title: When do we have web server and an application server as two separate physical tiers?
body: <p>Typically when an application is deployed on a server farm, it has a central database, one or more application servers and one or more web servers.</p>
  
  <p>Since all the services in the application tier are going to be accessed via the web server, why not deploy the web server on the same physical tier as that of the application server?</p>
  
  <p>The specific query is - what are the reasons of deploying the web server as a separate tier?</p>
  
  <p>On a broader perspective, what are the general considerations while deciding on the deployment scenario? </p>