9781423903055 ppt ch08

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9781423903055 ppt ch08

  1. 1. Electronic Commerce Eighth Edition Chapter 8 Web Server Hardware and Software
  2. 2. Learning Objectives <ul><li>In this chapter, you will learn about: </li></ul><ul><li>Web server basics </li></ul><ul><li>Software for Web servers </li></ul><ul><li>E-mail management and spam control issues </li></ul><ul><li>Internet and Web site utility programs </li></ul><ul><li>Web server hardware </li></ul>Electronic Commerce, Eighth Edition
  3. 3. Web Server Basics <ul><li>Chapter topics </li></ul><ul><ul><li>Basic technologies to build online business Web sites </li></ul></ul><ul><ul><ul><li>Server software and hardware </li></ul></ul></ul><ul><ul><ul><li>Utility function software </li></ul></ul></ul><ul><ul><li>Web server </li></ul></ul><ul><ul><ul><li>Main job: respond to Web client requests </li></ul></ul></ul><ul><ul><ul><li>Main elements: hardware, operating system software, Web server software </li></ul></ul></ul><ul><ul><li>Web site goals followed by site development </li></ul></ul><ul><ul><ul><li>Perform site estimates </li></ul></ul></ul><ul><ul><ul><li>Determine hardware and software combination </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  4. 4. Types of Web Sites <ul><li>Web site planning is first step </li></ul><ul><ul><li>Determine site goals </li></ul></ul><ul><ul><ul><li>Estimate visitors, types of files </li></ul></ul></ul><ul><ul><ul><li>Assess existing information technology staff </li></ul></ul></ul><ul><li>Five Web site categories </li></ul><ul><ul><li>Development sites: evaluate Web designs </li></ul></ul><ul><ul><li>Intranets: house internal information </li></ul></ul><ul><ul><li>Extranets: allow outside party access </li></ul></ul><ul><ul><li>Transaction-processing sites: commerce site </li></ul></ul><ul><ul><li>Content-delivery sites: deliver news, histories, summaries, digital content </li></ul></ul>Electronic Commerce, Eighth Edition
  5. 5. Web Clients and Web Servers <ul><li>Client/server architectures </li></ul><ul><ul><li>Client requests services from server </li></ul></ul><ul><li>Client computer </li></ul><ul><ul><li>Uses Web browser software (Web client software) </li></ul></ul><ul><li>Server computer </li></ul><ul><ul><li>More memory and larger, faster disk drives </li></ul></ul><ul><li>Platform neutral Web software </li></ul><ul><ul><li>Various computers communicate easily, effectively </li></ul></ul><ul><ul><li>Critical ingredient for rapid spread, widespread Web acceptance </li></ul></ul>Electronic Commerce, Eighth Edition
  6. 6. Electronic Commerce, Eighth Edition
  7. 7. Dynamic Content <ul><li>Server performance affected by: </li></ul><ul><ul><li>Web page mix and type delivered to client </li></ul></ul><ul><li>Dynamic page </li></ul><ul><ul><li>Client Web page content shaped by program </li></ul></ul><ul><li>Static page </li></ul><ul><ul><li>Unchanging page retrieved from disk </li></ul></ul><ul><ul><li>Sometimes stored in Web server’s active memory </li></ul></ul><ul><li>Static versus dynamic page delivery </li></ul><ul><ul><li>Static page requires less computing power </li></ul></ul><ul><ul><li>Servers delivering mostly static pages perform better </li></ul></ul>Electronic Commerce, Eighth Edition
  8. 8. Dynamic Content (cont’d.) <ul><li>Dynamic content </li></ul><ul><ul><li>Nonstatic information constructed in response to Web client’s request </li></ul></ul><ul><ul><li>Example: order inquiry with unique customer number </li></ul></ul><ul><li>Web sites using collection of HTML pages </li></ul><ul><ul><li>Changed by editing HTML (cumbersome) </li></ul></ul><ul><ul><ul><li>Specific query-customized pages not allowed </li></ul></ul></ul><ul><li>Create customized pages on the fly using: </li></ul><ul><ul><li>Server-side scripting </li></ul></ul><ul><ul><li>Dynamic page-generation technology </li></ul></ul>Electronic Commerce, Eighth Edition
  9. 9. Dynamic Content (cont’d.) <ul><li>Server-side scripting </li></ul><ul><ul><li>Used by first Web sites providing dynamic pages </li></ul></ul><ul><ul><li>Also called: </li></ul></ul><ul><ul><ul><li>Server-side includes </li></ul></ul></ul><ul><ul><ul><li>Server-side technologies </li></ul></ul></ul><ul><ul><li>Web server programs create Web pages before sending pages back to client </li></ul></ul><ul><ul><li>Server-side technologies are slow </li></ul></ul><ul><ul><li>Large online business Web sites alternative </li></ul></ul><ul><ul><ul><li>Dynamic page-generation technologies </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  10. 10. Dynamic Content (cont’d.) <ul><li>Dynamic page-generation technologies </li></ul><ul><ul><li>Examples </li></ul></ul><ul><ul><ul><li>Microsoft Active Server Pages (ASP) </li></ul></ul></ul><ul><ul><ul><li>Sun Microsystems JavaServer Pages (JSP) </li></ul></ul></ul><ul><ul><ul><li>Open-source Apache Software Foundation Hypertext Preprocessor (PHP) </li></ul></ul></ul><ul><ul><ul><li>Adobe Cold Fusion </li></ul></ul></ul><ul><ul><li>Dynamic Web page creation </li></ul></ul><ul><ul><ul><li>Server-side scripts mix with HTML tagged text </li></ul></ul></ul><ul><ul><li>Java servlets </li></ul></ul><ul><ul><ul><li>Server-side programs created using Java programming language (Sun) </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  11. 11. Dynamic Content (cont’d.) <ul><li>Dynamic page-generation technologies (cont’d.) </li></ul><ul><ul><li>Popular tools to generate dynamic Web pages and make them interactive </li></ul></ul><ul><ul><ul><li>AJAX (asynchronous JavaScript and XML): creates interactive Web sites looking like applications </li></ul></ul></ul><ul><ul><ul><li>Ruby on Rails: creates dynamic Web pages with interface looking like application </li></ul></ul></ul><ul><ul><ul><li>Python scripting language </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  12. 