ABSTRACT
Time is an important parameter in a distributed system. Consistency maintenance among replicated data often relies on identifying which update is the most recent one. Real-time systems like air-traffic control must have accurate knowledge of time to provide useful service and avoid catastrophe. Important authentication services (like Kerberos) rely on synchronized clocks. Wireless sensor networks rely on accurately synchronized clocks to compute the trajectory of fast-moving objects. Before addressing the challenges related to time in distributed systems, let us briefly review the prevalent standards of physical time.
