Distributed N-Tier client/server architecture allows for segments of an application to be broken up and distributed across multiple locations on a network.  Listed below are standard tiers in a Distributed N-Tier System.

End-User Client Tier

The End-User Client is responsible for sending and receiving requests from web servers and other applications servers and translating the responses so that the End-User can interpret the data effectively.

The primary roles for this tier are to communicate with servers and translate server responses back to the end-user to interpret.

Business-Specific Functions

• Validate Data
• Display Data
• Send Data to Webserver

Web Server Tier

The Web server tier processes new requests for information coming in from the HTTP and HTTPS ports. This primarily handles the generation of user interfaces and calls the application server when needed to access Data and business logic when needed.

Business-specific functions

• Send Data to application server
• Format Data for Display
• Validate Data

Application Server Tier

The application server stores and executes predefined business logic that is applied to various pieces of data as the business determines. The processed data is then returned back to the Webserver. Additionally, this server directly calls the database to obtain and store any data used by the system

Business-Specific Functions

• Validate Data
• Process Data
• Send Data to Database Server

Database Server Tier

The Database Server is responsible for storing and returning all data need by the calling applications.

The primary role for this this server is storage. Data is stored as needed and can be recalled at any point later in time.

Business-Specific Functions

• Insert Data
• Delete Data
• Return Data to Application Server