12. Dynamic Content (cont’d.) <ul><li>The future of dynamic Web page generation </li></ul><ul><ul><li>Criticisms of previous approaches </li></ul></ul><ul><ul><ul><li>Do not solve problem of dynamic page generation </li></ul></ul></ul><ul><ul><ul><li>Shift dynamic page creation from HTML coders to ASP (JSP, PHP) programmers </li></ul></ul></ul><ul><ul><li>Apache Cocoon project initiative </li></ul></ul><ul><ul><ul><li>Query XML formatted data and generate output in multiple formats </li></ul></ul></ul><ul><ul><ul><li>HTML output: useful for dynamic Web page creation </li></ul></ul></ul><ul><ul><ul><li>May apply style sheet to data: tailored response </li></ul></ul></ul><ul><ul><ul><li>Portable Document Format (PDF) file, Wireless Markup Language (WML) file </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  13. 13. Dynamic Content (cont’d.) <ul><li>The future of dynamic Web page generation (cont’d.) </li></ul><ul><ul><li>Latest Cocoon version </li></ul></ul><ul><ul><ul><li>Divides work into four areas of concern </li></ul></ul></ul><ul><ul><ul><li>Limits area interactions to five specific contracts </li></ul></ul></ul><ul><ul><ul><li>Breaks direct connection between logic and style </li></ul></ul></ul><ul><ul><ul><li>Future dynamic Web page design easier </li></ul></ul></ul><ul><ul><li>Other initiatives </li></ul></ul><ul><ul><ul><li>Microsoft: Microsoft.NET Framework </li></ul></ul></ul><ul><ul><ul><li>Oracle: including explicit PHP support (other scripting languages) in its database products </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  14. 14. Electronic Commerce, Eighth Edition
  15. 15. Various Meanings of “Server” <ul><li>Server </li></ul><ul><ul><li>Any computer providing files (programs) to other computers </li></ul></ul><ul><ul><ul><li>Connected through network </li></ul></ul></ul><ul><li>Server software </li></ul><ul><ul><li>Server computer software </li></ul></ul><ul><ul><li>Makes files (programs) available to other computers </li></ul></ul><ul><ul><li>Sometimes included with operating system </li></ul></ul><ul><li>Servers connect through router to the Internet </li></ul><ul><ul><li>Run Web server software </li></ul></ul>Electronic Commerce, Eighth Edition
  16. 16. Various Meanings of “Server” (cont’d.) <ul><li>Web servers </li></ul><ul><ul><li>Computers connected to the Internet </li></ul></ul><ul><ul><li>Run Web server software </li></ul></ul><ul><ul><ul><li>Makes server’s files available to other computers </li></ul></ul></ul><ul><li>E-mail server: handles incoming, outgoing e-mail </li></ul><ul><li>Database server </li></ul><ul><ul><li>Runs database management software </li></ul></ul><ul><li>“ Server” describes several types of computer hardware, software </li></ul><ul><ul><li>Note context </li></ul></ul>Electronic Commerce, Eighth Edition
  17. 17. Web Client/Server Communication <ul><li>Web browser requests files from Web server </li></ul><ul><ul><li>Transportation medium: the Internet </li></ul></ul><ul><ul><li>Request formatted by browser using HTTP </li></ul></ul><ul><ul><li>Request sent to server computer </li></ul></ul><ul><ul><li>Server receives request </li></ul></ul><ul><ul><ul><li>Retrieves file containing requested Web page </li></ul></ul></ul><ul><ul><ul><li>Formats using HTTP </li></ul></ul></ul><ul><ul><ul><li>Sends back to client over the Internet </li></ul></ul></ul><ul><ul><li>Client Web browser </li></ul></ul><ul><ul><ul><li>Browser displays information if it is an HTML page </li></ul></ul></ul><ul><ul><ul><li>Graphics can be slow to appear </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  18. 18. Two-Tier Client/Server Architecture <ul><li>Two-tier client/server architecture </li></ul><ul><ul><li>Messages created and read </li></ul></ul><ul><ul><ul><li>Only by client and server computers </li></ul></ul></ul><ul><li>Request message: client requesting file from server </li></ul><ul><ul><li>Request line: contains command, target resource name, protocol name, version number </li></ul></ul><ul><ul><li>Optional </li></ul></ul><ul><ul><ul><li>Request headers: file type information that client will accept </li></ul></ul></ul><ul><ul><ul><li>Entity body: passes bulk information to server </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  19. 19. Two-Tier Client/Server Architecture (cont’d.) <ul><li>Server receives request message </li></ul><ul><ul><li>Executes command included in message </li></ul></ul><ul><ul><ul><li>Retrieves file from disk </li></ul></ul></ul><ul><ul><li>Creates response message: sent back to client </li></ul></ul><ul><ul><ul><li>Identical structure as request message (slightly different function) </li></ul></ul></ul><ul><ul><ul><li>Response header line: server HTTP version, response status, status information explanation </li></ul></ul></ul><ul><ul><ul><li>Response header field: information describing server’s attributes </li></ul></ul></ul><ul><ul><ul><li>Entity body: returns HTML page requested by client (optional) </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  20. 20. Electronic Commerce, Eighth Edition
  21. 21. Three-Tier and N-Tier Client/Server Architectures <ul><li>Three-tier architecture </li></ul><ul><ul><li>Extends two-tier architecture </li></ul></ul><ul><ul><ul><li>Allows additional processing before server responds to client’s request </li></ul></ul></ul><ul><li>n-tier architectures </li></ul><ul><ul><li>Higher-order architectures; more than three tiers </li></ul></ul><ul><li>Third tier supplies information to Web server </li></ul><ul><ul><li>Databases and related software application </li></ul></ul>Electronic Commerce, Eighth Edition
