20 May

N-Tier architecture is a client–server architecture in which presentation, application processing and data management functions are physically separated.  

The most widespread use of multitier architecture is the three-tier architecture. The model is based on segregating an application into tiers, developers acquire the option of modifying or adding a specific tier, instead of reworking the entire application. 

Note: layers and tiers are often used interchangeably, however there is a difference. A layer is a logical structuring mechanism for the elements that make up the software solution, while a tier is a physical structuring mechanism for the system infrastructure.