Types of Logs

Displays log entries for the Timing System, for example:

• The Unit has Rebooted: NetClock was either rebooted or power cycled.
• In Holdover: Input references were available, but all input references have since been lost. If the references are not restored before the Holdover period expires, time sync will be lost.
• No longer in Holdover: Input references were lost at one point (or declared not valid), but have since been restored OR the Input references were not restored before the Holdover period expired (Time Sync alarm is asserted).
• In Sync: NetClock is synchronized to its selected Time and 1PPS reference inputs.
• Not In Sync: NetClock is not synchronized to its Time and 1PPS inputs and is not currently in Holdover. NTP will indicate to the network that it is Stratum 15 and so the time server likely be ignored as a time reference.
• Frequency Error: The oscillator’s frequency was measured and the frequency error was too large. Or, the frequency couldn’t be measured because a valid input reference was not available.
• Reference change: NetClock has selected a different Time and 1PPS input reference for synchronization. Either the previously selected input reference was declared not valid (or was lost), so a lower priority reference (as defined by the Reference Priority Setup table) is now selected for synchronization OR a valid reference with higher priority than the previous reference is now selected for synchronization.

EXAMPLE:

GNSS is the highest priority reference with IRIG input being a lower priority. NetClock is synced to GNSS and so GNSS is the selected reference. The GNSS antenna is disconnected and IRIG becomes the selected reference. The Reference change entry is added to this log.

Displays log entries for authentication events (e.g., unsuccessful login attempts, an incorrectly entered password, etc.) that are made to NetClock’s command line interfaces (such as the front panel setup port, telnet, SSH, FTP, etc.).

Displays log entries related to GNSS reception status changes, Sync/Holdover state changes, SNMP traps being sent, etc. Examples include:

• Reference Change: NetClock has switched from one input reference to another (for example, IRIG was the selected input being used, but now GNSS is the selected reference).
• GPS Antenna Problem: The GPS Antenna Problem alarm indicates the GNSS receiver has detected an over-current or undercurrent condition (an open or short exists in the GNSS antenna cable, or the GNSS antenna is not connected to NetClock). The receiver will attempt to continue the normal acquisition and tracking process regardless of the antenna status. The current draw measurements that will indicate an antenna problem are:
  • Under-current indication < 8 mA
  • Over-current indication > 80 mA

Note: This alarm condition will also be present if a GNSS antenna splitter that does not contain a load to simulate an antenna being present is being used.

• GPS Antenna OK: The antenna coax cable was just connected or an open or short in the antenna cable was being detected but is no longer being detected.
• Frequency Error: The oscillator’s frequency was measured and the frequency error was too large. Or, the frequency couldn’t be measured because a valid input reference was not available.
• Frequency Error cleared: The Frequency Error alarm was asserted but was then cleared.
• In Holdover: Input references were available, but all input references have since been lost. If the references are not restored before the Holdover period expires, time sync will be lost.
• No longer in Holdover: Input references were lost at one point (or declared not valid), but have since been restored OR the Input references were not restored before the Holdover period expired (Time Sync alarm is asserted).
• In Sync: NetClock is synchronized to its Time and 1PPS inputs.
• Not In Sync: NetClock is not synchronized to its Time and 1PPS inputs and is not currently in Holdover. NTP will indicate to the network that it is Stratum 15 and so the time server likely be ignored as a time reference.
• Sending trap for event 1 (SNMPSAD): An SNMP trap was sent by the SNMP agent to the SNMP Manager. The event number in this entry indicates which SNMP trap was sent.
• The Unit has Rebooted: NetClock was either rebooted or power cycled.

Displays log entries created for all configuration changes that have occurred (such as creating a new user account, for example).

The NTP log displays operational information about the NTP daemon, as well as NTP throughput statistics (e.g., packets/sec.). Examples for entries in this log include indications for when NTP was synchronized to its configured references (e.g., it became a Stratum 1 time server), as well as stratum level of the NTP references.

The NTP throughput statistics data can be utilized to calculate mean values and the standard deviation.

