other higher stratum servers. If a peer loses all reference clocks or fails, the other peers continue
to provide time to other clients on the network.
NTP Servers at the same Stratum level
If SecureSync is configured to obtain time from other NTP Servers at the same Stratum level
(i.e., NTP Peers) but is currently using a different input reference as its selected reference,
SecureSync will report to the network (via the NTP time stamps) that it is a Stratum1 time server.
Should, however, all input references except the other NTP server (s) become unavailable,
SecureSync will then drop to a Stratum2 time server (with System Time being derived from the
NTP time packets being received from the other NTP Peers.
NTP Servers at a higher Stratum level
If SecureSync is configured to obtain time from another NTP Server at a higher Stratum level
(i.e., NTP Servers), and it is using that NTPServer as its selected reference, SecureSync will
report to the network (via the NTP time stamps) that it is one less Stratum than its selected ref-
erence NTP Server.
E X A M P L E :
If SecureSync is configured to receive time from one or more Stratum1 NTP Servers, with no other
higher priority input references available, SecureSync will report to the network that it is a Stratum2
Server.
In order for SecureSync to use other NTP servers as a valid time reference to synchronize the
System Time, the input Reference Priority Setup table must be configured to allow NTP as an
available reference. For more information on the input Reference Priority table, refer to "Con-
figuring Input Reference Priorities" on page163.
Holdover
If SecureSync is synchronized to another NTP Server or reference, and that server or reference
subsequently loses sync or becomes unavailable (with no other higher priority input references
being present and valid), SecureSync will then go into the Holdover mode. It will remain in Hol-
dover mode until any enabled and valid input reference becomes available again, or until the
Holdover period expires, whichever occurs first.
During Holdover mode, NTP will remain at the same Stratum level it was before entering the
Holdover mode and can continue to be the reference to the network. However, if no input ref-
erence becomes available before the Holdover period expires, Time Sync will be lost and
shortly thereafter, NTP will report to the network that it is now at Stratum15. A status of
Stratum15 will cause the network to ignore SecureSync as an NTP time reference.
For more information about Holdover, see "Holdover Mode" on page210.
2.14 Configuring NTP
CHAPTER 2 • SecureSync User Reference Guide Rev. 26
105
To Next Page
Loading...
Need help?
General
