ISTR that all time references in a SYSPLEX must be within a certain tolerance 
(I have no recollection of the actual value). 
If the local time source exceeded this tolerance, the ETR (STP/9037) would 
guide them to the same value, or failing that , remove the system from the plex.

The act of syncing the STP and the 9037 to the same time ETR might/might not 
provide sufficient accuracy.

HTH,

<snip>
>That was what we originally though too, but our local IBM support 
>person told us we couldn't. Thinking further about configuration 
>activities to migrate to mixed CTN mode, I'm not seeing how on the non 
>STP capable processor we're going to be able to set the name of the 
>mixed CTN, since it isn't going to have the STP tab for that CEC,

I'm not sure that that matters. IIRC, the requirement is that all systems in 
the sysplex get their time from the same source. As long as the z10 gets it 
from the timers, and there's another CEC in the CTN getting it from the same 
timers and acting as the primary time server for the CTN, I believe that would 
work. 

z10 <- timer
zEC12 <- timer
 | Primary time server
\/ STP
other STP CECs

Before STP, there was no STP tab on the HMC and the CECs were able to 
participate in the sysplex by virtue of using the same timer. 

I *think* the migration would be to make the time source the timer connected to 
one zEC12, make that the PTS, then add the z10 pointing to the timer.

But I haven't read the fine manuals for some time, and it seems like the PTS 
becomes a sinle point of failure, unless at least one other machine in the CTS 
has a timer connection too. The point about the mixed mode CTN being envisioned 
as a fall-back situation, not an expected long-term situation is also good one. 
And if IBM is telling you "no", it's hard to argue that you'd want to try to do 
it. 
Scott
</snip>


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