Difference between tier and layer?

Heloo guys,

I would like to know what is the difference between tier and layer. I have often heard from developers that we are using n tier architecture and there are many layers like (Business layer(BL),Data Access Layer(DAL) in an application.

Thanks,

Sumit

Logical layers are a way of organizing your code. Typical layers include Presentation(UI), Business(BL) and Data(DAL) – the same as the traditional 3-tier model. But when we’re talking about layers, we’re only talking about logical organization of code. In no way is it implied that these layers might run on different computers or in different processes on a single computer or even in a single process on a single computer. All we are doing is discussing a way of organizing a code into a set of layers defined by specific function.

Physical tiers however, are only about where the code runs. Specifically, tiers are places where layers are deployed and where layers run. In other words, tiers are the physical deployment of layers.

For example let's say you have application with separate UI and BL and DAL every thing running on a single sythts stem 3 layer and 1 Tier.

GUI in One System, BL is in diffrent systerm and  DAL is in diffrent sysetem then its a 3 tier Arch.

Every thing (GUI+BL+DAL ) are in a mainting in the same system then its called Single tier.

you distributed every thing in to diffrent system then that is N tier Arch.

Is there any one tier or two tier architecture?

SumitArora said:

I would like to know what is the difference between tier and layer.

Simply a “layer” is a logical representation ( eg. DAL, BAL and Presentation), whereas a “tier” is a physical representation (eg sharing layers from one physical project to another ~ it could be in same machine or other).

Check this article for more info: http://srinivasrb.wordpress.com/2009/06/02/layers-and-tiers/

mohit said:

Is there any one tier or two tier architecture?

Yes..

One tier is commonly called as Mainframe architecture wherein a piece of data are stored in a single machine.

Two tier is called as Client/Server architecture wherein an application is running in the client machine which interacts with the server.

Vinz said:

 

mohit said:

Is there any one tier or two tier architecture?

Yes..

One tier is commonly called as Mainframe architecture wherein a piece of data are stored in a single machine.

Two tier is called as Client/Server architecture wherein an application is running in the client machine which interacts with the server.

Hi vinz

Can you please explane me,what is mainframe architecture?and if systems are configured as peer to peer network than

the tier architecture can't be deployed?

ajit said:

Can you please explane me,what is mainframe architecture?

Single tier (mainframe arch) consists of a MainFrame host connected directly to a terminal. This means that users could access this centralized computer only by means of terminals.

ajit said:

and if systems are configured as peer to peer network than

the tier architecture can't be deployed?

No, Actually I'm refering to multi tiers...