertext and– a graphical user interface (a Web browser)a graphical user interface (a Web browser)

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What is HypertextWhat is Hypertext11

• In 1945, Vannevar Bush wrote an In 1945, Vannevar Bush wrote an article in the Atlantic Monthly article in the Atlantic Monthly describing a system, called Memex, describing a system, called Memex, that would store all a person’s books, that would store all a person’s books, records, letters and research results on records, letters and research results on microfilmmicrofilm

• Microfilm and indexes would then be Microfilm and indexes would then be used to quickly access this informationused to quickly access this information

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What is Hypertext Cont’dWhat is Hypertext Cont’d

• In the 1960s, Ted Nelson described a In the 1960s, Ted Nelson described a similar system:similar system:– He incorporated a page linking system He incorporated a page linking system

called hypertextcalled hypertext

• Tim Berners-Lee wrote a hypertext Tim Berners-Lee wrote a hypertext server in 1989 whichserver in 1989 which

•stored files written in hypertext markup stored files written in hypertext markup language (HTML)language (HTML)

•allowed other computers to read these filesallowed other computers to read these files

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What is Hypertext Cont’dWhat is Hypertext Cont’d

• Tim Berners-Lee hypertext server Tim Berners-Lee hypertext server was called httpd and his client was called httpd and his client browser “WorldWideWeb”browser “WorldWideWeb”

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HyperText Markup HyperText Markup LanguageLanguage• HTML is a markup language that includes HTML is a markup language that includes

a set of tags attached to texta set of tags attached to text• These tags describe the relationship These tags describe the relationship

between text elementsbetween text elements• A hypertext link (or hyperlink) points to A hypertext link (or hyperlink) points to

another location in the same or another another location in the same or another HTML document (that might be stored on HTML document (that might be stored on the same or another computer)the same or another computer)

• Given below is an example of a simple Given below is an example of a simple HTML document. HTML document.

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HTML ExampleHTML Example

<html>  <head> <title>Hypertext Markup Language (HTML) Example</title> </head>  <body bgcolor="#0000AA"> <font color="#FFFFFF"> <h1><u>Hypertext Markup Language</u></h1> Hypertext Markup Language (HTML) allows users to: <ol> <li>format and display text</li> <li>display images </li> <li>and so much more …</li> </ol> <img src="HTMLexample.jpg"> <a href="#top">Go to top of page</a> </font> </body> </html>

Begins the HTML document

HTML docs contain botha head and body section

Sets browser’s background colourto blue and font colour to white

Creates a bulleted list of items

Inserts an image

Creates a hyperlink back to the top of the page

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Activity 1.1Activity 1.1

• Create a simple web page for your Create a simple web page for your curriculum vitaecurriculum vitae

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XML Markup LanguageXML Markup Language

• XML or Extensible Markup Language XML or Extensible Markup Language is a markup language that is similar is a markup language that is similar to HTMLto HTML

• HTML and XML, however have HTML and XML, however have different purposes:different purposes:– HTML is primarily used to present HTML is primarily used to present

(display) data, while(display) data, while– XML is used to describe dataXML is used to describe data

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XML ExampleXML Example

<?xml version="1.0"?><degree> <course name="COMP1130" year="2004-2005"> <test1 maximumMark = "10">8.2</test1> <test2 maximumMark ="10">5.6</test2> <project maximumMark="10">10</project> <lab maximumMark ="10">9</lab> <exam maximumMark = "60">45</exam> </course>

<course name="COMP3210" year="2005-2006"> <test1 maximumMark = "10">9</test1> <test2 maximumMark ="10">9.5</test2> <project maximumMark="10">10</project> <lab maximumMark ="10">10</lab> <exam maximumMark = "60">50</exam> </course></degree>

Begin the XML document byspecifying the XML version

Every XML document musthave a root node

The user defines tag names

A tag can have zero, one ormore attributes

Every opening tag must have a closing tag.

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• Create an XML document with a Create an XML document with a different structure than the XML different structure than the XML document on the previous slide, but document on the previous slide, but with the same datawith the same data

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Graphical Interface for Graphical Interface for HypertextHypertext

• A Web browser is a graphical user interface used to A Web browser is a graphical user interface used to read and navigate through files written in HTMLread and navigate through files written in HTML

• In 1993 the first graphical web browser was In 1993 the first graphical web browser was developed; called Mosiac developed; called Mosiac (http://archive.ncsa.uiuc.edu/SDG/Software/Mosaic/NCSAMosaicHome.html)(http://archive.ncsa.uiuc.edu/SDG/Software/Mosaic/NCSAMosaicHome.html)

• Popular web browsers include:Popular web browsers include:– Microsoft Internet Explorer Microsoft Internet Explorer

(http://www.microsoft.com/windows/ie/default.m(http://www.microsoft.com/windows/ie/default.mspx)spx)

– Netscape (http://browser.netscape.com)Netscape (http://browser.netscape.com)– Mozilla Firefox (http://www.mozilla.com/firefox/)Mozilla Firefox (http://www.mozilla.com/firefox/)

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Mosiac Web BrowserMosiac Web Browser

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Internet Explorer Web Internet Explorer Web BrowserBrowser

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Netscape Web BrowserNetscape Web Browser

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Mozilla Firefox Web BrowserMozilla Firefox Web Browser

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• Using your favourite search engine, Using your favourite search engine, locate, download and install the locate, download and install the following web browsers:following web browsers:– MosiacMosiac– NetscapeNetscape– Mozilla FirefoxMozilla Firefox– OperaOpera

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Hypertext Servers (Web Hypertext Servers (Web Servers)Servers)11

• There are several Web servers available There are several Web servers available today, however the most popular are (April today, however the most popular are (April 2006 survey)2006 survey)4,84,8::– Apache HTTP Server 67.11% (down from Apache HTTP Server 67.11% (down from

69.01% in 2004)69.01% in 2004)– Microsoft Internet Information Server (IIS) Microsoft Internet Information Server (IIS)

