As I refer from UG103.2: Zigbee Fundamentals, 4.2.1 Description of Relevant Neighbor Table Fields:
The age field measures the amount of time since the last neighbor exchange message was received. A new entry starts at age 0. The age is incremented every EM_NEIGHBOR_AGING_PERIOD, currently 16 seconds. Receiving a neighbor exchange packet resets the age to EM_MIN_NEIGHBOR_AGE, as long as the age is already at least EM_MIN_NEIGHBOR_AGE (currently defined to be 3). This makes it possible to recognize nodes that have been recently added to the table and avoid evicting them, which reduces thrashing in a dense network. If the age is greater than EM_STALE_NEIGHBOR (currently 6), the entry is considered stale and the outgoing cost is reset to 0.
I see EM_MIN_NEIGHBOR_AGE value equal 3 and EM_STALE_NEIGHBOR value equal 6. I want to ask where these macro is defined in EmberZnet 22.214.171.124 source code? Can I modify value of these macro?
That's something defined in the stack, normally user don't need to modify them.