LoRaWAN defines three classes of communication. In summary, class A transmits the data then listen on RX1 and RX2, class B periodically listen on RX2 on defined time slots, Class C always listen to RX2 unless it transmits. Moreover, Class C listen on RX2 after transmitting directly for a short period than open RX1 to listen. I know that upload is the most used and download rarely used unless there is acknowledgement for a message or updating parameters to reconfigure the device, etc. My question is why Class B and C devices usually listen on RX2 and class A not listen unless it transmits? For example, why class A does not listen to RX2 before transmitting? Latency of one second will not be a problem. In this case class A mechanism will be as follow: A data ready to send --> listen on RX2 --> transmit --> listen on RX1 --> listen on RX2. While the current mechanism of class A is: transmit --> listen on RX1 --> listen on RX2.