20.61% (down from 23.26% in 2004)20.61% (down from 23.26% in 2004)– Sun Java System Web Server (JSWS) (former Sun Java System Web Server (JSWS) (former

names are Sun One, iPlanet Enterprise Server names are Sun One, iPlanet Enterprise Server and Netscape Enterprise Server) 2.50% (up and Netscape Enterprise Server) 2.50% (up from 0.86% in 2004)from 0.86% in 2004)

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ApacheApache (“A Patchy” (“A Patchy” Server)Server)• Developed in 1994 by Rob McCoolDeveloped in 1994 by Rob McCool• The original core system has many The original core system has many

patches applied to it, and thus its namepatches applied to it, and thus its name• Apache has dominated the Web since Apache has dominated the Web since

19961996• Freely availableFreely available• Runs on many operating systems Runs on many operating systems

including FreeBSD-UNIX, HP-UX, Linux, including FreeBSD-UNIX, HP-UX, Linux, Microsoft Windows, SCO-UNIX and SolarisMicrosoft Windows, SCO-UNIX and Solaris

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Microsoft Internet Microsoft Internet Information Server (IIS)Information Server (IIS)• Comes bundled with Microsoft Windows Comes bundled with Microsoft Windows

Server operating systemServer operating system• IIS used on many corporate intranets IIS used on many corporate intranets

(Microsoft standard product)(Microsoft standard product)• Originally written to run on Windows NT Originally written to run on Windows NT

and Windows 2000; runs on Windows 2003 and Windows 2000; runs on Windows 2003 Server and Windows XPServer and Windows XP

• Supports ASP, ActiveX Data objects and Supports ASP, ActiveX Data objects and SQL queriesSQL queries

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Sun Java System Web Sun Java System Web ServerServer• This is a descendant of the original NCSA This is a descendant of the original NCSA

serverserver

• Cost US$1500-per-CPU licensing feeCost US$1500-per-CPU licensing fee

• Runs on HP-UX, Solaris and WindowsRuns on HP-UX, Solaris and Windows

• Is ODBC compatible (i.e. full access to ODBC Is ODBC compatible (i.e. full access to ODBC compliant databases)compliant databases)– ODBC is short for Open DataBase Connectivity, a ODBC is short for Open DataBase Connectivity, a

standard database access method which allows standard database access method which allows access to data from any application access to data from any application (http://www.webopedia.com/TERM/O/ODBC.html)(http://www.webopedia.com/TERM/O/ODBC.html)

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• Using your favourite search engine, Using your favourite search engine, locate, download and install the locate, download and install the Apache Web serverApache Web server

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Web Site TypesWeb Site Types

• There are numerous different types of Web There are numerous different types of Web sites including:sites including:– Development sitesDevelopment sites: are used by companies to : are used by companies to

evaluate web site designs. The initial investment evaluate web site designs. The initial investment in these sites are small since they use existing in these sites are small since they use existing hardware (i.e. no special hardware is purchased)hardware (i.e. no special hardware is purchased)

– IntranetsIntranets: these are corporate networks that : these are corporate networks that hold documents such as internal memos, hold documents such as internal memos, corporate handbooks, expense account corporate handbooks, expense account worksheets, budgets and newslettersworksheets, budgets and newsletters

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Web Site Types Cont’dWeb Site Types Cont’d

– ExtranetsExtranets: which allow external entities, e.g. : which allow external entities, e.g. suppliers and strategic partners to access a suppliers and strategic partners to access a subset of the information on the Intranetsubset of the information on the Intranet

– Transaction-processingTransaction-processing: These sites operate : These sites operate 24 hours a day, seven days a week and require 24 hours a day, seven days a week and require fast, reliable hardware and e-commerce fast, reliable hardware and e-commerce softwaresoftware• Web sites hosting B2B and B2C activities must have Web sites hosting B2B and B2C activities must have

spare capacity to support an increase in customer spare capacity to support an increase in customer volume.volume.

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Web Site Types Cont’dWeb Site Types Cont’d

– Content-deliveryContent-delivery: sites must be : sites must be available seven days a week, 24 hours a available seven days a week, 24 hours a day and require fast and precise search day and require fast and precise search engines to help visitors locate engines to help visitors locate information quicklyinformation quickly•These sites deliver content such as news, These sites deliver content such as news,

histories and other digital information.histories and other digital information.

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NetworkingNetworking

• What is a computer What is a computer network?network?

• What are some of the What are some of the types of networks?types of networks?

• Characteristics of Characteristics of networksnetworks– Network topologyNetwork topology– Network protocolsNetwork protocols– Network architecturesNetwork architectureshttp://www-structure.llnl.gov/Xray/comp/network.gif

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What is a NetworkWhat is a Network55

• A network is a group of two or more A network is a group of two or more computer systems linked togethercomputer systems linked together

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Types of NetworksTypes of Networks66

• There are several types of computer There are several types of computer networks including:networks including:– Local-area networks (LANs)Local-area networks (LANs)

•Computers that are geographically close to Computers that are geographically close to each other (in the same building)each other (in the same building)

– Wide-area networks (WANs)Wide-area networks (WANs)•Computers are farther apart than LANs; Computers are farther apart than LANs;

typically connected by telephone lines or typically connected by telephone lines or radio waves radio waves

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Types of Networks Cont’dTypes of Networks Cont’d

– Campus-area networks (CANs)Campus-area networks (CANs)•These computers are within a limited These computers are within a limited

geographic area, e.g. a campusgeographic area, e.g. a campus

– Metropolitan-area networks (MANs)Metropolitan-area networks (MANs)•These networks are designed for towns and These networks are designed for towns and

citiescities

– Home-area networks (HANs)Home-area networks (HANs)•A network created in a person’s homeA network created in a person’s home

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Characteristics of Characteristics of NetworksNetworks5,65,6

• A network is characterised by its:A network is characterised by its:– TopologyTopology

• The geometric arrangement of the computer systemThe geometric arrangement of the computer system

