© minder chen, 1996-2013 web architecture - 1 the architecture of internet and www web browser...

© Minder Chen, 1996-2013 Web Architecture - 1

The Architecture of Internet and WWW

Web Browser

Client

Web Server

End User

HTTPTCP/IP

HTML documents

Internetor

Intranet

Benefits of the Web as a delivery mechanism: •Thin clients•Platform independence•Easy for deployment/upgrade•Based on standards


Internet: The Virtual Network & Internal Structure

Computer

Router

A Regional Network

Internet

NAP

ISP

LAN

NAP: National Access Point ISP: Internet Service Provider

TELCO


Hosts on the Internet• IP Datagram

– Datagram Header• Source: 15.127.9.12 (IP Address)• Destination: 254.231.15.129

• American Registry for Internet Numbers https://www.arin.net/

Router

Total about 4.3 billion IP addresses.


Domain Name• DNS (Domain Name Server): Mapping the four octets (32-bit numeric) IP

address (such as 217.156.3.14) to a domain name such as student.csuci.edu

• http://www.godaddy.com for domain name registration

edu uiuc

csuci

csvax

The name of a host computer with an IP address

student

First Level

Second Level

CSUCI.EDU

Top country domain name.us.tv (30M).md

http://www.godaddy.com/


Key Elements of Web• Hypertext: Non-linear links to anchors of the

same document, or to different documents on the same or different web site. – Using HTML (HyperText Markup Language) links and

anchors– Relying on URL (Uniform Resource Locators)

addressing scheme

• Multimedia: graphics, video, sound, etc. – Web browser can access networked hypermedia. – Hypermedia access of the web browser is facilitated

by helper applications, plug-ins, or document viewers.

• Network: Global reach and "Universal" access– Based on HTTP which is built on top of the TCP/IP

protocol.


Client-Server Model of http

Web Server

Web Client

• Requesting a document via a URL address

• Connection open

• Returning MIME-compliance document

• Connection close

help

er app

help

er app

help

er app

help

er app

help

er app

Web contents• HTML documents• Images• Animation• Video clips• Sound bites• Java applets• Java Scripts• CGI scripts• JSP• Database access• ASP/ASPX/PHP• JSP

Web Site

Internet or Intranet

1

2

Static

Dynamic

MIME: Multipurpose Internet Mail Extension


HTTP

• HTTP: HyperText Transfer Protocol• Characteristics:

– Runs on top of TCP/IP (Transmission Control Protocol/Internet Protocol)

– Has a comprehensive addressing scheme, i.e. URL– An extensible and open representation for data type,

using MIME header

– Has a stateless protocol. There is no memory between client connections. Cookies are used to track users.

– Is efficient– Is portable – Possible extensions, Secure HTTP (SHPPT), SSL.

(https://URL)


The Extended Framework of WWW

Web Browser

Client

HTML Authoring Tools/Editors

End User Web Master

Web Designer& Publisher

External ApplicationsNon-HTTP objects

• ColdFusion, • CGI (Perl)• ASP & ASP.NET• JAVA Servlet• Java Server

Pages • Java Applet• JavaScript

Internet Global Reach Broad Range

Web Programmer

Web Server

<html> <head> <title> HTML Sampler Web Page </title></head><body> <h1>HTML Sampler</h1><img src="eyes.gif"><br><b> List: </b> <ul> <li> Item 1<li> <font size=+2>Item 2</font><li> <i>Item 3</i></ul> <table border=1> <tr> <th> Name</th> <th>Speciality </th> </tr><tr> <td> Minder Chen</td> <td>MIS </td> </tr><tr> <td> Justin Chen</td> <td>Aerospace </td> </tr></table> <p>A sample of a form: <form method="post" action="http://hoohoo.ncsa.uiuc.edu/cgi-bin/post-query" > Name: <input type="text" size=20> <br><input type="checkbox" name="html" value="YES"> Know HTML <br><b><input type="submit" value="Submit your data"></b></form><hr> Developed by <a href="http://www.erols.com/aitc/"> Advanced IT Consulting</a> </body></html>

image

list

table

form

link


HTTP (Web) Cookie

• First party and third party Cookies at http://on.wsj.com/LamyJX

This is how most web sites used to track you and maintain online sessions.


Clickstream• Hit – any Web server request that generates a log file entry. A

page has many elements (html, gifs), each generating a hit.• Page – Web server file that is sent to client user agent, usually a

browser. • Session – all actions (i.e. requests, resets) made in single visit,

from entry until logout or time out (e.g., 20 minutes of no activity).

• Visitor – a user or bot/spider/crawler that makes requests at a site. Can be new, returning, registered, anonymous

• Buyer – visitor that purchases something• Customer – a visitor that registers (sometimes defined as buyer)• Conversion – rate at which visitors transition to desired state• (buyers, customers, registered, started checkout)• Host – remote machine, identified by IP address, used for visit.• Referrers – page that provides a link to another page. Can be

internal or external


Web Log Analysis• Number of visits and number of unique visitors

• Visits duration and last visits

• Authenticated users, and last authenticated visits

• Days of week and rush hours

• Domains/countries of host's visitors.

• Hosts list

• Number total pageviews

• Most viewed, entry and exit pages

• Files type

• OS used

• Browsers used

• Robots

• HTTP referrer

• Search engines, key phrases and keywords used to find the analyzed web site

• HTTP errors

• Some of the log analyzers also report on who's on the site, conversion tracking, visit time and page navigation.

© minder chen, 1996-2013 web architecture - 1 the architecture of internet and www web browser...

Documents