Do P2MP networks use acknowledgement (ACK) messages?


I’m back again because the datasheet is lacking in detail about specific actions of various transmission interactions.
I’m developing products which use XBee 3 DigiMesh 2.4 and the XBee SX SMT modules. The SX module will be used in a P2MP network.

I will have an indirect message coordinator and multiple indirect poller end devices which are in asynchronous sleep and in API mode. These end devices send a digital input sample to the coordinator immediately after waking, that’s their ONLY job; then they go back to sleep. This is, of course, is a P2MP network (TO = 0x40). In this scheme, when the end device(s) automatically send their digital input sample API frame after waking from sleep, do they wait for an acknowledgement from the coordinator before sleeping again provided the wake time is long enough?


Yes, all of the Digi XBee products use an ACK system when configured in a point to point network.

Thanks for the answer. So what is the detailed operations if an acknowledgement is not received? The indirect poller will retry for the number of times given in RR, correct? If it reaches the limit given in RR, will it go back to sleep at my set interval, wake up again, transmit the number given in RR, go back to sleep, and repeat this cycle indefinitely, or is there a total amount of retries that are possible even between sleep cycles?

The module will attempt to transmit the packet 1+RR times. Once this value has been done, it will discard the packet if it the ACK had not been received and move on to the next packet. If there is no more packets and sleep mode is enabled, it will cycle to sleep. Then the process occurs all over again on the next wake cycle when a New packet is sent into the UART.