– ArchitectureArchitecture• This refers to the two major type of networks, peer-This refers to the two major type of networks, peer-

to-peer or client/serverto-peer or client/server

– ProtocolProtocol• The set of rules and signals used to communicate The set of rules and signals used to communicate

(e.g. Ethernet or IBM’s Token Ring)(e.g. Ethernet or IBM’s Token Ring)

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Network TopologiesNetwork Topologies66

• Common network Common network topologies include:topologies include:– Star topologyStar topology– Ring topologyRing topology– Bus topologyBus topology– Other topologies Other topologies

include the:include the:• Mesh topologyMesh topology

• Tree topologyTree topology

http://www.webopedia.com/TERM/s/star_network.html

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Network Topologies Cont’dNetwork Topologies Cont’d

• Network topologies are considered Network topologies are considered either logical or physicaleither logical or physical– The physical layout of a network is its The physical layout of a network is its

physical topologyphysical topology– The way signals are routed through a The way signals are routed through a

network is the logical topologynetwork is the logical topology

• Just because a network has a particular Just because a network has a particular physical topology does not mean that physical topology does not mean that its logical topology must be the sameits logical topology must be the same

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Network Topologies Cont’dNetwork Topologies Cont’d

• For example:For example:– Twisted-pair Ethernet has a logical bus Twisted-pair Ethernet has a logical bus

topology on a physical star topology topology on a physical star topology layoutlayout

– IBM’s token ring has a logical ring IBM’s token ring has a logical ring topology on a physical star topology topology on a physical star topology layoutlayout

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Star TopologyStar Topology

• In a Star network all nodes are In a Star network all nodes are connected through a central hubconnected through a central hub– A node is a computer or device, e.g. a A node is a computer or device, e.g. a

printer; each node has a unique address printer; each node has a unique address called the Data Link Control (DLC) called the Data Link Control (DLC) address or the Media Access Control address or the Media Access Control (MAC) address(MAC) address

• The main advantage of the star The main advantage of the star network is that a malfunctioning node network is that a malfunctioning node does not affect the rest of the networkdoes not affect the rest of the network

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Star Topology Cont’dStar Topology Cont’d

• The main disadvantage of the star The main disadvantage of the star network is that:network is that:– It requires more cabling than other It requires more cabling than other

topologies (e.g. the ring network), andtopologies (e.g. the ring network), and– If the hub goes down, the network no If the hub goes down, the network no

longer functionslonger functions

• Standard twisted-pair Ethernet uses Standard twisted-pair Ethernet uses a physical star topologya physical star topology

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Ring TopologyRing Topology

• Each node in a ring network is connected to Each node in a ring network is connected to two other nodes to form a closed looptwo other nodes to form a closed loop

• Messages pass around the ring and each node Messages pass around the ring and each node reads the message addressed to itreads the message addressed to it

• One advantage of a ring network is that it can One advantage of a ring network is that it can span larger distances than other networks (e.g. span larger distances than other networks (e.g. bus) because each node regenerates the signalbus) because each node regenerates the signal

• One disadvantage is that malfunctioning nodes One disadvantage is that malfunctioning nodes can make other nodes inaccessiblecan make other nodes inaccessible

• IBM’s token ring uses a logical ring topologyIBM’s token ring uses a logical ring topology

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Bus TopologyBus Topology

• The nodes in a bus topology are connected to The nodes in a bus topology are connected to a central cable called a bus or backbonea central cable called a bus or backbone

• The bus has two end pointsThe bus has two end points• One advantage of the bus network is that if One advantage of the bus network is that if

one node goes down the network still functionsone node goes down the network still functions• One disadvantage of the bus network is it can One disadvantage of the bus network is it can

not travel as long a distance as say a ring not travel as long a distance as say a ring network due to the diminishing signal strengthnetwork due to the diminishing signal strength

• Ethernet 10Base-2 and 10Base-5 use the bus Ethernet 10Base-2 and 10Base-5 use the bus topologytopology

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• Using your favourite search engine Using your favourite search engine identify other network topologiesidentify other network topologies

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Mesh TopologyMesh Topology

• In the mesh In the mesh topology many topology many redundant redundant connections exist connections exist between nodes; in between nodes; in a true mesh, each a true mesh, each node is connected node is connected to every other to every other nodenode

http://www.webopedia.com/quick_ref/topologies.asp

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Tree TopologyTree Topology

• The tree topology The tree topology is a hybrid where is a hybrid where groups of star-groups of star-configured configured networks networks are are connected to a connected to a linear bus linear bus backbonebackbone

http://www.webopedia.com/quick_ref/topologies.asp

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ArchitectureArchitecture66

• The two main The two main types of types of architecture arearchitecture are– Peer-to-Peer (P2P)Peer-to-Peer (P2P)– Client/ServerClient/Server

http://www.rebri.org.nz/images/builder-big.jpg

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Peer-To-Peer (P2P) NetworksPeer-To-Peer (P2P) Networks

• In a P2P network each node has In a P2P network each node has equivalent capabilities and equivalent capabilities and responsibilitiesresponsibilities

• These networks are simpler than These networks are simpler than Client/Server but do not offer the Client/Server but do not offer the same performance under heavy same performance under heavy loadsloads

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Client/Server NetworksClient/Server Networks

• In a Client/Sever network each node is In a Client/Sever network each node is either a client or servereither a client or server

• Client computers run applications, but rely Client computers run applications, but rely on servers for resources such as files and on servers for resources such as files and printing capabilitiesprinting capabilities

• Servers are powerful computers that Servers are powerful computers that manage files, printers or network trafficmanage files, printers or network traffic

• This architecture is sometimes called the This architecture is sometimes called the two-tier architecturetwo-tier architecture

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ProtocolsProtocols

• Protocols are agreed Protocols are agreed formats for transmitting formats for transmitting data between devicesdata between devices66

