Acknowledged data transmission to sleeping end device

When data is sent and an acknowledgment is required from the receiver, a timeout of approximately 1600 ms is applied to the acknowledgment. If no acknowledgment is received by the sender within this timeout period, the data is automatically re-sent. Up to 3 more re-tries can subsequently be performed, totalling just over 3 seconds before the data transfer is finally abandoned.

In the case of data sent to a sleeping End Device, the acknowledgment is generated by the End Device after collecting the data from its parent. Thus, if the data is not collected within the acknowledgment timeout period, the data is re-sent to the End Device (via its parent).

Note: There can be a case when the buffered data is collected by the End Device after the final re-try by the sender but before the data is discarded by the parent (between approximately 3 and 7 seconds after the initial transmission). In such cases, the acknowledgment that is eventually generated by the End Device is ignored by the sender, since the transaction has already timed out and terminated.

Parent topic:Sending data to sleeping end devices