.</li>
  <li>Communication is bidirectional&mdash;not only can the server send messages to the device, but the device can send messages back to the server.</li>
<li>You can send messages back using the same connection used for receiving, thereby improving battery life.</li>
</ul>

<p>The upstream messaging (device-to-cloud) feature of CCS is part of the Google Play services platform. Upstream messaging is available through the <a href="../../reference/com/google/android/gms/gcm/GoogleCloudMessaging.html"><c