• The protocol The protocol determines:determines:– The error checking The error checking

requiredrequired– Data compression method Data compression method

usedused– The way the end of a The way the end of a

message is signaled message is signaled TT

– The way the device The way the device indicates that it has indicates that it has received the messagereceived the message

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Internet ProtocolsInternet Protocols

• There are many protocols used by There are many protocols used by the Internet and the WWW, includingthe Internet and the WWW, including– TCP/IPTCP/IP– HTTPHTTP– FTPFTP– Electronic mail protocolsElectronic mail protocols

• IMAPIMAP

•POPPOP

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TCP/IPTCP/IP

• The Internet uses two main protocols The Internet uses two main protocols (developed by Vicent Cerf and Robert (developed by Vicent Cerf and Robert Kahn)Kahn)– Transmission control protocol (TCP)Transmission control protocol (TCP)

• Controls disassembly of message into packets at the Controls disassembly of message into packets at the originorigin

• Reassembles at the destinationReassembles at the destination

– Internet protocol (IP)Internet protocol (IP)• Specifies the addressing details for each packet Specifies the addressing details for each packet

– Each packet is labeled with its origin and destinationEach packet is labeled with its origin and destination

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Internet Protocol version 4 Internet Protocol version 4 (IPv4)(IPv4)

• Uses a 32 bit number to identify each Uses a 32 bit number to identify each computercomputer– Called the IP address (4 billion Called the IP address (4 billion

addresses)addresses)– IP addresses use the dotted decimal IP addresses use the dotted decimal

notation, e.g. 0.0.0.0 or notation, e.g. 0.0.0.0 or 255.255.255.255255.255.255.255

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Internet Protocol version 6 Internet Protocol version 6 (IPv6)(IPv6)• Set to replace version 4Set to replace version 4

• Changes the format of the packetsChanges the format of the packets– Removes unused fieldsRemoves unused fields

• Uses 128 bit number (2Uses 128 bit number (2128128 addresses) addresses)– Eight groups of 16 bitsEight groups of 16 bits

•e.g. e.g. CD18:0000:0000:AF23:0000:FF9E:61B2:884DCD18:0000:0000:AF23:0000:FF9E:61B2:884D

•To simplify zeroes may be removedTo simplify zeroes may be removed– CD18:::AF23::FF9E:61B2:884DCD18:::AF23::FF9E:61B2:884D

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Hypertext Transfer Protocol Hypertext Transfer Protocol (HTTP)(HTTP)77

• The hypertext transfer protocol (HTTP) was The hypertext transfer protocol (HTTP) was developed by Tim Berners-Lee in 1991developed by Tim Berners-Lee in 1991

• HTTP was designed to transfer pages HTTP was designed to transfer pages between machinesbetween machines

• The client (or Web browser) makes a The client (or Web browser) makes a request for a given page and the Server is request for a given page and the Server is responsible for finding it and returning it to responsible for finding it and returning it to the clientthe client

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Hypertext Transfer Protocol Hypertext Transfer Protocol (HTTP)(HTTP)

• The browser connects and requests a page from The browser connects and requests a page from the serverthe server

• The server reads the page from the file system, The server reads the page from the file system, sends it to the client and terminates the sends it to the client and terminates the connectionconnection

Client Web Server

Request sent to Web server

Response sent with files (one for eachWeb page, image, sound clip etc.)

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• Using your favourite search engine Using your favourite search engine find out more about the HTTP find out more about the HTTP protocolprotocol

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File Transfer Protocol (FTP)File Transfer Protocol (FTP)22

• FTP is a protocol that allows a user to:FTP is a protocol that allows a user to:– list files at a remote sitelist files at a remote site– Transfer files between local and remote computersTransfer files between local and remote computers

• Using FTP you can not run applications on a Using FTP you can not run applications on a remote siteremote site

• Also you can only look at the names of the files Also you can only look at the names of the files on the remote computer; rather than being on the remote computer; rather than being able to read themable to read them

• FTP is still used today; e.g. to transfer large FTP is still used today; e.g. to transfer large files between computers, or to upload Web files between computers, or to upload Web sitessites

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• Go to ftp.FreeBSD.org and get the Go to ftp.FreeBSD.org and get the file gzip.exe from the directory file gzip.exe from the directory /pub/FreeBSD/tools/pub/FreeBSD/tools

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Electronic Mail ProtocolsElectronic Mail Protocols

• Electronic mail uses the client/server Electronic mail uses the client/server modelmodel

• The oThe organisationrganisation has an email server has an email server devoted to handling emaildevoted to handling email– Stores and forwards email messagesStores and forwards email messages

• Individuals use email client software Individuals use email client software to read and send email (e.g. Microsoft to read and send email (e.g. Microsoft Outlook, or Netscape Messenger)Outlook, or Netscape Messenger)

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Electronic Mail Protocols Electronic Mail Protocols Cont’dCont’d• Simple Mail Transfer Protocol (SMTP)Simple Mail Transfer Protocol (SMTP)

– Specifies format of mail messagesSpecifies format of mail messages

• Post Office Protocol (POP) Post Office Protocol (POP) – tells the email server to:tells the email server to:

•Send mail to the user’s computer and delete Send mail to the user’s computer and delete it from the serverit from the server

•Send mail to the user’s computer and do not Send mail to the user’s computer and do not delete it from the serverdelete it from the server

•Ask whether new mail has arrivedAsk whether new mail has arrived

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Electronic Mail Protocols Electronic Mail Protocols Cont’dCont’d• Interactive Mail Access Protocol (IMAP)Interactive Mail Access Protocol (IMAP)

– Newer than POP, provides similar Newer than POP, provides similar functions with additional featuresfunctions with additional features•e.g. can send specific messages to the client e.g. can send specific messages to the client

rather than all the messagesrather than all the messages•A user can view email message headers and A user can view email message headers and

the sender’s name before downloading the the sender’s name before downloading the entire messageentire message

– Allows users to delete and search Allows users to delete and search mailboxes held on the email servermailboxes held on the email server

