WESTERSTRAND CIRCLE LINE NTP User Manual page 16

DOK11108en02
2023-03-31
16 (28)
Trap type: This function is used to choose SNMP trap version.
Trap type v1 = Trap according to SNMPv1
Trap type v2 = Trap according to SNMPv2
NTP
NTP settings
General Description
Westerstrand NTP Clients has several features to achieve a reliable and accurate time. The
configuration of the different facilities is flexible, and the features can be selected or deselected
depending on each customer's individual needs.
As an NTP Client the unit has three different ways to determine the most accurate and reliable
candidates to synchronize the system clock. Which model that is used depends on the specific
installation and the customer requirements. The NTP client has also a server list where up to 5
different time servers can be entered.
The three different ways are:
1. FIRST Always use the first server in the list if available. If not available, take the next one.
This suits installations where it is more important to know exactly from where the clients get time
than to have the most accurate time. The other NTP servers in the list will then be more of backup
servers.
2. STRATUM Use the NTP server with best stratum. The software sends a request to all servers in the
list and uses the time from the one with best stratum. If same stratum it will use the one that is first
in the server list.
This suits installations where it is important that the time is coming from a time server high up in the
pyramid.
3. MEDIAN Send a request to all servers in the list and use the median value (the NTP server that is in
the middle). This will filter out all misleading time messages.
In addition to these rules there are some more features such as synchronization limits and a clock
discipline algorithm is also included. This algorithm measures the oscillators drift over a longer period
and makes compensations for the drift.