*** What is n-Tier Architecture?
N-Tier architecture refers to the architecture of an application that has at least 3 "logical" layers -- or parts -- that are separate. Each layer interacts with only the layer directly below, and has specific function that it is responsible for.
Why use n-Tier architecture? Because each layer can be located on physically different servers with only minor code changes, hence they scale out and handle more server load. Also, what each layer does internally is completely hidden to other layers and this makes it possible to change or update one layer without recompiling or modifying other layers.
This is a very powerful feature of n-Tier architecture, as additional features or change to a layer can be done without redeploying the whole application. For example, by separating data access code from the business logic code, when the database servers change you only needs to change the data access code. Because business logic code stays the same, the business logic code does not need to be modified or recompiled.
1. Presentation Layer
2. Business Tier
3. BLL and DAL
4. Data Tier
5. Logical Layers vs. Physical Layers (Distributed)
a logical layer means that layers are separate in terms of assembly or sets of classes,
Physical layer means that those assemblies or sets of classes are hosted on different servers with some additional code to handle the communication between the layers. E.g. remoting and web services.
N-Tier Architecture is nothing but splitting your solution into different project based on the business requirement.
- Reduce the business and the programming complexity.
- Easy to process
multi-tier architecture (often referred to as n-tier architecture) is a client-server architecture in which the presentation, the application processing, and the data management are logically separate processes. For example, an application that uses middleware to service data requests between a user and a database employs multi-tier architecture. The most widespread use of "multi-tier architecture" refers to three-tier architecture.