2.2.2 Oscillator 4 Manage System Time With z15 Model T01, the oscillator card design and signal distribution scheme is new;  however, the RAS strategy for redundant clock signal and dynamic switchover is unchanged.  One primary OSC card and one backup are used. If the primary OSC card fails, the  secondary detects the failure, takes over transparently, and continues to provide the clock  signal to the CPC. On z14, HMC 2.14.1 provided a significant user experience enhancement for timing controls  with the new Manage System Time task.  For simplification, the z15 (2.15.0) removes the Support Element “Sysplex/System Timer”  task panels. HMC level 2.15.0 (Driver 41) is required to manage system time for z15. IEEE 1588 Precision Time Protocol (PTP) $^{a}$: In the future, IBM plans to introduce PTP as  an external time source for IBM Z Server Time Protocol (STP) for an IBM Z Coordinated  Timing Network (CTN). The initial implementation is for PTP connectivity by using the IBM  Z HMC/Support Element (SE). At that time, the use of STP CTNs for time coordination will not be changed, other than the  potential to use a PTP-based external time source. Future implementation is planned to  include full connectivity of an external PTP time source directly to the IBM Z CPC, and the  reintroduction of the concept of a mixed CTN, with support for traditional STP and native  PTP implementations. Beyond that, the goal is to enhance the role of IBM Z machines in a  PTP environment that addresses the many governmental regulations and security  concerns that our clients are facing. a. Statements by IBM regarding its plans, directions, and intent are subject to change or  withdrawal without notice at the sole discretion of IBM. The development, release, and timing  of any future features or functionality described for IBM products remain at the sole discretion  of IBM. The SEs provide the Simple Network Time Protocol (SNTP) client function. When Server  Time Protocol (STP) is used, the time of an STP-only Coordinated Timing Network (CTN) can  be synchronized to the time that is provided by a Network Time Protocol (NTP) server. This  configuration allows time-of-day (TOD) synchronization in a heterogeneous platform  environment and throughout the LPARs running on the CPC. The accuracy of an STP-only CTN is improved by using an NTP server with the PPS output  signal as the External Time Source (ETS). NTP server devices with PPS output are available  from several vendors that offer network timing solutions. Consider the following points: GLYPH<SM590000> A new card combines the FSP and OSC was implemented with z15. The internal physical  cards (FSP and OSC) are separate, but combined as a single FRU because of a  packaging design. GLYPH<SM590000> Two local redundant oscillator cards are available per CPC drawer each with one PPS  port. GLYPH<SM590000> An enhanced precision oscillator (20 PPM$^{5}$ versus 50 PPM on previous systems) is used. 4 Oscillator card (OSC) is combined (single FRU P/N) with the Flexible Support Processor (FSP); installed in pairs for each CPC Drawer 5 PPM - Parts Per Million 46  IBM z15 (8561) Technical Guide