Cristian’s Algorithm
https://en.wikipedia.org/wiki/Cristian%27s_algorithm
Berkeley Algorithm
https://en.wikipedia.org/wiki/Berkeley_algorithm
Network Time Protocol (NTP)
Simple Network Time Protocol (SNTP)
https://en.wikipedia.org/wiki/Network_Time_Protocol
Precision Time Protocol (PTP)
https://en.wikipedia.org/wiki/Precision_Time_Protocol