- Presentation, processing, Data storage / retrieval are split into separate tiers
- Presentation tier: How the data is presented to the user
- Application tier: The application logic / functions of the application
- Data Storage / Retrieval tier: How the data is structured, stored, retrieved and updated
- The Client (eg. Browser, stand alone client) is sometimes considered a fourth tier
- One tier can to be updated without impacting other tiers
- Division of labour
This is a typical three – tier architecture. These tiers can be further sub-divided into more tiers, hence the name “n-tier”.