Multitier architecture

Multitier architecture, also known as n-tier architecture, is a client-server architecture in which presentation, application processing, and data management functions are physically separated. The most common form of this architecture is the three-tier architecture, which divides the architecture into the presentation tier, the logic tier, and the data tier.

Overview

Multitier architecture aims to enhance scalability, performance, manageability, and the reuse of components. Each tier is responsible for a specific functionality. The Presentation tier is the topmost level of the application and is responsible for interacting with the user. The Logic tier (also known as the middle tier or application tier) contains the business logic and information processing of the application. The Data tier includes the data persistence mechanisms (database servers, file shares, etc.) and the data access layer that encapsulates the persistence mechanisms and exposes the data.

Advantages

• Scalability: The separation of concerns among the tiers allows for scaling up or down as needed independently in each tier.
• Flexibility: Changes or updates can be made to one tier without affecting the others.
• Maintainability: Issues can be isolated and addressed without impacting other tiers.
• Reusability: Components, such as business logic or data access layers, can be reused across different parts of the application or in different applications.

Disadvantages

• Complexity: The architecture can introduce complexity, making the system harder to understand and manage.
• Performance: The overhead of communication between tiers can impact performance, especially if not properly managed.
• Deployment: Deploying and managing applications across multiple tiers can be more challenging than in simpler architectures.

Types of Multitier Architectures

• Two-tier architecture: Divides the application into a client and a server. The client handles both presentation and application layers, while the server handles the data layer.
• Three-tier architecture: The most common form, separating the application into the presentation, application, and data tiers.
• N-tier architecture: An extension of the three-tier model that allows for additional layers, such as a separate business layer, service layer, or integration layer.

Examples

• Web Applications: Often use a three-tier architecture consisting of a web browser (presentation tier), web server (application logic tier), and database server (data tier).
• Enterprise Applications: May use an n-tier architecture to separate business logic, data access, and presentation layers from each other for better scalability and maintainability.

See Also

• Client-server model
• Software architecture
• Service-oriented architecture (SOA)
• Microservices