STP uses a message-based protocol in which timekeeping information is passed over externally defined Coupling Links. These can be the same links that already are being used in a Parallel Sysplex for Coupling Facility (CF) message communication. The STP design has introduced a Coordinated Timing Network (CTN), a collection of servers and coupling facilities that are time synchronized to a time value called Coordinated Server Time.
Key functions include the ability to:
- Set the Coordinated Server Time within 100 milliseconds of an international time standard either manually or by dialing out to a time service
- Schedule periodic dial-outs to a time service so that Coordinated Server Time may be gradually steered to an international time standard
- Initialize Time Zone offset, Daylight Saving Time (DST) offset, and Leap seconds offset
- Automatically schedule Daylight Saving Time, based on the selected Time Zone
- Adjust Coordinated Server Time by up to +/- 60 seconds