## 8.1 Preparing for Parallel Sysplex 

If your z15 is a member of a Parallel Sysplex or if you create a new Parallel Sysplex involving the IBM z15, time synchronization among CPCs is required. For time synchronization, you must use the Server Time Protocol feature (FC #1021). In addition to the time synchronization, the following tasks are required in preparation for Sysplex: 

1. Defining CF (coupling) links. 

2. Defining FICON CTC connections (optional). 

3. Defining the CF LPAR. 

4. Defining the CF LPAR image profile in HMC. 

5. Configuring STP. 

Defining CF (coupling) links is described in Chapter 9, “Defining Coup ling Facility links” on page 193. Defining the image profile is described in 5.4, “Creating an Image Profile on the 8561 Support Element” on page 102. 

## 8.2 Preparing for non-sysplex system time synchronization 

If your z15 is not part of a Parallel Sysplex but you want to synchronize the time among multiple CPCs, you need the STP function and STP-only (timing) links. These configuration steps are required: 

1. Defining STP-only (timing) links. 

2. Configuring STP. 

Defining STP-only (timing) links is described in 9.5, “Defining an STP timing-only link by using ICA SR” on page 207. 

## 8.3 Server Time Protocol overview 

This chapter describes how to set up STP on a z15 server. 

STP provides time synchronization among multiple CPCs in a Coordinated Timing Network (CTN). CTN is a collection of servers that are synchronized to a time value called Coordinated Server Time (CST). STP function (feature) is implemented in the Licensed Internal Code (LIC) as a chargeable feature. You must order STP enablement feature code #1021 to use STP. 

For more information about STP concepts and planning information, see the Server Time Protocol Planning Guide , SG24-7280. 

