Why 3 Tier Architecture


The concept of three-tier architecture is one of the most popular frameworks in software engineering, used to create and deploy applications. This type of architecture separates the application into three distinct tiers, providing a structure that facilitates the deployment and management of the application. Each tier serves a specific purpose. The first tier normally consists of a web server, the second tier consists of the application server, and the last tier is the database server. All these components interact with each other to create and serve the application’s client.


The main benefit of three-tier architecture is that it allows for better scalability. By separating the application into distinct tiers, the components can be scaled independently of each other, allowing for a more efficient use of resources and improved performance. In addition, three-tier architecture facilitates the sharing of data between components and simplifies application development since each component can be tailored to specific tasks. Three-tier architecture is also advantageous because it provides an isolated environment that can protect the application from malicious activities and other kinds of online attacks.

Web Server Tier

The main purpose of the web server tier is to provide a user interface. This tier is responsible for receiving requests from the user, passing the data between the other tiers, and generating a web page to the client. In order to serve this purpose, web servers use dynamic scripting languages such as PHP, ASP.NET, and Java Server Pages. Additionally, web servers provide additional features such as caching, session control, and authentication.

Application Server Tier

The application server tier is responsible for processing requests from the web server tier. In this tier, business logic and application logic is processed, meaning that it contains the actual functionality of the application that is being built. Programmers can take advantage of this tier to customize their applications with custom algorithms, database access, and other complex processes.

Database Server Tier

The database server tier is responsible for the management and storage of data. This includes the creation of tables and the insertion and retrieval of data. Databases are key for applications, as they allow for the storage of large amounts of structured data which can be used to power an application. Database servers usually utilize open source software such as MySQL or PostgreSQL, or they may use commercial software such as Oracle and Microsoft SQL Server.


To implement three-tier architecture, a web server and database must first be setup. Once these components are in place, application logic can be added to the application server tier. The application must then be tested for functionality and performance before being deployed to production.


Despite its benefits, three-tier architecture also has some drawbacks. The most significant of these is the cost. The overhead of deploying and managing the three tiers may be too high depending on the size and complexity of the application. Additionally, the performance of the application may suffer if the three tiers are not perfectly distributed.


When implementing three-tier architecture, it is important to consider performance. To ensure that the application is responding quickly, it is necessary to optimize each component. A web server must be properly configured to cache contents, utilize connection pooling and use session control. Application servers must be optimized for cache utilization, the database should be regularly maintained, and databases must be properly indexed for improved queries.

In Summary

Three-tier architecture has become the standard in software engineering due to its scalability, modularity, and ease of maintenance. It can be costly and challenging to deploy, however, so it must be carefully implemented and optimized for maximum performance. With the right implementation, three-tier architecture can provide a powerful solution for creating and deploying applications.

Anita Johnson is an award-winning author and editor with over 15 years of experience in the fields of architecture, design, and urbanism. She has contributed articles and reviews to a variety of print and online publications on topics related to culture, art, architecture, and design from the late 19th century to the present day. Johnson's deep interest in these topics has informed both her writing and curatorial practice as she seeks to connect readers to the built environment around them.

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