ibaClock
Manual
Issue 1.4
55
16
NTP
Since NTP was developed for synchronization over long distances (wide area networks
= WANs), it does not place any particular requirements on the network infrastructure.
In the event of a synchronization via WANs, such as the Internet, NTP can be used to
achieve an accuracy of about 0.01 seconds. This can be increased to < 1 ms in local
networks (LANs).
Prior to Windows 10 1607 (anniversary update) and the Pendant Windows Server 2016,
however, only an accuracy of about 1-2 seconds could be achieved with the client inte-
grated in Windows. If a greater accuracy was required, third party clients had to be re-
sorted to.
With the above-mentioned Windows versions, the integrated client offers an accuracy of
up to 1 ms.
16.1
Functional principle
With NTP, there are primary servers (stratum 1) that are synchronized with a GPS re-
ceiver, for example. For the following, secondary, tertiary and other NTP servers, the
stratum value is always increased by one the lower they are in the synchronization struc-
ture.
NTP also offers a high level of reliability through redundant servers and network paths
as well as a self-organizing hierarchical network structure.
Figure 20: Failure of the connection between P1 and P2
As can be seen in figure 20, if a connection between P1 and P2 fails, then the structure
reorganizes itself and automatically assigns new strata.
The round-trip delay as well as the offset are determined similarly to with PTP, as the
following example shows.
