Nokia IPSO 4.0 Reference Manual page 477

10. (Optional) Enable the NTP reference clock by clicking Yes in the NTP Master field.
Note
Only enable the NTP reference clock if you cannot reach an NTP server.
11. Click Apply.
The Stratum and Clock source fields appear. By default, the Stratum value is 1, and the
Clock source is set to Local Clock. Nokia recommends that you keep these defaults.
12. Click Save to make your changes permanent.
Nokia Network Voyager for IPSO 4.0 Reference Guide 477