chapter1 - the internet and www

8/8/2019 Chapter1 - The Internet and WWW

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Web Programming

Dr. Nguyen Tuan NamFall 2010


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Learning Outcomes

Create dynamical web pages that are tailoredto specific user requests

Understand the basics of HTML, CSS, XHTMLControl page layout using CSSIncorporate external media into a web pageUse W3C to validate HTML, CSS and XHTML

Understand the basic steps of building anecommerce websiteSetup and maintain the Apache web server,PHP subsystem, JSP, Java Servlet, MySQL

DBMSUtilize MySQL DBMS for data storage andretrieval


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Textbooks

Textbooks[1] Beginning PHP5, Apache, MySQL Web Development.E. Naramore, J. Gerner, Y. Scouarnec, J. Stolz, M. Glass.

Wiley Publishing. 2005[2] Java Web Programming . David Turner and Jinsok Chae. 2009[3] Sams Teach Yourself Ajax, JavaScript, and PHP All in One. Ballard and Moncur. Sams, 2008.[4] Sams Teach Yourself HTML and CSS in 24 Hours.Dick Oliver and Michael Morrison, 7th Edition, 2005.

WebsitesXHTML reference http://xhtml.com/en/xhtml/reference/HTML referencehttp://www.w3schools.com/html/default.asp


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Assignment & GradingMidterm exam

On the 5 th week (5 weeks from today)30%

Final examTBD40%

Projects30%

Extra credits AttendanceParticipation


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The Internet and WWW

Chapter 1Key Concepts


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Learning

OutcomesIn this chapter, you will learn about:

The evolution of the Internet, Internetstandards organizations, and the differencebetween the Internet, intranets, andextranets.The beginning of the World Wide Web,ethical use of information on the Web,Web Accessibility, and future Internettrends.The Client/Server Model, InternetProtocols, Networks, URLs and DomainNames, and Markup Languages.


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he Evolutionof the Internet

InternetInter connected net work of computer networks

ARPAnet Advanced Research Project Agency1969 four computers connected

NSFnetNational Science FoundationBackbone speed of 56Kbps

Use of the Internet was originally limited togovernment, research and academic use

1991 Commercial ban lifted


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Intranet & Extranets

Intranet A private network contained within anorganization or business used to shareinformation and resources among coworkers.

Extranet A private network that securely shares part of an organizations information or operations with

external partners


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Growth of InternetHobbes Internet Timeline

http://www.zakon.org/robert/internet/timeline/

Year

196919891992199520012002200320062009

Host Computers

4100,0001,000,0008,000,000

109,000,000147,000,000171,600,000439,000,000700,000,000


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Reasons forInternet Growth in the 1990s

Removal of the ban on commercial activity

Development of the World Wide Web byTim Berners-Lee at CERN

1990

Development of Mosaic, the first graphics-

based web browser at NCSA 1992-1997


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The World Wide WebThe graphical user interface to

information stored on some of thecomputers connected to the Internet.


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Mosaic 1.0


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Internet Standards &

CoordinationThe Internet Society

A professional organization thatprovides leadership in addressing issuesrelated to the future of the Internet

IETF-- Internet Engineering Task ForceRFC Requests for Comments

IAB Internet Architecture Board


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Internet Standards &

CoordinationICANN - The Internet Corporation for

Assigned Numbers & NamesNon-profit organizationMain function is to coordinate theassignment of:

Internet domain namesIP address numbers

Protocol parametersProtocol port numbers.


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Web Standards

and the W3C ConsortiumW3C World Wide Web Consortium

Develops recommendations andprototype technologies related to theWeb

Produces specifications, calledRecommendations, in an effort to

standardize web technologies

WAI Web Accessibility Initiative


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Web

AccessibilityWAI Web Accessibility Initiative

Develops recommendations forweb content developers,web authoring tool developers,developers of web browsers, and

developers of other user agents to facilitate use of the web by those with special needs.

WCAGWeb Content Accessibility Guidelineshttp://www.w3.org/WAI/WCAG20/quickref/


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Web

AccessibilitySection 508 of the Rehabilitation

Actrequires that government agenciesmust give individuals with disabilities

access to information technology thatis comparable to the access availableto others


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Checkpoint 1.11. Describe the difference between the Internet and an intranet.

2. Explain three events that contributed

to the commercialization and exponential growth of the Internet.

3. Describe the difference between the Internet and the Web.


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Network

OverviewNetwork -- two or more computers connectedtogether for the purpose of communicating andsharing resources


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NetworksLAN -- Local Area Network

Usually confined to a single building or group of

buildingsUsually high-speed and relatively inexpensive

MAN -- Metropolitan Area Network Connects computer resources in a localgeographical area

WAN -- Wide Area Network Usually uses some form of public or commercialcommunications network to connect computersin widely dispersed geographical areas.


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A WAN connecting

two LANs


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Internet

InfrastructureInternet Backbone

A high capacitycommunication link that carries datagathered from smallerlinks that interconnect

with it.N AP N etw o rk

Access Point Access points or junctions to theInternet Backbone inmajor cities.


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he Client/Server

Model

Client/Server can describe a relationshipbetween two computer programs the"client " and the " server ".

