't send an ACK for a message, CCS will just resend it.
</p>
<p>CCS also sends an ACK or NACK for each server-to-device message. If you do not receive either, it means that the TCP connection was closed in the middle of the operation and your server needs to resend the messages.
</p>

<h3 id="msg_examples">Message Examples</h3>

<p>Here is an XMPP stanza containing the JSON message from a 3rd-party server to CCS:

</p>
<pre>&lt;message id=&quot;&quot;&gt;
  &lt;gcm xmlns=&quot;google:mobile:data&quot;&gt;
  