If your application is so critical that NTP timing loss causes disaster and your holdover fails in less than a day and you aren't generating your own via gps, you are incompetent, full stop
If your application is so critical that NTP timing loss causes disaster and your holdover fails in less than a day and you aren't generating your own via gps, you are incompetent, full stop
And if things are that critical, you might have other references besides just GPS...
E.g.,
* https://www.meinbergglobal.com/english/products/