Lines Matching full:ack
66 <li>CCS: 3rd-party servers connect to Google infrastructure using a persistent XMPP connection and send/receive messages to/from all their devices at full line speed. CCS sends acknowledgements or failure notifications (in the form of special ACK and NACK JSON-encoded XMPP messages) asynchronously.</li>
130 <li>CCS adds the field {@code message_id}, which is required. This ID uniquely identifies the message in an XMPP connection. The ACK or NACK from CCS uses the {@code message_id} to identify a message sent from 3rd-party servers to CCS. Therefore, it's important that this {@code message_id} not only be unique, but always present.</li>
132 <li>For ACK/NACK messages that are special control messages, you also need to include a {@code message_type} field in the JSON message. For example:
134 <pre>message_type = ('ack' OR 'nack');</pre>
137 <p>For each message a device sends to the server, you need to send an ACK message. You never need to send a NACK message. If you don't send an ACK for a message, CCS will just resend it.
139 <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.
163 <p>Here is an XMPP stanza containing the ACK/NACK message from CCS to 3rd-party server:
170 "message_type":"ack"
222 <p>Here is the format of the ACK expected by CCS from 3rd-party servers in response to the above message:</p>
229 "message_type":"ack"
237 <p>Every message sent to CCS receives either an ACK or a NACK response. Messages that haven't received one of these responses are considered pending. If the pending message count reaches 1000, the 3rd-party server should stop sending new messages and wait for CCS to acknowledge some of the existing pending messages.</p>
239 <p>Conversely, to avoid overloading the 3rd-party server, CCS will stop sending if there are too many unacknowledged messages. Therefore, the 3rd-party server should "ACK" received messages as soon as possible to maintain a constant flow of incoming messages. The aforementioned pending message limit doesn't apply to these ACKs. Even if the pending message count reaches 1000, the 3rd-party server should continue sending ACKs to avoid blocking delivery of new messages.</p>