  22. 22. Three-Tier and N-Tier Client/Server Architectures (cont’d.) <ul><li>Four, five (or more) tiers include: </li></ul><ul><ul><li>Software applications (like three-tier systems) </li></ul></ul><ul><ul><li>Databases, database management programs </li></ul></ul><ul><ul><ul><li>Work with software applications, generate information turned into Web pages, send to requesting client </li></ul></ul></ul><ul><li>Example: catalog-style Web site </li></ul><ul><ul><li>Search, update, display functions </li></ul></ul><ul><ul><ul><li>Track customer purchases stored in shopping carts, look up sales tax rates, keep track of customer preferences, query inventory databases, keep company catalog current </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  23. 23. Electronic Commerce, Eighth Edition
  24. 24. Software for Web Servers <ul><li>Web server software </li></ul><ul><ul><li>May run on: </li></ul></ul><ul><ul><ul><li>One or several computer operating systems </li></ul></ul></ul><ul><li>Types of Web server software/programs </li></ul><ul><ul><li>Operating system software </li></ul></ul><ul><ul><li>Web server software itself </li></ul></ul><ul><ul><li>Other programs </li></ul></ul><ul><ul><ul><li>Internet utilities </li></ul></ul></ul><ul><ul><ul><li>E-mail software </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  25. 25. Operating Systems for Web Servers <ul><li>Operating system tasks </li></ul><ul><ul><li>Running programs, allocating computer resources, providing input and output services </li></ul></ul><ul><ul><li>More responsibilities (large systems) </li></ul></ul><ul><ul><ul><li>Tracking multiple users, ensuring no interference </li></ul></ul></ul><ul><li>Microsoft Windows Server products </li></ul><ul><ul><li>Considered simple to learn and use </li></ul></ul><ul><ul><li>Raise security concerns </li></ul></ul><ul><li>Linux-, UNIX-based products </li></ul><ul><ul><li>Popular </li></ul></ul><ul><ul><li>Considered secure as Web servers </li></ul></ul>Electronic Commerce, Eighth Edition
  26. 26. Operating Systems for Web Servers (cont’d.) <ul><li>Linux (open-source operating system) </li></ul><ul><ul><li>Fast, efficient, installs easily </li></ul></ul><ul><ul><li>Open-source software </li></ul></ul><ul><ul><ul><li>Developed by community of programmers </li></ul></ul></ul><ul><ul><ul><li>Software available for download (free) </li></ul></ul></ul><ul><ul><ul><li>Others use it, improve it, submit improved versions </li></ul></ul></ul><ul><li>More information </li></ul><ul><ul><li>Open Source Initiative Web site </li></ul></ul>Electronic Commerce, Eighth Edition
  27. 27. Operating Systems for Web Servers (cont’d.) <ul><li>Companies selling Web server computers </li></ul><ul><ul><li>Include Linux in default configurations </li></ul></ul><ul><li>Companies may buy Linux through commercial distributors </li></ul><ul><ul><li>Include useful additional software (installation utilities) </li></ul></ul><ul><ul><li>Provide support contracts </li></ul></ul><ul><ul><li>Examples: Mandriva, Red Hat, SCO Group, SuSE </li></ul></ul><ul><li>Sun Microsystems </li></ul><ul><ul><li>Sells Web server hardware </li></ul></ul><ul><ul><li>Solaris : UNIX-based operating system </li></ul></ul>Electronic Commerce, Eighth Edition
  28. 28. Web Server Software <ul><li>Commonly used Web server programs </li></ul><ul><ul><li>Apache HTTP Server, Microsoft Internet Information Server (IIS), Sun Java System Web Server (JSWS) </li></ul></ul><ul><li>Netcraft networking consulting company Web survey </li></ul><ul><ul><li>Measures Web server software’s relative popularity </li></ul></ul><ul><ul><ul><li>Stabilizing in recent years </li></ul></ul></ul><ul><ul><li>See Figure 8.5 </li></ul></ul><ul><li>Web server performance differences </li></ul><ul><ul><li>Workload, operating system, Web pages served </li></ul></ul><ul><ul><ul><li>Critical: choose right server for each business need </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  29. 29. Electronic Commerce, Eighth Edition
  30. 30. Web Server Software (cont’d.) <ul><li>Apache HTTP Server </li></ul><ul><ul><li>1994: Rob McCool developed Apache </li></ul></ul><ul><ul><li>Original core system with lots of patches </li></ul></ul><ul><ul><ul><li>Known as “a patchy” server </li></ul></ul></ul><ul><ul><li>Ongoing group software development effort </li></ul></ul><ul><ul><li>Dominated Web since 1996 </li></ul></ul><ul><ul><ul><li>Free, performs efficiently </li></ul></ul></ul><ul><ul><li>In IBM WebSphere application server package </li></ul></ul><ul><ul><li>Zeus based on Apache open-source code </li></ul></ul><ul><ul><li>Most widely installed Web server software package </li></ul></ul><ul><ul><li>Runs on many operating systems, hardware </li></ul></ul>Electronic Commerce, Eighth Edition
  31. 31. Web Server Software (cont’d.) <ul><li>Microsoft Internet Information Server </li></ul><ul><ul><li>Bundled with Microsoft Windows Server operating systems </li></ul></ul><ul><ul><ul><li>Runs on Windows server operating system (by design) </li></ul></ul></ul><ul><ul><li>Used on many corporate intranets </li></ul></ul><ul><ul><ul><li>Adopted Microsoft products as standard products </li></ul></ul></ul><ul><ul><li>ASP, ActiveX Data Objects, SQL database queries </li></ul></ul><ul><ul><li>Microsoft FrontPage Web site development tool, reporting tools </li></ul></ul><ul><ul><li>HTML pages, ActiveX components, scripts can be combined to produce dynamic Web pages </li></ul></ul>Electronic Commerce, Eighth Edition
  32. 32. Web Server Software (cont’d.) <ul><li>Sun Java System Web Server (Sun ONE, iPlanet, Netscape) </li></ul><ul><ul><li>Original NCSA Web server program descendent </li></ul></ul><ul><ul><li>Former names: Sun ONE, Netscape Enterprise Server, iPlanet Enterprise Server </li></ul></ul><ul><ul><li>AOL-Sun Microsystems partnership called iPlanet </li></ul></ul><ul><ul><ul><li>Agreement expired March 2002 </li></ul></ul></ul><ul><ul><ul><li>iPlanet became part of Sun </li></ul></ul></ul><ul><ul><li>Not free: reasonable licensing fee </li></ul></ul><ul><ul><li>Runs on many operating systems </li></ul></ul>Electronic Commerce, Eighth Edition
