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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

Answers

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.

     

    HTH,

    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:

     

    Presentation

    UI

    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.

     

    HTH,

    Suprotim Agarwal

    Wednesday, June 25, 2008 2:33 AM