3tier architecture and Multitier architecture

multi-tier architecture (often referred to as n-tier architecture) is a

client–server architecture in which

the presentation,
the application processing, and
the data management

are logically separate processes

The most widespread use of multi-tier architecture is the three-tier architecture.

There should be

a presentation tier,
a business or data access tier, and
a data tier.

Three-tier architecture

It was developed by John J. Donovan

The three-tier model is a software architecture and a software design pattern.

a change of operating system in the presentation tier would only affect the user interface code.

Presentation tier

-This is the topmost level of the application.

-The presentation tier displays information related to such services as browsing merchandise, purchasing, and shopping cart contents.

-It communicates with other tiers by outputting results to the browser/client tier and all other tiers in the network.

Application tier (business logic, logic tier, data access tier, or middle tier)

-The logic tier is pulled out from the presentation tier and, as its own layer, it controls an application’s functionality by performing detailed processing.

Data tier

-This tier consists of database servers.

-Here information is stored and retrieved.

-This tier keeps data neutral and independent from application servers or business logic. Giving data on its own tier also improves scalability and performance.


Data transfer between tiers is part of the architecture.

Protocols involved may include one or more of SNMP, CORBA, Java RMI, .NET Remoting, Windows Communication Foundation, sockets, UDP, web services or other standard or proprietary protocols.

Often middleware is used to connect the separate tiers.