  33. 33. Web Server Software (cont’d.) <ul><li>Sun Java System Web Server (Sun ONE, iPlanet, Netscape) (cont’d.) </li></ul><ul><ul><li>Web server use </li></ul></ul><ul><ul><ul><li>One percent of all Web servers </li></ul></ul></ul><ul><ul><ul><li>Busiest and best-known Internet sites: BMW, Dilbert, E*TRADE, Excite, Lycos, Schwab </li></ul></ul></ul><ul><ul><ul><li>More than 30 percent of all public Web sites </li></ul></ul></ul><ul><ul><ul><li>More than half of top 100 enterprise Web sites </li></ul></ul></ul><ul><ul><li>Supports dynamic application development </li></ul></ul><ul><ul><li>Provides connectivity to database products </li></ul></ul>Electronic Commerce, Eighth Edition
  34. 34. Finding Web Server Software Information <ul><li>The Netcraft Web site home page </li></ul><ul><ul><li>“ What’s that site running?” link </li></ul></ul><ul><ul><ul><li>Leads to page with search function </li></ul></ul></ul><ul><ul><ul><li>Find out operating system, Web server software specific site now running </li></ul></ul></ul><ul><ul><ul><li>Find out what site ran in the past </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  35. 35. Electronic Mail (E-Mail) <ul><li>Electronic commerce important technologies </li></ul><ul><ul><li>Web: interactions between Web servers and clients </li></ul></ul><ul><ul><li>E-mail </li></ul></ul><ul><ul><ul><li>Gather information, execute transactions, perform other electronic commerce-related tasks </li></ul></ul></ul><ul><ul><ul><li>1970s origin: ARPANET </li></ul></ul></ul><ul><ul><ul><li>Most popular form of business communication </li></ul></ul></ul><ul><ul><ul><li>Far surpassing: telephone, conventional mail, fax (in volume) </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  36. 36. E-Mail Benefits <ul><li>Reason many people attracted to the Internet </li></ul><ul><li>Conveys messages in seconds </li></ul><ul><ul><li>Simple ASCII text, character formatting </li></ul></ul><ul><li>Useful e-mail feature </li></ul><ul><ul><li>Attachments: most important message part </li></ul></ul><ul><li>E-mail uses </li></ul><ul><ul><li>Confirm receipt of customer orders, confirm shipment of items ordered, send information about a purchase to buyer, announce specials and sales, keep in touch with customers </li></ul></ul>Electronic Commerce, Eighth Edition
  37. 37. E-Mail Drawbacks <ul><li>Time spent answering e-mail </li></ul><ul><ul><li>Managers: five minutes per e-mail </li></ul></ul><ul><ul><li>Average person spends two hours a day </li></ul></ul><ul><ul><li>Creating resentment </li></ul></ul><ul><li>Computer virus (through attachments) </li></ul><ul><ul><li>Program attaches itself to another program </li></ul></ul><ul><ul><ul><li>Causes damage when host program activated </li></ul></ul></ul><ul><ul><li>Cost for e-mail convenience </li></ul></ul><ul><ul><ul><li>Virus protection software, dealing with security threats </li></ul></ul></ul><ul><li>Spam (unsolicited commercial e-mail) </li></ul><ul><ul><li>Most frustrating and expensive e-mail problem </li></ul></ul>Electronic Commerce, Eighth Edition
  38. 38. Spam <ul><li>Magnitude of spam problem </li></ul><ul><ul><li>24-hour period in 2008 </li></ul></ul><ul><ul><ul><li>220 billion spam e-mail messages sent </li></ul></ul></ul><ul><ul><li>Researchers believe: </li></ul></ul><ul><ul><ul><li>More than 98 percent of all e-mail messages will be spam before effective technical solutions implemented </li></ul></ul></ul><ul><ul><ul><li>Spam leveling off (approaching 100 percent) </li></ul></ul></ul><ul><ul><li>Absolute spam e-mail numbers could continue to grow rapidly </li></ul></ul>Electronic Commerce, Eighth Edition
  39. 39. Electronic Commerce, Eighth Edition
  40. 40. Spam (cont’d.) <ul><li>AOL active has taken active role limiting spam through legal channels </li></ul><ul><ul><li>2005: temporary decline </li></ul></ul><ul><ul><li>Now: resumed increase </li></ul></ul><ul><li>Antispam efforts </li></ul><ul><ul><li>Limit spam annoyance and cost </li></ul></ul><ul><ul><li>E-mail server computer software </li></ul></ul><ul><ul><ul><li>Limit amount of spam getting through to employees </li></ul></ul></ul><ul><ul><li>Individual users </li></ul></ul><ul><ul><ul><li>Install client-based spam-filtering programs, set filters </li></ul></ul></ul><ul><li>More effective, less costly to eliminate spam before downloaded </li></ul>Electronic Commerce, Eighth Edition
  41. 41. Solutions to the Spam Problem <ul><li>Some solutions require: </li></ul><ul><ul><li>Passing of new laws </li></ul></ul><ul><ul><li>Technical changes in Internet mail-handling systems </li></ul></ul><ul><li>Other approaches </li></ul><ul><ul><li>Implemented with existing laws and current technologies </li></ul></ul><ul><ul><ul><li>Requires cooperation from large numbers of organizations and businesses </li></ul></ul></ul><ul><li>Individual e-mail users </li></ul><ul><ul><li>Few tactics available to reduce spam </li></ul></ul>Electronic Commerce, Eighth Edition
  42. 42. Solutions to the Spam Problem (cont’d.) <ul><li>Individual user antispam tactics </li></ul><ul><ul><li>Focus </li></ul></ul><ul><ul><ul><li>Limit spammer’s access to (use of) e-mail address </li></ul></ul></ul><ul><ul><li>Use complex e-mail address </li></ul></ul><ul><ul><ul><li>[email_address] </li></ul></ul></ul><ul><ul><li>Control e-mail address exposure; software robots </li></ul></ul><ul><ul><ul><li>Discussion boards, chat rooms, other online sources </li></ul></ul></ul><ul><ul><li>Use multiple e-mail addresses </li></ul></ul><ul><ul><ul><li>Switch to another if spammers uses one </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  43. 43. Solutions to the Spam Problem (cont’d.) <ul><li>Basic content filtering </li></ul><ul><ul><li>Requires software </li></ul></ul><ul><ul><ul><li>Identifies content elements in incoming e-mail message </li></ul></ul></ul><ul><ul><li>Content-filtering techniques differ in terms of: </li></ul></ul><ul><ul><ul><li>Content elements examined </li></ul></ul></ul><ul><ul><ul><li>Looking for message spam indications </li></ul></ul></ul><ul><ul><ul><li>How strictly message classification rules applied </li></ul></ul></ul><ul><ul><li>Basic content filters examine e-mail headers </li></ul></ul><ul><ul><li>Filtering task software location </li></ul></ul><ul><ul><ul><li>Client-level filtering: individual users’ computers </li></ul></ul></ul><ul><ul><ul><li>Server-level filtering: mail server computers </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  44. 