NTP servers

[jchan@directv.com]

Can I have a log whenever Prefer NTP server is off few seconds compare with backup NTP server ?

How long it take to NTP failover when the NTP prefer is not available ?

How long does it take to failback when the NTP prefer is back online ?

Thanks in advance

Johnson

[Philip D'Ath]

Ideally you should have four NTP servers configured to resolve the Two Generals issue.

https://en.wikipedia.org/wiki/Two_Generals%27_Problem

If you comply with this system, it doesn't really matter about short NTP server outages or errors.

[evan.r.moore]

I follow the general problem, but don't see why 4 is the solution.

[Philip D'Ath]

4 is the minimum number of servers to be able to recover from one server giving bogus or wrong time.

[xthuijs]

if timing is important to you, whether it be freq or TOD, maybe using a GPS receiver on a few designated locations is an option and pull them into your (core) routers. from there on distribute the time through the network.

Nothing beats a stratum-0 (satellite) TOD/clock!

Concept being that you take the gps TOD (and freq) and distribute the time via ntpv4.

So the set of devices with gps receiver are both client to the gps, but server to the rest of your network. Is that something to consider?

xander