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Electronic Mail Protocols Electronic Mail Protocols Cont’dCont’d

• The disadvantage of POPThe disadvantage of POP– You can only access messages from one You can only access messages from one

PCPC

• The disadvantage of IMAPThe disadvantage of IMAP– Since email is stored on the email Since email is stored on the email

server, there is a need for more and server, there is a need for more and more expensive (high speed) storage more expensive (high speed) storage spacespace

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Terminal Emulation - TelnetTerminal Emulation - Telnet

• Telnet is a terminal emulation program for Telnet is a terminal emulation program for TCP/IP networksTCP/IP networks

• The telnet program runs on a local machine The telnet program runs on a local machine and allows connection to a remote machineand allows connection to a remote machine

• Commands entered through the telnet Commands entered through the telnet program will be executed on the Server; program will be executed on the Server; this gives the user the ability to control the this gives the user the ability to control the ServerServer

• To log into the Server a valid username and To log into the Server a valid username and password is requiredpassword is required

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• Use Telnet to execute an HTTP GET Use Telnet to execute an HTTP GET request to retrieve the index.html file request to retrieve the index.html file at www.google.comat www.google.com

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PingPing

• Ping is a utility for system Ping is a utility for system administrators/ webmasters to allow administrators/ webmasters to allow them to check network connectionsthem to check network connections

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• Determine the IP address of your Determine the IP address of your neighbour’s machine and ping itneighbour’s machine and ping it

7474

Connecting to the InternetConnecting to the Internet11

• What are some of What are some of the ways of the ways of connecting to the connecting to the Internet?Internet?

http://www.co.delaware.ny.us/links.htm

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Internet Connection OptionsInternet Connection Options

• Internet service providers (ISPs) provide Internet service providers (ISPs) provide several ways to connect to the Internet, several ways to connect to the Internet, including:including:– Voice grade telephone linesVoice grade telephone lines– Broadband connectionsBroadband connections– Leased linesLeased lines– WirelessWireless

• The major distinguishing factor is bandwidth The major distinguishing factor is bandwidth (the amount of data that can be transferred (the amount of data that can be transferred per unit of time)per unit of time)

7676

Bandwidth and ConnectionsBandwidth and Connections

• Symmetric connection: provides the same Symmetric connection: provides the same bandwidth in both directionsbandwidth in both directions

• Asymmetric connections: provide different Asymmetric connections: provide different bandwidths for either directionbandwidths for either direction– Upstream bandwidth (upload bandwidth): the Upstream bandwidth (upload bandwidth): the

amount of information that can travel from the amount of information that can travel from the user to the Internet in a given amount of timeuser to the Internet in a given amount of time

– Downstream bandwidth (download or downlink Downstream bandwidth (download or downlink bandwidth): the amount of information that bandwidth): the amount of information that can be transferred from the Internet to the can be transferred from the Internet to the user in an amount of timeuser in an amount of time

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Voice-grade Telephone Voice-grade Telephone ConnectionsConnections

• The most common way The most common way to connect to an ISP is to connect to an ISP is through a modem through a modem (analog) connected to (analog) connected to POTS (plain old POTS (plain old telephone service) telephone service) lineslines

• The speed of this The speed of this connection is 28 to connection is 28 to 56Kbps56Kbps

• It was typical for It was typical for computers to be computers to be shipped with built-in shipped with built-in modemsmodems

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Broadband ConnectionsBroadband Connections

• Connections that operate at speeds Connections that operate at speeds higher than 200Kbps are considered higher than 200Kbps are considered broadbandbroadband

• Two of the major broadband Two of the major broadband connections for home users and connections for home users and small businesses are:small businesses are:– Digital Subscriber Line (DSL) andDigital Subscriber Line (DSL) and– Cable modemsCable modems

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Broadband Connections Broadband Connections Cont’dCont’dDigital subscriber line Digital subscriber line

(DSL)(DSL) • Uses telephone lines and a Uses telephone lines and a

piece of equipment similar piece of equipment similar to a network switchto a network switch

• Both voice calls and an Both voice calls and an Internet connection are Internet connection are provided simultaneouslyprovided simultaneously

• The closer you are to the The closer you are to the provider’s central office, the provider’s central office, the better the servicebetter the service

• This service is not available This service is not available everywhereeverywhere http://computer.howstuffworks.com/dsl.htm

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Broadband Connections Broadband Connections Cont’dCont’d

• One of the latest broadband One of the latest broadband technologies is asymmetric digital technologies is asymmetric digital subscriber line (ADSL)subscriber line (ADSL)– Bandwidths from 100-640Kbps upstream Bandwidths from 100-640Kbps upstream

and from 1.5 to 9 Mbps downstreamand from 1.5 to 9 Mbps downstream

• For businesses a high-speed DSL For businesses a high-speed DSL (HDSL) is available(HDSL) is available– 768Kbps of symmetric bandwidth768Kbps of symmetric bandwidth

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Broadband Connections Broadband Connections Cont’dCont’dCable ModemsCable Modems

• Cable modems connect to the same Cable modems connect to the same broadband coaxial cable that serves cable broadband coaxial cable that serves cable televisiontelevision

• Upstream bandwidth of 300Kbps to 1 Mbps Upstream bandwidth of 300Kbps to 1 Mbps is provided and downstream bandwidth of is provided and downstream bandwidth of 10Mbps10Mbps

• Please note that upstream and downstream Please note that upstream and downstream bandwidths vary from provider to providerbandwidths vary from provider to provider

8282

Broadband Connections Broadband Connections Cont’dCont’dDSL v CableDSL v Cable

• DSL is a private line with no competing trafficDSL is a private line with no competing traffic

• Cable connections bandwidth vary with the Cable connections bandwidth vary with the user load (number of subscribers using the user load (number of subscribers using the service)service)

• ProblemsProblems– Web users in rural areas often do not have cable Web users in rural areas often do not have cable

access and have limited telephone access (low access and have limited telephone access (low cost voice-grade lines, rather than data-grade cost voice-grade lines, rather than data-grade lines) thus bandwidth is limited (<14Kbps)lines) thus bandwidth is limited (<14Kbps)