44. Solutions to the Spam Problem (cont’d.) <ul><li>Basic content filtering (cont’d.) </li></ul><ul><ul><li>Black list spam filter </li></ul></ul><ul><ul><ul><li>Looks for known spammers From addresses in incoming messages </li></ul></ul></ul><ul><ul><li>White list spam filter </li></ul></ul><ul><ul><ul><li>Looks for good sender From addresses in incoming messages </li></ul></ul></ul><ul><ul><ul><li>High false positives rate: messages rejected (should not have been) </li></ul></ul></ul><ul><ul><li>Used in client-level or server-level filters </li></ul></ul><ul><ul><ul><li>Overcome individual drawbacks: use approaches together with other content-filtering approaches </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  45. 45. Solutions to the Spam Problem (cont’d.) <ul><li>Challenge-response content filtering </li></ul><ul><ul><li>Compares all incoming messages to a white list </li></ul></ul><ul><ul><ul><li>If sender not on white list, automated e-mail response sent (challenge) </li></ul></ul></ul><ul><ul><ul><li>Challenge asks sender to reply to e-mail (response) </li></ul></ul></ul><ul><ul><ul><li>Reply must contain response to a challenge presented in the e-mail </li></ul></ul></ul><ul><ul><li>Designed so human can respond easily </li></ul></ul><ul><ul><li>Drawbacks </li></ul></ul><ul><ul><ul><li>Victim bombarded; perpetrator includes victim’s e-mail </li></ul></ul></ul><ul><ul><ul><li>Doubles amount of useless e-mail messages sent </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  46. 46. Solutions to the Spam Problem (cont’d.) <ul><li>Advanced content filtering </li></ul><ul><ul><li>Uses indicators </li></ul></ul><ul><ul><ul><li>Words, word pairs, certain HTML codes, information about where word occurs </li></ul></ul></ul><ul><ul><li>Looks for spam indicators (entire e-mail message) </li></ul></ul><ul><ul><ul><li>Indicator identified; message’s spam “score” raised </li></ul></ul></ul><ul><ul><li>Problems </li></ul></ul><ul><ul><ul><li>Spammers stop including defined indicators </li></ul></ul></ul><ul><ul><ul><li>Challenge creating effective content filters </li></ul></ul></ul><ul><ul><ul><li>Filtering “sex” may delete valid e-mail with “Essex” </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  47. 47. Solutions to the Spam Problem (cont’d.) <ul><li>Advanced content filtering (cont’d.) </li></ul><ul><ul><li>Approach based on branch of applied mathematics </li></ul></ul><ul><ul><ul><li>Bayesian statistics </li></ul></ul></ul><ul><ul><li>Bayesian revision statistical technique </li></ul></ul><ul><ul><ul><li>Additional knowledge used to revise earlier probability estimates </li></ul></ul></ul><ul><ul><li>Naïve Bayesian filter </li></ul></ul><ul><ul><ul><li>Software begins by not classifying messages </li></ul></ul></ul><ul><ul><ul><li>User reviews messages </li></ul></ul></ul><ul><ul><ul><li>Message type indicated to software: spam (not spam) </li></ul></ul></ul><ul><ul><ul><li>Software gradually learns message element </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  48. 48. Solutions to the Spam Problem (cont’d.) <ul><li>Advanced content filtering (cont’d.) </li></ul><ul><ul><li>Naïve Bayesian filter success rates </li></ul></ul><ul><ul><ul><li>Few dozen messages classified: 80 percent effective </li></ul></ul></ul><ul><ul><ul><li>Eventually: effective rate rises above 95 percent </li></ul></ul></ul><ul><ul><li>2002: POPFile released </li></ul></ul><ul><ul><ul><li>First functional Bayesian filter product for individuals </li></ul></ul></ul><ul><ul><ul><li>Open-source software development project </li></ul></ul></ul><ul><ul><ul><li>Installs on individual client computers </li></ul></ul></ul><ul><ul><ul><li>Works with many different e-mail clients: Post Office Protocol (POP) connection required </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  49. 49. Electronic Commerce, Eighth Edition
  50. 50. Solutions to the Spam Problem (cont’d.) <ul><li>Advanced content filtering (cont’d.) </li></ul><ul><ul><li>POPFile success </li></ul></ul><ul><ul><ul><li>Initially caught 30 percent of spam messages </li></ul></ul></ul><ul><ul><ul><li>After two weeks: caught more than 90 percent </li></ul></ul></ul><ul><ul><ul><li>Eventually: caught more than 99 percent </li></ul></ul></ul><ul><ul><ul><li>False positives: small rate </li></ul></ul></ul><ul><ul><li>POPFile magnet feature </li></ul></ul><ul><ul><ul><li>Implement white and black list filtering </li></ul></ul></ul><ul><ul><li>Naïve Bayesian filters’ effectiveness </li></ul></ul><ul><ul><ul><li>Very effective client-level filters </li></ul></ul></ul><ul><ul><ul><li>Major drawback: users must update filters regularly </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  51. 51. Electronic Commerce, Eighth Edition
