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Multi-tier Architecture See also

High-level Analysis of the Architecture

1.1 Basic Three-Tier Architecture

Three-Tier Architecture has three layers User Interface layer, business logic layer and the persistence layer.

The three-tier software architecture emerged in the 1990s to overcome the limitations of the two-tier architecture the third tier (middle tier server) is between the user interface (client) and the data management (server) components. This middle tier provides process management where business logic and rules are executed and can accommodate hundreds of users (as compared to only 100 users with the two tier architecture) by providing functions such as queuing, application execution, and database staging. The three tier architecture is used when an effective distributed client/server design is needed that provides (when compared to the two tier) increased performance, flexibility, maintainability, reusability, and scalability, while hiding the complexity of distributed processing from the user.

1.1.1 3-Tier Architecture

The 3-tier architecture overcomes the weaknesses of the 2-tier and client/server architectures. It contains a client workstation, a component server, and a database server. The user interface is on the client side while business logic and data management are in dedicated tiers. Business logic resides on one machine where it can be easily managed. Successful implementation of a 3-tier architecture requires considerable applied experience.

n-Tier Architecture

The n-tier architecture is the same as the 3-tier architecture, but it has multiple (n) component and data management servers. It can distribute components across multiple servers and can access data in multiple databases. However, it requires careful planning of component interfaces to enable re-use and sharing.

1.1.2
Tier-to-Tier Communication