8383


• Using your favourite search engine, Using your favourite search engine, determine the most recent speeds of determine the most recent speeds of the following Internet connection the following Internet connection options:options:– Cable modemCable modem– DSLDSL

8484

Leased-Line ConnectionsLeased-Line Connections

• Large firms with large amounts of Internet Large firms with large amounts of Internet traffic can lease lines from traffic can lease lines from telecommunication carrierstelecommunication carriers

• Various technologies are used; classified by Various technologies are used; classified by the amount of telephone lines they include:the amount of telephone lines they include:– DS0 (digital signal zero) carries one digital signal DS0 (digital signal zero) carries one digital signal

(64Kbps)(64Kbps)– T1 (or DS1) carries 24 DS0 lines (1.544Mbps)T1 (or DS1) carries 24 DS0 lines (1.544Mbps)– Fractional T1 (128Kbps and upwards)Fractional T1 (128Kbps and upwards)– T3 (or DS3) carries 30 T1 lines (44.736Mbps)T3 (or DS3) carries 30 T1 lines (44.736Mbps)

• These connections more expensive than POTS and DSLThese connections more expensive than POTS and DSL

8585

Wireless ConnectionsWireless Connections

• SatelliteSatellite

• BluetoothBluetooth

• Wireless Ethernet (Wi-Fi)Wireless Ethernet (Wi-Fi)

• Fixed-Point WirelessFixed-Point Wireless

• Cellular Telephone NetworksCellular Telephone Networks

8686


SatelliteSatellite

• Satellite microwave Satellite microwave transmissionstransmissions– Customer places Customer places

receiving dish in yardreceiving dish in yard– Download bandwidth of Download bandwidth of

around 500 kbpsaround 500 kbps– Maximum upload Maximum upload

bandwidth of 150kbps bandwidth of 150kbps – Self installation makes Self installation makes

cost lowercost lower

http://www.ccpo.odu.edu/~arnoldo/ocean405/satellite.gif

8787


BluetoothBluetooth• One of the first wireless One of the first wireless

protocolsprotocols• Operates reliably over Operates reliably over

35 feet and can be part 35 feet and can be part of up to 10 networks of of up to 10 networks of eight devices each eight devices each (personal area (personal area networks, or PANs)networks, or PANs)

• Bandwidth of 722kbpsBandwidth of 722kbps• Good for wireless Good for wireless

printingprintinghttp://www.bakercountyhealth.org/services/dental/blue-tooth.jpg

8888


Bluetooth AdvantagesBluetooth Advantages

• Bluetooth technology consumes very Bluetooth technology consumes very little powerlittle power

• Bluetooth devices can discover each Bluetooth devices can discover each other and exchange information other and exchange information automatically (e.g. a user can print automatically (e.g. a user can print to a printer on a network without to a printer on a network without logging on)logging on)

8989


Wireless Ethernet Wireless Ethernet (Wi-Fi) (802.11b)(Wi-Fi) (802.11b)

• Most common wireless Most common wireless on LANson LANs

• Bandwidth 11Mbps at Bandwidth 11Mbps at 300 feet300 feet

• A computer with a Wi-A computer with a Wi-Fi network can Fi network can communicate with a communicate with a wireless access point wireless access point (WAP) to become a (WAP) to become a part of the networkpart of the network

http://www.homenethelp.com/web/diagram/images/shareing-soft-wireless.gif

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Wireless Ethernet AdvantagesWireless Ethernet Advantages

• Wi-Fi devices can roam, i.e. shift Wi-Fi devices can roam, i.e. shift from one WAP to another without from one WAP to another without user interventionuser intervention

• Increasingly WAPs are becoming Increasingly WAPs are becoming available in public places, e.g. available in public places, e.g. airportsairports

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Wireless Ethernet DevelopmentsWireless Ethernet Developments• In 2002 an improved version of Wi-Fi, called In 2002 an improved version of Wi-Fi, called

802.11a was introduced802.11a was introduced– The 802.11a protocol can transmit at speeds up to The 802.11a protocol can transmit at speeds up to

54Mbps54Mbps– 802.11a is not compatible with 802.11b802.11a is not compatible with 802.11b

• Later in 2002, the 802.11g protocol was Later in 2002, the 802.11g protocol was introduced which is compatible with 802.11b introduced which is compatible with 802.11b devices and has speeds of 54Mbpsdevices and has speeds of 54Mbps

• In 2004-2005, 802.11n was expected (320Mbps)In 2004-2005, 802.11n was expected (320Mbps)– In January 2006 the 802.11n proposal was confirmed In January 2006 the 802.11n proposal was confirmed

and manufacturers began supplying chips with and manufacturers began supplying chips with throughput of 300Mbps - 600Mbps for samplingthroughput of 300Mbps - 600Mbps for sampling

9292


Fixed Point WirelessFixed Point Wireless• Uses a system of Uses a system of

repeaters (transmitter-repeaters (transmitter-receiver devices) to receiver devices) to forward a radio signal forward a radio signal from the ISP to from the ISP to customerscustomers

• Users’ antennas are Users’ antennas are connected to a device connected to a device that converts radio that converts radio signals to Wi-Fi signals to Wi-Fi packets which are sent packets which are sent to their computersto their computers

http://www.erinc.com/apps_wireless/images/fixed_wireless2.gif

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Cellular Telephone Cellular Telephone NetworksNetworks

• In 2003, about 500 In 2003, about 500 million mobile (cell) million mobile (cell) phones existed worldwidephones existed worldwide

• Originally slow data Originally slow data communication (10 kbps communication (10 kbps – 384kbps)– 384kbps)

• Third generation cell Third generation cell phonesphones– Up to 2 MbpsUp to 2 Mbps

http://www.mtco.com/graphics/cellularpic.jpg

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Cellular Telephone Networks Cont’dCellular Telephone Networks Cont’d• Cell phones send and receive messages Cell phones send and receive messages

using the short message service (SMS) using the short message service (SMS) protocolprotocol

