What is Server Time Protocol (STP)?

Server Time Protocol is a server-wide facility that is implemented in the Licensed Internal Code (LIC) and presents a single view of time to Processor Resource/Systems Manager™ (PR/SM™).

Key benefits

  • Eliminate the infrastructure requirements of Sysplex Timers (space, power, etc) and fiber optics
  • Save on maintenance costs
  • Support a multisite timing network of up to 100km (62 miles), allowing a sysplex to scale with distance
  • Dedicated links are no longer required to transport timing information

How it works

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

Learn more

STP requirements

STP is available starting with the z890/z990 family of servers, and is supported by z/OSe V1.7, and z/OS V1.7 and above.

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