Example log entries include:

• Synchronized to (IP address), stratum=1: NTP is synchronizing to another Stratum 1 NTP server.
• ntp exiting on signal 15: This log entry indicates NTP is now indicating to the network that it is a Stratum 15 time server because it is not synchronized to its selected reference.
• Time reset xxxxx s: These entries indicate time corrections (in seconds) applied to NTP.
• No servers reachable: NTP cannot locate any of its configured NTP servers.
• Synchronized to PPS(0), stratum=0: NTP is synchronized using the PPS reference clock driver (which provides more stable NTP synchronization).

Displays log entries related to oscillator disciplining. Provides the calculated frequency error periodically while synchronizing to a reference.

If NetClock is connected to a GNSS antenna and is tracking satellites, this log contains a running hourly count of the number of GNSS satellites tracked each hour. This history data can be used to determine if a GNSS reception problem exists and whether this is a continuous or intermittent reception issue.

GNSS reception may be displayed as cyclic in nature. A cyclic 12 hour pattern of decreased GNSS reception typically indicates that the GNSS antenna has an obstructed view of the horizon. The GNSS satellites are in a 12-hour orbit, so if part of the sky is blocked by large obstructions, at the same time every day (at approximately 12 hour intervals), the GNSS reception may be reduced or may vanish altogether. If this occurs, the antenna should be relocated to afford it an unobstructed view of the sky.

Every hour (displayed in the log as UTC time), NetClock counts the total number of satellites that were tracked during that hour. The GNSS qualification log shows the number of satellites that were tracked followed by the number of seconds that the particular number of satellites were tracked during the hour (3600 seconds indicates a full hour). The number to the left of the “=” sign indicates the number of satellites tracked and the number to the right of the “=” sign indicates the number of seconds (out of a total of 3600 seconds in an hour) that the unit was tracking that number of satellites. For example, “0=3600” indicates the unit was tracking 0 satellites for the entire hour, while “0=2700 1=900” indicates the unit was tracking one satellite for 900 seconds, but for the remaining portion of the hour it was tracking zero satellites.

Every hourly entry in the log also contains a quality value, represented by “Q= xxxx” (where x can be any number from 0000 through 3600). The Qualification log records how many satellites were tracked over a given hour. If for every second of the hour a tracked satellite was in view, the Quality value will equal 3600. For every second NetClock tracked less than the minimum number of satellites, the value will be less than 3600. The minimum requirement is one satellite at all times after the unit has completed the GNSS survey and indicates “Stationary”. A minimum of four satellites are required in order for the GNSS survey to be initially completed.

If all entries in the qualification log are displayed as “0=3600”, a constant GNSS reception problem exists, so the cause of the reception issue is continuous. If the unit occasionally shows 0=3600 but at other times shows that 1 through 12 have numbers of other than “0000”, the reception is intermittent, so the cause of the reception issue is intermittent. If the Quality value normally equals 3600 but drops to lower than 3600 about every 12 hours, the issue is likely caused by the GNSS antenna having an obstructed view of the sky.

Example GPS Qualification Log Entry:

6 = 151 7 = 1894 8 = 480 9 = 534 10 = 433 12 = 108 Q = 3600

In this example, NetClock tracked no less that 6 satellites for the entire hour. Out of the entire hour, it was tracking 6 satellites for a cumulative total of 151 seconds (not necessarily in a row). For the duration of the hour, it was tracking, 7, 8, 9, 10 and 12 satellites for a period of time. Because it was tracking at least at least one satellite for the entire hour, this Quality value is Q=3600.

Note: If NetClock is not connected to a GNSS antenna, this log will remain empty.

Displays log entries related to the Timing System events and daemon events (such as the Alarms, Monitor, Notification, or SNMP daemons starting or stopping, etc.)

Displays log entries related to Input reference state changes (for example, IRIG input is not considered valid), antenna cable status. Examples include:

• GRGR = GNSS Reference^{1GR = GNSS Reference} antenna fault: The GNSS Antenna Problem alarm indicates the GNSS receiver has detected an over-current or undercurrent condition (an open or short exists in the GNSS antenna cable, or the GNSS antenna is not connected to NetClock). The receiver will attempt to continue the normal acquisition and tracking process regardless of the antenna status.
• GR antenna ok: The antenna coax cable was connected at this time or an open or short in the antenna cabling was occurring but is no longer being detected.

Displays log entries related to software updates that have been performed.