title: what is the difference between tier and layer in c#
body: <p>I have difficulty in understanding difference between tier and layer in c#. In my project my team leader asked me do it in n-tier architecture I did sample form and showed to him and he said that's 3-layer architecture. What is the difference between layer and tier i am still confused.
  I took two classes one for business logic, one for data acccess</p>
  
  <pre><code>class bll
  {
     //code for business logic
  }
  
  class dll
  {
     //code for connection string
  }
  </code></pre>
  
  <p>one more .cs</p>