By default PTP targets select they grandmaster using the best clock algorithm (BMCA). Normally, you let this algorithm to select the best device as the master automatically. However, if you would like to manually select the grandmaster device you can follow two different approaches :
- If you want to specify a particular target as the grandmaster, you can set the Priority1 value to be the lowest on the network. The lowest the value the higher priority it has.
- You can also set the target all the targets to work on Slave Only mode and have only one device to work as master.
In order to implement this configurations you can check on the following document: Using NI-TimeSync to Configure IEEE 1588 and 802.1AS Time References