What is a Web/Portal Server?

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Fundamentally, an application server connects database information (from a database server) to the end-user or client program (typically a Web browser). However, there is a need for having an intermediate player in this connection. This player is the Web/Portal server also referred to as a Web Application Server (WAS) and its role is to fulfill the following needs:

• decrease the size and complexity of client programs
  
• cache and control the data flow for better performance
  
• provide security for both data and user traffic
  
• provide a distribution method for data
  

This function of an application server occupies a space between the database server and the end user commonly referred to as “middleware”.

Application servers first appeared in client/server computing and on LANs. At first, they were often associated with "tiered" applications, when people described the functionality of applications as two-tiered (database and client program), three-tiered (database, client program, and application server), or n-tiered (all of the above plus something else or “some number of tiers”). N-tier application structure implies the client/server program model. When there are more than three distribution levels or tiers involved, the additional tiers in the application are usually associated with the business logic tier.

This is a complex model of application development that is now present on the World Wide Web. The Web can be three-tiered as well as n-tiered and as such the application server has evolved into what is now referred to as a Web Application Server.

Parallel Crystal is used in the n-tiered model of application development. Where tier one represents the end user making a request from an internet browser. Tier two represents the web application server that among many things controls: the data flow, security, and distribution. Tier three represents the database server and Tier n (the business logic tier) represents a dedicated Parallel Crystal Report Server for report generation.

For additional information please see our Parallel Crystal section.

Some of the many choices for a Web Application Servers include: