Interview Question Series - Tier vs Layer

• Layer is a logical separation, how to organize the code. E.g.: presentation (view), controller, models, repository, data access, and Tier is a physical separation, where the code / process runs. E.g.: client, application server, database server;
• Layers mainly help in architecture principal of Maintainability, to deploy separate code at separate server, in Tier helps in performance where we can improve app performance if we have more then 1 server, like app server and DB Server.
• Layers are like, presentation layer (or UI), business logic layer and Database Layer, and Tire is like 2 tire , with app server and DB server.