This is a common misconception - that STP is somehow dependent on the NTP server(s) used to synchronize to an ETS for STP availability. If an NTP server is configured on the PTS or BTS server then STP will synchronise time to the ETS. However, there is no impact to the STP CTN if there is an NTP failure. It just means that STP is longer synchronising to the ETS and so STP time will gradually lose accuracy as the TOD on the current time server (CTS - stratum 1) CPC drifts. However, if the NTP server was a stratum 1, STP will "calibrate" to the NTP server and use fine/base steering to remain accurate. Regardless of the stratum level of the NTP server, the STP CTS (either the PTS or BTS) is stratum 1.
Regards, George Kozakos IBM Mainframe Discussion List <[email protected]> wrote on 17/10/2014 10:03:14 AM: > From: Scott Chapman <[email protected]> > To: [email protected] > Date: 17/10/2014 10:03 AM > Subject: Re: STP > Sent by: IBM Mainframe Discussion List <[email protected]> > > FWIW: we use STP, and use a couple of HMCs as the NTP source for > STP, with the HMC servers themselves getting time from our stratum 1 > NTP servers which use a GPS receiver for the time. That makes the > HMC stratum 2. And if z/OS was then serving the time via NTP, I > believe z/OS would be considered stratum 3. But I see little point > in that: there's more stratum 2 servers distributed around our network. > > Of course one may reasonably argue that STP could/should point > directly to the stratum 1 NTP server. Which is probably a fair > point. But I tend to be biased against making my mainframe > configuration directly dependent on something I don't have direct > control over. That's just one of my little quirks... > > Scott ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
