2. The PTS SE recognizes the checkstop pending condition, and calls the PTS SE STP  code. 3. The PTS SE sends an ECAR request thorough HMC to the Backup Time Server (BTS)  SE. 4. The BTS SE communicates with the BTS to start the takeover. 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 ECAR support is faster than the original CAR support because the console path changes  from a 2-way path to a 1-way path. Also, almost no lag time is incurred between the system  checkstop and the start of CAR processing. Because the request is generated from the PTS  before system logging, it avoids the potential of recovery being held up. ECAR is available on z14 M0x, z14 ZR1, and z13/z13s systems on Driver 27 and later only. In  a mixed environment with previous generation machines, you should define a z14 M0x, z13,  or z13s system as the PTS and CTS.  Attention: z14 ZR1 does not support InfiniBand connectivity; therefore, it cannot be  connected by using coupling/timing links to a zEC12 or zBC12 CPC. As such, in a CTN  with zEC12 or zBC12, the z14 ZR1 cannot be assigned a role (PTS, CTS or Arbiter; its  failure affects the time synchronization functionality of other servers in the CTN).  For more information about planning and setup, see the following publications: With HMC 2.14.1, STP management was enhanced with two new actions: CTN split and CTN  merge. The HMC menus for Server Time Protocol (STP) were enhanced to provide support when  one or more systems must be split in to a separate CTN without interruption in the clock  source.  Requirements 11.5.8 CTN Split and Merge CTN Split Merging two CTNs The task is available under the Advanced Actions menu in the Manage System Time task.  Several checks are performed to avoid potential disruptive actions. If targeted CTN only has  members with the roles, task launch fails with error message. If targeted CTN has at least one  system without any roles, task launches. An informational warning is presented to the user to  acknowledge that sysplex workloads are divided appropriately. When two separate CTNs must be merged in to the single CTN without interruption in the  clock source, the system administrator must perform the Join existing CTN action, which is  available in the Advanced Actions menu. Note:  After joining the selected CTN, all systems within the current CTN are synchronized  with the Current Time Server of the selected CTN. A coupling link must be in place that  connects the CTS of the selected CTN and the CTS of the current CTN. 388  IBM 14 Model ZR1 Technical Guide