Hi Sreenath,
NTP and PTP have some similarities. NTP is the most common protocol to sync clocks on your network, that’s what you will mostly see on networks nowadays. We use it to sync the clock on network devices but also computers/servers etc. NTP uses software timestamping and supports millisecond synchronization.
PTP is similar to NTP but uses hardware timestamping and offers nanosecond or picosecond-level synchronization.
For 99% of the devices, NTP is good enough but if you have devices where millisecond-level synchronization is not good enough, PTP is another option (I have never seen it on a network btw).
Synce is something different. You can read an explanation here:
It’s used for frequency synchronization on certain networks.
Rene