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The Architecture of Internet and WWW. Benefits of the Web as a delivery mechanism: Thin clients Platform independence Easy for deployment/upgrade Based on standards . HTML documents. Web Browser. HTTP TCP/IP. Client. End User. Internet or Intranet. Web Server.
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The Architecture of Internet and WWW • Benefits of the Web as a delivery mechanism: • Thin clients • Platform independence • Easy for deployment/upgrade • Based on standards HTML documents Web Browser HTTP TCP/IP Client End User Internet or Intranet Web Server
Internet: The Virtual Network & Internal Structure NAP ISP A Regional Network Computer TELCO Router Internet LAN NAP: National Access Point ISP: Internet Service Provider
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/ Total about 4.3 billion IP addresses. Router
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 The name of a host computer with an IP address CSUCI.EDU edu uiuc Top country domain name .us .tv (30M) .md cs vax First Level csuci student Second Level
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 1 Web Site • Requesting a document via a URL address • Connection open Web Server helper app helper app helper app helper app helper app • Web contents • HTML documents • Images • Animation • Video clips • Sound bites • Java applets • Java Scripts • CGI scripts • JSP • Database access • ASP/ASPX/PHP • JSP Internet or Intranet Web Client Static 2 Dynamic • Returning MIME-compliance document • Connection close 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 HTML Authoring Tools/Editors External Applications Non-HTTP objects Web Designer & Publisher • ColdFusion, • CGI (Perl) • ASP & ASP.NET • JAVA Servlet • Java Server Pages • Java Applet • JavaScript Web Programmer Web Browser Internet Global Reach Broad Range Web Server Client Web Master End User
<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 This is how most web sites used to track you and maintain online sessions. First party and third party Cookies at http://on.wsj.com/LamyJX
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.