  52. 52. Solutions to the Spam Problem (cont’d.) <ul><li>Legal solutions </li></ul><ul><ul><li>January 2004: U.S. CAN-SPAM law went into effect </li></ul></ul><ul><ul><li>Spammers slowed down activities immediately </li></ul></ul><ul><ul><li>Seeing no threat of broad federal prosecution: </li></ul></ul><ul><ul><ul><li>Spam rates increased </li></ul></ul></ul><ul><ul><ul><li>Spam estimate: over 80 percent of all e-mail messages </li></ul></ul></ul><ul><ul><li>CAN-SPAM </li></ul></ul><ul><ul><ul><li>Regulates all e-mail messages </li></ul></ul></ul><ul><ul><ul><li>Regulates messages advertising or promoting commercial product or service </li></ul></ul></ul><ul><ul><ul><li>Includes messages promoting Web site content </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  53. 53. Solutions to the Spam Problem (cont’d.) <ul><li>Legal solutions (cont’d.) </li></ul><ul><ul><li>CAN-SPAM (cont’d.) </li></ul></ul><ul><ul><ul><li>Prohibits misleading e-mail message address header information, facilitating agreed-upon transaction or updating customer in existing business relationship </li></ul></ul></ul><ul><ul><ul><li>Successful prosecution: fines ($11,000) and imprisonment </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  54. 54. Solutions to the Spam Problem (cont’d.) <ul><li>Legal solutions (cont’d.) </li></ul><ul><ul><li>More information </li></ul></ul><ul><ul><ul><li>U.S. Federal Trade Commission CAN-SPAM Law information pages </li></ul></ul></ul><ul><ul><li>Few spammers prosecuted under the law </li></ul></ul><ul><ul><ul><li>December 2003 verdict: three spammers pay more than $1 billion </li></ul></ul></ul><ul><ul><ul><li>2005 Jeremy Jaynes conviction: nine years in prison (appeal rejected) </li></ul></ul></ul><ul><ul><li>FTC refused to create do-not-spam list </li></ul></ul>Electronic Commerce, Eighth Edition
  55. 55. Solutions to the Spam Problem (cont’d.) <ul><li>Legal solutions (cont’d.) </li></ul><ul><ul><li>CAN-SPAM (similar laws) ineffectiveness </li></ul></ul><ul><ul><ul><li>Spammers have been violating laws for years </li></ul></ul></ul><ul><ul><ul><li>Mail servers located in other countries; jurisdiction unclear </li></ul></ul></ul><ul><ul><ul><li>Fines or collection of damages difficult to obtain </li></ul></ul></ul><ul><ul><ul><li>Spammers evade cease-and-desist orders; move operations from one server to another (in minutes) </li></ul></ul></ul><ul><ul><ul><li>Spammers hijack servers to forward mail </li></ul></ul></ul><ul><ul><li>Hope is that CAN-SPAM and similar laws enforce constraints on legitimate marketers </li></ul></ul>Electronic Commerce, Eighth Edition
  56. 56. Solutions to the Spam Problem (cont’d.) <ul><li>Legal solutions (cont’d.) </li></ul><ul><ul><li>Legal solution; critics’ arguments </li></ul></ul><ul><ul><ul><li>Failure until spammer prosecution becomes cost effective for governments </li></ul></ul></ul><ul><ul><li>Cost effective when: </li></ul></ul><ul><ul><ul><li>Prosecutors able to identify spammers easily </li></ul></ul></ul><ul><ul><ul><li>Greater likelihood of winning cases </li></ul></ul></ul><ul><ul><li>Best way to make spammers easier to find </li></ul></ul><ul><ul><ul><li>Make technical changes in the e-mail transport mechanism </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  57. 57. Solutions to the Spam Problem (cont’d.) <ul><li>Technical solutions </li></ul><ul><ul><li>Internet design not intended for today's needs </li></ul></ul><ul><ul><ul><li>E-mail: incidental afterthought </li></ul></ul></ul><ul><ul><ul><li>No mechanisms ensuring e-mail sender identity </li></ul></ul></ul><ul><ul><li>Internet’s polite set of rules </li></ul></ul><ul><ul><ul><li>Send and wait for acknowledgement (fast) </li></ul></ul></ul><ul><ul><li>Slowing down acknowledgment messages </li></ul></ul><ul><ul><ul><li>Originating computer will slow (must continue to scan for acknowledgment) </li></ul></ul></ul><ul><ul><ul><li>Will not send more messages (to that address) until acknowledgment received </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  58. 58. Solutions to the Spam Problem (cont’d.) <ul><li>Technical solutions (cont’d.) </li></ul><ul><ul><li>Slowing down acknowledgment messages (cont’d.) </li></ul></ul><ul><ul><ul><li>Requires defending company to develop way to identify computers sending spam </li></ul></ul></ul><ul><ul><li>IBM software: access to large database tracking such computers </li></ul></ul><ul><ul><li>Other vendors: software identifying multiple e-mail messages from single source in rapid succession </li></ul></ul><ul><ul><li>Once identified: software delays sending message acknowledgment </li></ul></ul>Electronic Commerce, Eighth Edition
  59. 59. Solutions to the Spam Problem (cont’d.) <ul><li>Technical solutions (cont’d.) </li></ul><ul><ul><li>Teergrubing: launching a return attack </li></ul></ul><ul><ul><ul><li>Sending e-mail messages back to computer originating suspected spam </li></ul></ul></ul><ul><ul><li>Teergrubing objective </li></ul></ul><ul><ul><ul><li>Ensure computer sending spam is trapped </li></ul></ul></ul><ul><ul><ul><li>Drag down ability to send spam </li></ul></ul></ul><ul><ul><ul><li>Concern: counterattack might violate laws </li></ul></ul></ul><ul><ul><li>Ultimate spam problem </li></ul></ul><ul><ul><ul><li>New e-mail protocols providing absolute verification of e-mail message source </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  60. 60. Web Site and Internet Utility Programs <ul><li>TCP/IP supports utility programs (tools) </li></ul><ul><ul><li>Run on Web server or client computers </li></ul></ul><ul><li>Earliest Internet utility program </li></ul><ul><ul><li>E-mail </li></ul></ul><ul><ul><ul><li>Most important utility </li></ul></ul></ul><ul><ul><ul><li>Key element in electronic commerce strategies </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  61. 61. Finger and Ping Utilities <ul><li>Finger program </li></ul><ul><ul><li>Runs on UNIX operating systems </li></ul></ul><ul><ul><li>Provides information about other network users </li></ul></ul><ul><ul><li>Many organizations disable Finger command </li></ul></ul><ul><ul><ul><li>Privacy and security </li></ul></ul></ul><ul><ul><li>Built into some e-mail programs </li></ul></ul><ul><li>Ping: Packet Internet Groper </li></ul><ul><ul><li>Tests connectivity between two Internet-connected computers </li></ul></ul><ul><ul><li>Provides performance data about connection </li></ul></ul><ul><ul><li>Available as freeware and shareware </li></ul></ul>Electronic Commerce, Eighth Edition
