title: Layers in 4 Tier Architecture in ASP.Net
body: <p>As per <a href="http://www.dotnetfunda.com/articles/article18.aspx" rel="nofollow">this</a> article in 4 tier architecture, Business object is also consider as layer.</p>
  
  <p>In this application we will have following 4-Tiers (As given on blog)
  1. Business Object [BO] 
  2. Business Access Layer [BAL] 
  3. Data Access Layer [DAL] 
  4. UI (4-Tier) folder [UI] </p>
  
  <p>I want to clear, In Software architecture, Do we consider Business Object as a separate layer ?</p>
  
  <p>My second question is </p>
  
  <p>If we have two tier architecture it means we can have two physical servers, One server can have only DB (Database Server) and other server will consist Presentation (UI), Business Logic, Data Access Layer and Business Object. Is it correct ?</p>
  
  <p>and</p>
  
  <p>In three tier we can deploy UI layer on one server (T1) ,  Business Logic, Data Access Layer, Business Object on an other server (T2) and Database separate  server (T3). In this case we have to create service (.Net service or WCF or remoting) to expose object for UI layer.</p>
  
  <p>I am not sure about 4 tier architecture. As per  <a href="http://www.dotnetfunda.com/articles/article18.aspx" rel="nofollow">[this]</a> article it describe 4 layers includes business object (BO). I am not sure whether we consider BO as layer or not ?</p>
  
  <p>Looking for kind help as i found. </p>