The GCM Cloud Connection Server (CCS) allows third party servers to communicate with Android devices by  establishing a persistent TCP connection with Google servers using the XMPP protocol. This communication is asynchronous and bidirectional.</p>
<p>You can continue to use the HTTP request mechanism to send messages to GCM servers, side-by-side with CCS which uses XMPP. Some of the benefits of CCS include:</p>
<ul>
  <li>The asynchronous nature of XMPP allows you to send more messages with fewer resources