  62. 62. Tracert and Other Route-Tracing Programs <ul><li>Tracert (TRACE RouTe) </li></ul><ul><ul><li>Sends data packets to every computer on path </li></ul></ul><ul><ul><ul><li>Between one computer and another computer </li></ul></ul></ul><ul><ul><li>Clocks packets’ round-trip times </li></ul></ul><ul><ul><li>Provides indication of time message needs to travel from one computer to another and back </li></ul></ul><ul><ul><li>Ensures remote computer online </li></ul></ul><ul><ul><li>Pinpoints data traffic congestion </li></ul></ul><ul><ul><li>Calculates and displays: </li></ul></ul><ul><ul><ul><li>Number of hops between computers </li></ul></ul></ul><ul><ul><ul><li>Time to traverse entire one-way path </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  63. 63. Tracert and Other Route-Tracing Programs (cont’d.) <ul><li>Tracert (cont’d.) </li></ul><ul><ul><li>Sends series of packets to particular destination </li></ul></ul><ul><ul><li>Router along Internet path between originating and destination computers: </li></ul></ul><ul><ul><ul><li>Reports IP address and time packet arrived </li></ul></ul></ul><ul><ul><li>Graphical user interface route-tracing programs: </li></ul></ul><ul><ul><ul><li>Provides map plot of packets’ route </li></ul></ul></ul><ul><ul><li>Determines Internet locations with greatest delay </li></ul></ul><ul><ul><li>Example </li></ul></ul><ul><ul><ul><li>Visualware VisualRoute route-tracing program </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  64. 64. Electronic Commerce, Eighth Edition
  65. 65. Telnet and FTP Utilities <ul><li>Telnet program: users log on to Internet-connected computer </li></ul><ul><ul><li>Useful if no Web interface </li></ul></ul><ul><ul><li>Availability </li></ul></ul><ul><ul><ul><li>Free Internet downloads: Microsoft Telnet.exe </li></ul></ul></ul><ul><ul><li>Client computer gives commands to remote host programs </li></ul></ul><ul><ul><li>Telnet protocol: set of rules used by Telnet program </li></ul></ul><ul><ul><li>Web browser Telnet client </li></ul></ul><ul><ul><ul><li>“ telnet://” followed by remote host domain name </li></ul></ul></ul><ul><ul><li>Telnet use decreasing </li></ul></ul>Electronic Commerce, Eighth Edition
  66. 66. Telnet and FTP Utilities (cont’d.) <ul><li>File Transfer Protocol (FTP) </li></ul><ul><ul><li>TCP/IP rules defining formats </li></ul></ul><ul><ul><ul><li>Transfer files between TCP/IP-connected computers </li></ul></ul></ul><ul><ul><li>Useful services </li></ul></ul><ul><ul><ul><li>Displaying remote, local computers’ directories </li></ul></ul></ul><ul><ul><ul><li>Changing current client’s or server’s active directory </li></ul></ul></ul><ul><ul><ul><li>Creating and removing local and remote directories </li></ul></ul></ul><ul><ul><li>Uses TCP and its built-in error controls: </li></ul></ul><ul><ul><ul><li>To copy files accurately </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  67. 67. Telnet and FTP Utilities (cont’d.) <ul><li>FTP remote computer access </li></ul><ul><ul><li>FTP client program or browser </li></ul></ul><ul><ul><li>Protocol name (ftp://) before remote computer domain name </li></ul></ul><ul><li>Full-privilege FTP </li></ul><ul><ul><li>FTP connection to computer; user has account </li></ul></ul><ul><li>Anonymous FTP </li></ul><ul><ul><li>Guest account </li></ul></ul><ul><ul><ul><li>Username: “anonymous” </li></ul></ul></ul><ul><ul><ul><li>Password: e-mail address </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  68. 68. Indexing and Searching Utility Programs <ul><li>Search engines (search tools) </li></ul><ul><ul><li>Search for requested documents </li></ul></ul><ul><ul><ul><li>Specific site or entire Web </li></ul></ul></ul><ul><li>Indexing program </li></ul><ul><ul><li>Provides full-text indexing </li></ul></ul><ul><li>Browser search methods </li></ul><ul><ul><li>Compare index terms to requester’s search term </li></ul></ul><ul><ul><li>Use complex relevance ranking rules </li></ul></ul><ul><ul><ul><li>Advanced search engine software (Google) </li></ul></ul></ul><ul><li>Web server software contains indexing software </li></ul>Electronic Commerce, Eighth Edition
  69. 69. Data Analysis Software <ul><li>Web servers capture visitor information </li></ul><ul><ul><li>Placed into Web log file (grows quickly) </li></ul></ul><ul><li>Third-party Web log file analysis programs </li></ul><ul><ul><li>Summarize log file information </li></ul></ul><ul><ul><ul><li>Query log file </li></ul></ul></ul><ul><ul><ul><li>Return gross summary information or accumulating details </li></ul></ul></ul><ul><li>Popular Web log file analysis programs </li></ul><ul><ul><li>Omniture, UrchinWeb Analytics, Web Side Story, WebTrends products </li></ul></ul>Electronic Commerce, Eighth Edition
  70. 70. Link-Checking Utilities <ul><li>Link checker </li></ul><ul><ul><li>Examines each site page </li></ul></ul><ul><ul><ul><li>Reports broken, incorrect URLs </li></ul></ul></ul><ul><ul><li>Identifies orphan files </li></ul></ul><ul><ul><ul><li>Web site file not linked to a page </li></ul></ul></ul><ul><ul><li>Script checking and HTML validation </li></ul></ul><ul><li>Dead link </li></ul><ul><ul><li>When clicked: </li></ul></ul><ul><ul><ul><li>Displays error message rather than Web page </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  71. 71. Link-Checking Utilities (cont’d.) <ul><li>Link-checking programs </li></ul><ul><ul><li>Adobe Dreamweaver, Elsop LinkScan </li></ul></ul><ul><li>Reverse link checker </li></ul><ul><ul><li>Checks company’s link exchange program sites </li></ul></ul><ul><ul><li>Ensures link exchange partners fulfilling obligation </li></ul></ul><ul><ul><ul><li>Include link back to company’s Web site </li></ul></ul></ul><ul><ul><li>Example: LinxCop </li></ul></ul>Electronic Commerce, Eighth Edition
