Recently we did a test with the Actility Network server and found 1 minor discrepancy between Actility and Chirpstack.
We noticed that for a confirmed uplink, Actility sends ACK on the same port as the application uplink while Chirpstack uses
null. This is just ACK without any additional MAC payload.
I checked the specification document of LoRaWAN v1.0.2 however, it does not specify which port to be used for ACK of confirmed uplink.
Is there a reason why Chirpstack uses fport
null for ACK of a confirmed uplink? or it is something that is free to interpret?
Note, we are using LoRaWAN v1.0.2, region EU868, class A in both situations.