title: GCM Application server inside web service
body: <p>I created an Android application that allows a user to send a Message to other users. In order to achive this, I used <code>GCM</code>. So, a user can send a message using a web service (developed using <code>Web API</code> framework), that save the message on the remote database (SQL Server) and contacts the GCM Server for delivering to the recipient the GCM message. </p>
  
  <p>It can happen that the message to GCM is not received, for example because the GCM server is temorary unavailable. So Google suggests to try the resend using an exponential backoff. And this is a problem for my architecture, since I call GCM from inside another WS (the one I created, that is used from a user for sending message to other user). If I try to use exponensial back-off my outer WS should be active, since the GCM return a valid response.</p>
  
  <p>So, seems that calling GCM web service from inside another web service is not a good thing. Is this right? Can you give me any suggestion? What is the most common architecture of IM application that uses GCM ?</p>