What is the difference between internal clock synchronization and external clock synchronization in distributed systems?
Clock Synchronization in Distributed System.
What is the difference between internal synchronization and external synchronization in distributed systems?
Answer
Clock synchronisation in distributed usually follows one or both of the following goals: (1) making sure that all nodes that are part of the distributed system have the same internal clock, and (2) making sure that the distributed system is in sync with another external clock.
Internal synchronisation is usually done through sync protocols which allow a compute cluster to sync up their local clocks. The machines agree on using a common time. However, the time they agree on does not necessarily need to be in sync with an external clock i.e. with the time in a certain timezone.
External synchronisation makes sure that computing systems sync their clock with an external time source such as a server providing time using the NTP protocol. The goal is to have the computing system to sync up with the time in a certain time-zone. If very exact time is required usually NTP systems that generate time from an atomic clock are used.
In both cases internal and external synchronisation the protocol NTP can be and is widely used.