5 tier design RRS feed

  • Question

  • I know nothing about n-tier design, but wish to learn.  I have a simple question.  What are the 5 tiers of a 5 tier architecture and what is the purpose of each tier?

    Tuesday, June 24, 2008 5:35 AM


All replies

  • Hi,


    Just to add to it, as a thumbrule, whenever I design applications, I concentrate on the layers(logical seperation) more than the tiers(physical). Once the layers are ready, it is based on the requirements (some non-functional) that a decision is taken of choosing where to place each layer into a tier and a trade-off is done between performance, scalability and security.


    Remember that the more the tiers, the more are the network hops, increased cost and maintainability.



    Suprotim Agarwal


    Tuesday, June 24, 2008 5:53 AM
  • Basically I have an application that is essentially a 2 tier design.  Functionally its fine, but its organization is a complete mess, and I would like to clean it up so that it can be presented to my company that likes to use a n-tier (in this case 5-tier) design architecture.


    If I understand things right, anything larger than a 2 tier design, is called n-tier. 


    The 3 basic tiers are as follows:


    1)  Presentation Tier

    2)  Business Tier

    3)  Data Tier


    Breaking down the 3 basic tiers, they can be further defined as follows:


    1)  Presentation Tier

         A)  GUI

    2)  Business Tier

         A)  Business Logic Layer (BLL)

         B)  Data Access Logic (DAL)

    3)  Data Tier

         A)  Database File(s)


    Looking at the breakdown of the 3 basic "tiers" I can only count 4 layers, what is the 5th layer?

    Tuesday, June 24, 2008 6:17 AM
  • Hi,


    The 5 logical layers could be:




    Business Logic

    Data Access

    Data and Storage Management


    Let me suggest you a link where you can understand this better. The link is from an amazing book 'Expert C# Business Objects' from Lhotka and is used by many architects througout. It's a must have in your collection.



    Suprotim Agarwal

    Wednesday, June 25, 2008 2:33 AM