Clientrequests some type of service (such as a fileor database access) from the server.

Serverfulfills the request and transmits the results tothe client over a network


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he Client/Server

Model

The Internet Client/Server ModelClient -- Web BrowserServer -- Web Server


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Web

ClientConnected to the Internet when needed

Usually runs web browser (client)software such as Internet Explorer orNetscape

Uses HTTP (Hypertext Transfer Protocol)Requests web pages from serverReceives web pages and files from server


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MIME

TypeMulti-Purpose Internet Mail Extension

A set of rules that allowmultimedia documentsto be exchanged amongmany different computer systems

A specification for formatting non-ASCIImessages so that they can be sent overthe Internet

Composed of Type Subtype Optional parameters


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Internet

ProtocolsProtocols

Rules that describe the methods usedfor clients and servers to communicatewith each other over a network.

There is no single protocol that makes theInternet and Web work.

A number of protocols with specificfunctions are needed.


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E-mail

ProtocolsSending E-mail

SMTP Simple Mail Transfer Protocol

Receiving E-mail

POP (POP3) Post Office ProtocolIMAP Internet Mail Access Protocol


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HTTP

Hypertext Transfer Protocol A set of rules for exchanging files such astext, graphic images, sound, video, andother multimedia files on the Web.

Web browsers send HTTP requests for web pagesand their associated files.

Web servers send HTTP responses back to the

web browsers.

HTTP Request

HTTP Response


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TCP/IPTransmission Control Protocol/ Internet P rotocol

TCP/IP has been adopted as theofficial communication protocol of theInternet.

TCP and IP have different functionsthat work together to ensure reliablecommunication over the Internet.


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CP

Transmission Control ProtocolPurpose is to ensure the integrity of communicationBreaks files and messages into individual unitscalled packets

IP


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IP

Internet Protocol A set of rules that controls how data is sentbetween computers on the Internet.

IP routes a packet to the correctdestination address.

The packet gets successively forwarded tothe next closest router (a hardware device

designed to move network traffic) until itreaches its destination.http://visualroute.visualware.com/

http://www.tracert.com/cgi-bin/trace.pl


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IP AddressEach device connected to the Internet hasa unique numeric IP address.

These addresses consist of a set of fourgroups of numbers, called octets.64.233.167.99 will get you Google!

An IP address may correspond to a domain

name.

D i


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Domain

NameLocates an organization or otherentity on the Internet

Domain Name SystemDivides the Internet into logicalgroups and understandable names

Associates unique computer IP Addresses with the text-baseddomain names you type into a web

browserBrowser: http://google.comDNS: 64.233.187.99

URL


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URL

Uniform Resource Locator

URLRepresents theaddress of aresource on theInternet .


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Co nt Code


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County Code

TLDsTwo character codes originally intended toindicate the geographical location (country)

of the web site.

In practice, it is fairly easy to obtain adomain name with a country code TLD thatis not local to the registrant.

Examples:.tv, .ws, .au, .jp, .uk See http://www.iana.org/cctld/cctld-whois.htm


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Markup

Language Annotating a text in a way that issyntactically distinguishable from thattext

Markup is typically omitted from theversion of the text which is displayedfor end-user consumption


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Types of Electronic MarkupPresentational

Embedded in document text

Produces the WYSIWYGeffectProceduralEmbedded in textProvides instructions for programs that are to

process the textEx: LaTeX, PostScriptDescriptive

Used to label parts of the documentNot providing specific instructions as to howthey should be processedEx: HTML's tag

M k


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Markup

LanguagesSGML Standard Generalized MarkupLanguage

A standard for specifying a markuplanguage or tag set

HTML Hypertext Markup LanguageThe set of markup symbols or codes

placed in a file intended for display on aweb browser.

Markup


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Markup

Languages (2)XML eXtensible Markup Language

Subset of SGML

A text-based language designed to describe,deliver, and exchange structured information.

It is not intended to replace HTML it is intended to extend the power of HTML byseparating data from presentation.

Markup


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Markup

Languages (3)XHTML eXtensible Hypertext MarkupLanguage

Developed by the W3C as the reformulation of HTML 4.0 as an application of XML.

It combines the formatting strengths of HTML4.0 and the data structure and extensibilitystrengths of XML.

Markup


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Markup

Languages (4)HTML 5

The next version of HTML 4 and XHTML 1

http://www.w3.org/html/

Markup


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Markup

Languages (5)The relationship betweenXHTML, HTML, and XML

Most Important Differences


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Most Important Differences

Between HTML and XHTMLXHTML elements must be properlynestedXHTML elements must always beclosed

XHTML elements must be inlowercaseXHTML documents must have oneroot element


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Checkpoint 1.21. Describe the components of the client/server model as applied to the Internet.

2. Identify two protocols used on the Internet to convey information that use the Internet but do not use the Web.

3. Explain the similarities and differences between a URL and a domain name.

Future Internet


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Future Internet

& Web TrendsContinued importance of E-CommerceWireless Web access

Need for skilled technical workersIPV6Web Services

BlogsRSSWikisWeb 2.0Constant Change!


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SummaryThis chapter provided a brief overview of Internet, Web, andintroductory networking concepts.

chapter1 - the internet and www

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