According to the META Group, a major focus of application de-livery for the next two years will be to support specific extended enterprise requirements. These extended enterprise requirements include intranets and extranets, which are built on standards set for the World Wide Web. The META Group predicts that intranet applications will predominantly utilize the three-tier model, while extranet applications will require models with four or more tiers. The implication is that big business is taking the Internet seriously.
Web models are becoming a popular way to distribute applications.
The World Wide Web is technically an Internet client/server hypertext-distributed information system. You might view it as a very large multimedia client/server network. The browser (the client) downloads remote text and graphics files from a server to the local computer and then displays them on the local com-puter’s screen. The text file is written using Hypertext Markup Language (HTML), which the local computer translates for display along with graphics files and any scripts that have been downloaded. The speed of this process depends on a number of factors:
HTML pages are downloaded from networked servers and translated by the browser.
The speed with which a system displays the graphics also depends in part on the power of the workstation. Much like the two-tier and three-tier client/server models, some of the computing burden still resides on the client. Quite frankly, Internet browsers utilize quite a bit of a system’s resources.
IS professionals can provide information and applications using the Web paradigm—with the browser client accessing data from a server with HTML pages via the Internet, the intranet, or the extranet. You might ask, “What’s the difference between these three? Aren’t these just buzzwords made up by marketing professionals to ensure that they make their review objectives and get their bonuses and yearly portion of stock options?” Well, that’s not quite the answer. While all three require use of an Internet browser to access data distributed by Web-based servers, the intended audience and security differs in each case, as the following table shows.