2-Tier Client-Server Architecture.

Generally any business application requiring data consist of four major pillars viz. the actual database, the transaction logic, the application logic and user interface. To support ever increasing customer need, decentralization of above tasks is proposed. This decentralization leads to division of work amongst different nodes (a.k.a tiers). The client (tied) is dedicated for presentation of data to the user in most flexible and suitable format. These services handle user interface actions and main business application logic. The server (tier 2) is meant for providing data services to the client. It involves providing access to requested independent of its location along with data validation.Fig.9.5 gives a general schematic of this type of architecture.

 

However, such systems suffer from following cons:

1. Client reuires more resources (processor memory, disk requirements are high) as it is running user interface as well as business application logic. In today's generation there lies a need to have light weight clients performing only interaction with servers.
2. It causes a significant overhead on client side administration and maintenance.

To deal with such major drawbacks there lies a need of separation between client end and business logic processing. This separation is achieved in 3-tier architecture.