Hallo seniors and anyone help me please,
If I have several devices (example 100 devices) trying to use ABP method.
- How often and how long does the activation take for each device, because it will takes time and consider about the efficiency and security part.
- Is physical access to device necessary (e.g press button)?
- Do all devices consider the security part use the same key?
- When does ABP needs to be re-initialized?
Thank you very much 
brocaar
2
Have you read the LoRaWAN specification on ABP? That might be a good start to understand how ABP works and what limitations there are 
https://lora-alliance.org/lorawan-for-developers
acourt
3
As @brocaar has mentioned, this is a clear instance of you needing to RTFM.
However, I just want to point out that the answers to your questions are highly dependent on the device you are deploying.