content_image/984194.jpg
The z14 ZR1 server cannot participate in a mixed CTN; it can participate in an STP-only CTN only. 

## STP with PPS timing signal accuracy 

STP tracks the highly stable and accurate PPS signal from the NTP server and maintains an accuracy of 10 µs  to the ETS, as measured at the PPS input of the z14 ZR1 server. 

## STP without PPS timing signal accuracy 

If STP uses an NTP server without  PPS, a time accuracy of 100 ms to the ETS is maintained. 

The OSCs cards are plugged into the rear of the CPC drawer in slots LG11 and LG12. 

Tip:  STP is available as FC 1021. It is implemented in the Licensed Internal Code (LIC), and allows multiple servers to maintain time synchronization with each other and synchronization to an ETS. For more information, see the following publications: 

## 2.3.2 System control 

GLYPH<SM590000> Server Time Protocol Planning Guide , SG24-7280 

GLYPH<SM590000> Server Time Protocol Implementation Guide , SG24-7281 

GLYPH<SM590000> Server Time Protocol Recovery Guide,  SG24-7380 

The various system elements are managed through the Flexible Server Processors (FSPs). An FSP is based on the IBM PowerPCfi microprocessor technology. Each FSP card has two ports to connect to two internal Ethernet LANs through the internal network switches (SW1 and SW2). The FSPs communicate with the SEs and provide a subsystem interface (SSI) for controlling components. 

An overview of the system control design is shown in Figure 2-11. 

<img src='content_image/984194.jpg'>

Note:  The maximum z14 ZR1 configuration has one CPC drawer and four PCIe+ I/O drawers. The various supported FSP connections are referenced in Figure 2-11. 

