Kellosynkronointi

Kellosynkronointi, or clock synchronization, is the process of coordinating the time kept by multiple computer systems or devices so that their internal clocks remain consistent. Accurate timekeeping is essential for distributed computing, data consistency, logging, security protocols, and real‑time systems.

The concept dates back to the early days of mainframe computing, but widespread use began with the Network Time Protocol (NTP) in the late 1980s. NTP allows hosts to obtain time from more accurate sources such as atomic clocks or GPS receivers. Modern refinements include Precision Time Protocol (PTP) defined in IEEE 1588 for high‑precision applications in industrial automation and telecom, and the Simple Network Time Protocol (SNTP) for lightweight, less critical environments.

Clock synchronization typically operates in a hierarchical fashion. A root or primary time source—often a GPS‑disciplined oscillator—provides a reference that local servers adjust to. Clients then adjust their clocks based on jitter and offset measurements, using algorithms such as the Kalman filter in PTP or statistical filtering in NTP. The adjustment process must account for network latency and asymmetry to avoid drift.

Common use cases span financial transaction timestamping, coordinated sensor networks, and distributed databases that rely on consistent ordering of events. In cloud computing, synchronization services (e.g., Amazon Web Services Time Sync Service) help maintain coherence across microservices. Without reliable Kellosynkronointi, systems face data inconsistencies, security lapses, and degraded performance.