Robin2:
Your writing is very hard to understand because you have a whole lot of thoughts jumbled together. And some of the seem incomplete. See how much easier it is to make sense of it when I break up your Reply #2 into paragraphs
I think when you read it the way I have presented it you will see that some parts are hard to understand.I am not familiar with the network library - I have never needed to use it. However I am 99% certain that every message that is transmitted is automatically acknowledged without you needing to do anything.
You have not replied to my second question in Reply #1 "Do you really need to use the network feature? Please describe the project you want implement - there may be an easier way."
...R
my project. I want to send the temperature sensor data and humidity of the room to the master node -> master node receive and store sensor data. then the master node sends a command to the slave node to turn on the light -> slave node receives commands from the master node and turns on the light.