  72. 72. Remote Server Administration <ul><li>Remote server administration </li></ul><ul><ul><li>Web site administrator controls Web site </li></ul></ul><ul><ul><ul><li>From any Internet-connected computer </li></ul></ul></ul><ul><ul><li>Provides convenience </li></ul></ul><ul><ul><li>Examples </li></ul></ul><ul><ul><ul><li>Website Garage </li></ul></ul></ul><ul><ul><ul><li>NetMechanic </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  73. 73. Web Server Hardware <ul><li>Hosting electronic commerce operations </li></ul><ul><ul><li>Use wide variety of computer brands, types, sizes </li></ul></ul><ul><ul><li>Some small companies run Web sites on desktop PCs </li></ul></ul><ul><ul><li>Most Web sites operated on computers </li></ul></ul><ul><ul><ul><li>Designed for site hosting </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  74. 74. Server Computers <ul><li>Use more capable hardware elements </li></ul><ul><ul><li>Usually more expensive than workstation PCs </li></ul></ul><ul><li>Price range of Web server computer </li></ul><ul><ul><li>Between $3000 and $200,000 </li></ul></ul><ul><li>Companies selling Web server hardware </li></ul><ul><ul><li>Provide Web site configuration tools </li></ul></ul><ul><ul><ul><li>Visitors design their own Web server </li></ul></ul></ul><ul><li>Housing Web server computers </li></ul><ul><ul><li>Freestanding cases </li></ul></ul><ul><ul><li>Installed in equipment racks </li></ul></ul>Electronic Commerce, Eighth Edition
  75. 75. Electronic Commerce, Eighth Edition
  76. 76. Server Computers (cont’d.) <ul><li>Blade servers: servers-on-a-card </li></ul><ul><ul><li>Small: 300 installed in single 6-foot rack </li></ul></ul><ul><li>Fundamental Web server job </li></ul><ul><ul><li>Process and respond to Web client requests </li></ul></ul><ul><ul><ul><li>Sent using HTTP </li></ul></ul></ul><ul><li>Virtual server ( virtual host ) </li></ul><ul><ul><li>Maintains more than one server on one machine </li></ul></ul><ul><ul><li>Different groups have separate domain names </li></ul></ul><ul><ul><ul><li>All domain names refer to same physical Web server </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  77. 77. Web Server Performance Evaluation <ul><li>Benchmarking: testing to compare hardware and software performance </li></ul><ul><li>Elements affecting overall server performance </li></ul><ul><ul><li>Hardware, operating system software, server software, connection speed, user capacity, type of Web pages being delivered </li></ul></ul><ul><ul><li>Connection speed (T3 faster than T1) </li></ul></ul><ul><ul><li>Number of users server can handle </li></ul></ul><ul><ul><ul><li>Important </li></ul></ul></ul><ul><ul><ul><li>Hard to measure </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  78. 78. Web Server Performance Evaluation (cont’d.) <ul><li>Throughput: number of HTTP requests hardware and software combination can process </li></ul><ul><ul><li>Unit of time </li></ul></ul><ul><li>Response time: time that server requires to process one request </li></ul><ul><li>Choosing Web server hardware configurations </li></ul><ul><ul><li>Run tests on various combinations, consider scalability, compare standard benchmarks </li></ul></ul><ul><ul><li>Use independent testing labs: Mindcraft </li></ul></ul><ul><li>Run benchmarks regularly </li></ul><ul><li>Provide site visitors with best service possible </li></ul>Electronic Commerce, Eighth Edition
  79. 79. Web Server Hardware Architectures <ul><li>Electronic commerce Web sites use tiered architecture </li></ul><ul><ul><li>Divides work of serving Web pages </li></ul></ul><ul><ul><li>May use more than one computer within each tier </li></ul></ul><ul><li>Server farms: large collections of servers </li></ul><ul><ul><li>Lined up row after row </li></ul></ul><ul><li>Centralized architecture </li></ul><ul><ul><li>Uses a few large and fast computers </li></ul></ul><ul><ul><ul><li>Requires expensive computers </li></ul></ul></ul><ul><ul><ul><li>More sensitive to technical problems </li></ul></ul></ul><ul><ul><ul><li>Requires adequate backup plans </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  80. 80. Web Server Hardware Architectures (cont’d.) <ul><li>Distributed architecture ( decentralized architecture ) </li></ul><ul><ul><li>Uses a large number of less powerful computers </li></ul></ul><ul><ul><ul><li>Spreads risk over large number of servers </li></ul></ul></ul><ul><ul><ul><li>Servers are less expensive </li></ul></ul></ul><ul><ul><ul><li>Requires additional hubs or switches to connect servers to each and the Internet </li></ul></ul></ul><ul><ul><ul><li>Requires cost of load balancing </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  81. 81. Web Server Hardware Architectures (cont’d.) <ul><li>Load-balancing systems ($5000 - $50,000) </li></ul><ul><ul><li>Network hardware monitoring; server workloads </li></ul></ul><ul><ul><ul><li>Assigns incoming Web traffic to server with most available capacity </li></ul></ul></ul><ul><ul><li>Simple load-balancing system </li></ul></ul><ul><ul><ul><li>Traffic enters through site’s router </li></ul></ul></ul><ul><ul><ul><li>Encounters load-balancing switch </li></ul></ul></ul><ul><ul><ul><li>Directs traffic to best Web server </li></ul></ul></ul><ul><ul><li>More complex load-balancing systems </li></ul></ul><ul><ul><ul><li>Incoming Web traffic enters from two or more routers </li></ul></ul></ul><ul><ul><ul><li>Directed to groups of dedicated Web server </li></ul></ul></ul>Electronic Commerce, Eighth Edition
  82. 82. Electronic Commerce, Eighth Edition
  83. 83. Electronic Commerce, Eighth Edition
  84. 84. Summary <ul><li>Client/server Web architecture </li></ul><ul><ul><li>HTTP-based tiered architectures </li></ul></ul><ul><li>Operating systems commonly used on Web servers </li></ul><ul><li>Web server utility programs </li></ul><ul><ul><li>E-mail benefits and drawbacks </li></ul></ul><ul><ul><ul><li>Spam description and solutions </li></ul></ul></ul><ul><li>Web server hardware </li></ul><ul><ul><li>Important consideration in online business site design </li></ul></ul><ul><li>Web server performance </li></ul><ul><ul><li>Factors and solutions </li></ul></ul>Electronic Commerce, Eighth Edition

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