• Some cell phones (e.g. the Blackberry, Some cell phones (e.g. the Blackberry, http://www.blackberry.comhttp://www.blackberry.com) include:) include:– a Web browser which provides web accessa Web browser which provides web access– EmailEmail– short message service (sms)short message service (sms)– Instant messagingInstant messaging

http://www.blackberry.com/

9595


Cellular Telephone Networks Cont’dCellular Telephone Networks Cont’d• Cell phones send and receive messages using Cell phones send and receive messages using

the short message service (SMS) protocolthe short message service (SMS) protocol• Companies also sell Internet access through Companies also sell Internet access through

their cellular networkstheir cellular networks– Fixed fee plus charge for amount of data Fixed fee plus charge for amount of data

transferredtransferred

• Business potential of mobile commerceBusiness potential of mobile commerce– Companies are identifying the kinds of resources Companies are identifying the kinds of resources

individuals might want to access (and pay for) using individuals might want to access (and pay for) using wireless deviceswireless devices

9696

The OSI ModelThe OSI Model99

• The Open Systems Interconnect Model (OSI):The Open Systems Interconnect Model (OSI):– provides a fundamental understanding of network provides a fundamental understanding of network

data transmission through a set of guidelinesdata transmission through a set of guidelines– Promotes interoperabilityPromotes interoperability– Describes the tasks a protocol suite (the set of Describes the tasks a protocol suite (the set of

rules used which allow computers to rules used which allow computers to communicate) performcommunicate) perform

– Developed in 1977 by the International Developed in 1977 by the International Organization for Standardization (ISO)Organization for Standardization (ISO)

9797

The OSI Model (Cont’d)The OSI Model (Cont’d)

• The OSI model The OSI model consists of seven consists of seven layerslayers– Each layer performs Each layer performs

a particular function a particular function and passes the and passes the result to the next result to the next layerlayer

http://static.howstuffworks.com/gif/osi-model.jpg

9898


• The Application layer:The Application layer:– Refers to tools that an application can Refers to tools that an application can

use to complete a task, e.g. spreadsheet use to complete a task, e.g. spreadsheet software requesting a file transfersoftware requesting a file transfer

– Defines how network services interact Defines how network services interact with the networkwith the network•These services include file, print and These services include file, print and

messaging servicesmessaging services

9999


• The Presentation Layer:The Presentation Layer:– Responsible for formatting data that will Responsible for formatting data that will

be exchangedbe exchanged•Data encryptionData encryption

•Converting character setsConverting character sets

•Data CompressionData Compression

100100


• The Session Layer:The Session Layer:– Specifies how two computers establish, Specifies how two computers establish,

synchronise, maintain and end a sessionsynchronise, maintain and end a session•Security authenticationSecurity authentication

•Data transferData transfer

•AcknowledgementsAcknowledgements

•Connection releaseConnection release

101101


• The Transport Layer:The Transport Layer:– Ensures that data is transmitted error freeEnsures that data is transmitted error free– Breaks long messages into smaller chunks Breaks long messages into smaller chunks

and recompiles themand recompiles them– Combines short messages into longer Combines short messages into longer

chunkschunks– Logical name resolutionLogical name resolution– Acknowledges packet receiptAcknowledges packet receipt

102102


• The Network Layer:The Network Layer:– Defines protocols to ensure that data Defines protocols to ensure that data

arrives at the correct destinationarrives at the correct destination•Relies on logical network addresses (e.g. IP Relies on logical network addresses (e.g. IP

addresses)addresses)

103103


• The Data Link Layer:The Data Link Layer:– Creates, transmits and receives packetsCreates, transmits and receives packets– Is responsible for:Is responsible for:

• the physical address (MAC)the physical address (MAC)

•Creating logical topologiesCreating logical topologies

104104


• The Physical Layer:The Physical Layer:– Converts data into electrical signalsConverts data into electrical signals

• i.e. converts 1 and 0 bits to voltages to pass i.e. converts 1 and 0 bits to voltages to pass allow the medium (e.g. a cable)allow the medium (e.g. a cable)

– Determines the amount of media that Determines the amount of media that will be usedwill be used

– Is responsible for the physical topologyIs responsible for the physical topology

105105

Network DevicesNetwork Devices

• Several devices are used in networks Several devices are used in networks including:including:– HubsHubs– SwitchesSwitches– BridgesBridges– RoutersRouters

106106

Network Devices (Cont’d)Network Devices (Cont’d)

HubHub• A hub is a central connection point A hub is a central connection point

for several network devicesfor several network devices• There are two types of hubs:There are two types of hubs:

– An active hub is usually poweredAn active hub is usually powered•Amplifies and cleans up the signal it receivesAmplifies and cleans up the signal it receives

– A passive hub is not poweredA passive hub is not powered•Uses some of the signal strength in order to Uses some of the signal strength in order to

operate -- operates over shorter distancesoperate -- operates over shorter distances

107107


Switch (or Switching Hub)Switch (or Switching Hub)

• A switch builds a table of the MAC addresses A switch builds a table of the MAC addresses of the devices connected to itof the devices connected to it

• When the switch receives the data, the When the switch receives the data, the actual node that the data needs to be sent actual node that the data needs to be sent to is determined and the data sent to that to is determined and the data sent to that nodenode– This is the difference between a switch and a This is the difference between a switch and a

hub, since the hub sends all the messages to all hub, since the hub sends all the messages to all connected nodesconnected nodes

108108


BridgeBridge

• A bridge logically separates a single A bridge logically separates a single network into two segmentsnetwork into two segments

• This is useful when you have one or more This is useful when you have one or more servers (for example) on the network that servers (for example) on the network that are heavily used and others that are notare heavily used and others that are not– By separating the network with a bridge, the By separating the network with a bridge, the

performance of the part of the network that is performance of the part of the network that is less active is not compromisedless active is not compromised

109109


RouterRouter• Routing is the process of moving Routing is the process of moving

data through a network using routersdata through a network using routers• Routers store information about Routers store information about

which routes packets can take to get which routes packets can take to get to their destinations on files called to their destinations on files called routing tablesrouting tables– Only packets with specified destinations Only packets with specified destinations

will be routedwill be routed

110110

Electronic Commerce Electronic Commerce SoftwareSoftware

• What are some of What are some of the software the software requirements for requirements for an e-commerce an e-commerce site?site?

