NTP and the Time Offset command line

[eastcoast10]

We recently installed signaling servers [a redundant pair] on an Option 61C so we are now officially a CS1000m.

We also activated NTP and that is working fine. When they implemented the solution our vendor indicated that the PBX goes to the signaling servers once a day to pick up clocking. The signaling servers then go to an external NTP source.

Looking at the NTP configuration in the PBX and on Element Manager that does appear to be the case.

> prt ntp
Primary IP Address: 10.90.12.20 [primary signaling server]
Primary Key ID: 0
Secondary IP Address: 10.90.12.21 [secondary signaling server]
Secondary Key ID: 0
Minimum Threshold: 1
Warning Threshold: 6
Maximum Threshold: 16
Security Mode for Primary: INSECURE
Security Mode for Secondary: INSECURE
Time Interval and Offset: 24 30
Synchronization Status: ACTIVE
Mode of Synchronization: BACKGROUND
UTC Offset: -5:00
Mode of communication: CS

My question is around what command line configures the PBX to go to the signaling server once a day, and when does it do that? I find that the PBX's own clock drifts about 15 seconds through the day. If the PBX got its clock signal at 7:00 AM in the morning before the call centre opens there would be very little drift between PBX and computer time.

Looking at the NTP configuration I assume that the "Time Interval and Offset" line is the command line that does that function. Looking at this line I assume my current settings mean

Time Interval and Offset: 24 30 // 24 means looks for clock once every 24 hours. 30 means it goes to the clock source 30 minutes after its nightly routine.


I have yet to come across any product documentation that gives the full syntax of this command, or suggests what other command you must use to set how many times a day the pbx looks to refresh its clock and when it does so.


I welcome your suggestions.

 

[bignose21]

So the NTP config in element manager does what it says it configures Linux elements. So in Element manager there is a box for all linux servers (Usually just a list of Sig Servers). Then you choose one as a Primary Clock Server and one a Secondary Clock Server. You can then add upto 10 External NTP servers below that.

So the Primary Clock server uses the external servers for reference (if there is any)
the secondary uses first choice the primary then the external servers
all other Sig Servers use Primary then Secondary

The Call Server should be setup Primary the Secondary Sig Server as it looks like you have. As the Callserver is VxWorks this is not setup by the Element Manager just setup in LD 117. See the Maintenance Input Output Guide for commands, the one you were after is:


CHG NTP TIMEINT <time_int> <offset> Configure both the time interval for background NTP synchronization and the time offset from other background routines.

This cannot be altered while the NTP is enabled so you would need to

STOP NTP BACKGROUND
DIS NTP
CHG NTP TIMEINT <time_int> <offset>
ENL NTP
SYNC NTP BACKGROUND

 

[eastcoast10]

Thanks

I have a further question on this. I have assumed the offset is an offset from your nightly routine. In our case the nightly routine begins at midnight. I therefore conclude that the offset is 30 minutes after the nightly routine or at 12:30 AM.

Is that the reference point for the offset parameter. Is the offset linked to your nightly routine?

 

[guycable2]

I would just set the time_int to 1 then it will check once every hour and you will not have any drift. We have changed all of our sites with AACC at them to check every hour and then any of our other CS1000 systems have been changed to 12 so they check twice per day.

I believe you are right about the 30 minutes after midnights but I can't confirm either.

 

[bignose21]

From the Freatues NTP

Background mode of synchronization
In background mode, the Call Server queries the NTP server at regular time intervals, as
specified in LD 117 or Element Manager. When using background mode, you must also specify
an offset value (in minutes) by which NTP avoids interfering with other scheduled background
routines.

So the answer is yes Offset from daily routine