Clock Synchronization
Synchronizing digital clocks across a distributed system
brings a number of potential benefits, including:
- early detection of remote failures;
- orchestrated use of shared resources such as network bandwidth;
- time-stamping of sensor data with globally meaningful time stamps; and
- coordinated sleep mode in communicating wireless devices for conservation of battery power.
Clock synchronization technologies include:
- IEEE 1588 Precision-Time Protocol (PTP) for IP on ethernet;
- time-triggered buses (TTA, ARINC, FlexRay, time-triggered ethernet); and
- wireless time synchronization protocols.
Clock synchronization is distinguished from frequency locking.
The former bounds the difference between clock values, whereas the latter
bounds the difference between clock rates. An example of a technology
that provides frequency locking but not time synchronization is synchronous
ethernet.