111111

Electronic Commerce Software Electronic Commerce Software Cont’dCont’d

• The software requirements for e-The software requirements for e-commerce sites vary tremendously commerce sites vary tremendously and are dependent on several factors and are dependent on several factors including:including:– The size of the enterprise and its The size of the enterprise and its

projected trafficprojected traffic– The budgetThe budget

112112

Electronic Commerce Electronic Commerce Software Cont’dSoftware Cont’d

• All e-commerce solutions must All e-commerce solutions must provide at least the following:provide at least the following:– A catalog displayA catalog display– Shopping cart capabilitiesShopping cart capabilities– Transaction processingTransaction processing

113113

Electronic Commerce Electronic Commerce Software Cont’dSoftware Cont’d

• Larger e-commerce sites require additional Larger e-commerce sites require additional functionality, such as:functionality, such as:– Middleware that links the company’s existing Middleware that links the company’s existing

system (inventory control, order processing system (inventory control, order processing and accounting) to the e-commerce systemand accounting) to the e-commerce system

– Databases and ApplicationsDatabases and Applications– Supply chain management softwareSupply chain management software– Customer relationship management softwareCustomer relationship management software– Content management softwareContent management software– Knowledge management softwareKnowledge management software

114114


• Using your favourite search engine Using your favourite search engine find examples of:find examples of:– Supply chain management softwareSupply chain management software– Customer relationship management Customer relationship management

softwaresoftware– Content management softwareContent management software– Knowledge management softwareKnowledge management software

115115

ToolsTools

• Several tools have been created to allow Several tools have been created to allow the easy generation of web pages the easy generation of web pages including:including:– Microsoft FrontPageMicrosoft FrontPage– Microsoft OfficeMicrosoft Office– Macromedia DreamweaverMacromedia Dreamweaver

• These tools are useful since they allow These tools are useful since they allow people with very little knowledge of HTML people with very little knowledge of HTML to create web pagesto create web pages

116116

Tools (Cont’d)Tools (Cont’d)

• It is important to be careful with It is important to be careful with tools, however since the code that is tools, however since the code that is automatically generated may be automatically generated may be difficult to decipher if a problem does difficult to decipher if a problem does occuroccur

117117


• Create a simple web page using Create a simple web page using Microsoft Word and carefully Microsoft Word and carefully examine the HTML codeexamine the HTML code– How does it differ from the HTML code How does it differ from the HTML code

that you would write if you were using a that you would write if you were using a simple text editor?simple text editor?

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ReferencesReferences

[[11]] Schneider, Gary, P., “Electronic Commerce: The second wave”, Thomson Course Schneider, Gary, P., “Electronic Commerce: The second wave”, Thomson Course Technology, Fifth Annual Edition, 2004Technology, Fifth Annual Edition, 2004

[2] Zhao, Jensen J., “Web design and development for e-business”, Prentice Hall, [2] Zhao, Jensen J., “Web design and development for e-business”, Prentice Hall, 20032003

[3] Federal Networking Council, “FNC Resolution: Definition of the Internet”, 1995. [3] Federal Networking Council, “FNC Resolution: Definition of the Internet”, 1995. Online document available at Online document available at http://www.itrd.gov/fnc/Internet_res.htmlhttp://www.itrd.gov/fnc/Internet_res.html

[4] NetCraft, “[4] NetCraft, “April 2004 Web Server SurveyApril 2004 Web Server Survey”, 2004. Online document available at ”, 2004. Online document available at http://news.netcraft.com/archives/2004/04/01/april_2004_web_server_survey.hthttp://news.netcraft.com/archives/2004/04/01/april_2004_web_server_survey.htmlml

[5] Furdyk, Michael, “Ultimate Guide to Networking: Part One”, 1999. Online [5] Furdyk, Michael, “Ultimate Guide to Networking: Part One”, 1999. Online document available at document available at http://www.hardwarecentral.com/hardwarecentral/print/158/http://www.hardwarecentral.com/hardwarecentral/print/158/

[6] Webopedia, “Network”, 2004. Online document available at [6] Webopedia, “Network”, 2004. Online document available at http://networking.webopedia.com/TERM/N/network.htmlhttp://networking.webopedia.com/TERM/N/network.html

[7] Berlin, Dan, et al., “CGI Programming Unleased”, Sams.net Publishing, 1996, pp. [7] Berlin, Dan, et al., “CGI Programming Unleased”, Sams.net Publishing, 1996, pp. 101-102101-102

[8] [8] NetCraft, “NetCraft, “April 2006 Web Server SurveyApril 2006 Web Server Survey”, 2006. Online document available at ”, 2006. Online document available at http://news.netcraft.com/archives/web_server_survey.htmlhttp://news.netcraft.com/archives/web_server_survey.html

[9] Sybex Inc, “Networking Complete”, Sybex, Inc, Third Edition, 2002[9] Sybex Inc, “Networking Complete”, Sybex, Inc, Third Edition, 2002

http://www.itrd.gov/fnc/Internet_res.html

http://news.netcraft.com/archives/2004/04/01/april_2004_web_server_survey.html

http://news.netcraft.com/archives/2004/04/01/april_2004_web_server_survey.html

http://www.hardwarecentral.com/hardwarecentral/print/158/

http://networking.webopedia.com/TERM/N/network.html

http://news.netcraft.com/archives/web_server_survey.html

web technologies comp6115 session 1: internetworking and the world wide web dr. paul walcott...

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