What is 3-tier Architecture

    Application architecture's : Every application contains 3 different parts in it like:

1. UI Part
2. Logic Part ( BL + DL)
3. Data Source Part

 3-tier or N-tier  Architecture  :  

          In this model all the 3 parts will sit on 3 different machines to execute, on the client machine what we have is only light weight client (UI) which will connect with the logic part residing on server machine that will in turn  connect with the DB server. Maintenance of the software becomes easier in this model when there were more number of client accessing the application.