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
for communication 2 arduino has succeeded. the child node successfully sends its sensor data to the master node.
but my obstacles.
how the master node reply to messages from the child node.
so the scenario I want, when the child node sends a message to the master node, the master node directly reply that the message has been received by the master node.
where the message is sent to the child node.
I am confused to rf24network how do one node can function to receive and send messages. in the example rf24network library there is only one-way communication where the transmitter sends the packet to the receiver.
can you help me with the problems I am facing so I can find a way out.
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