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Knowledge Base

The S5700 Fails to Synchronize the Clock Through NTP

Publication Date:  2019-05-20  |   Views:  1542  |   Downloads:  0  |   Document ID:  EKB1100015806

Contents

Issue Description

The S5700 fails to synchronize the clock of the u2000D through NTP.

Handling Process

1. Run the display clock command. The result shows that it is not synchronized with current China Standard Time.

   =================================================

   2018-05-11 02:01:32-05:13

   Friday

   Time Zone(Indian Standard Time) : UTC-05:13

 

2. Run the display ntp-service event clock-unsync command to check the reason about the clock synchronization failure. The reason is "Clock selection failed - No selectable clock." The details are as follows:

  <TY-XZX-CE01-S5700>disp ntp-service event  clock-unsync 

    1. Clock source   : 10.86.X.X

      Session type   : client, configured

      Unsync reason  : Clock selection failed - No selectable clock

      Unsync time    : 2018-05-11 01:25:26-05:13

 

    2. Clock source   : 10.86.X.X

      Session type   : client, configured

      Unsync reason  : Clock selection failed - No selectable clock

      Unsync time    : 2018-05-11 01:35:08-05:13

 

3. Check the logbuffer log. There are duplicate logs about system synchronization source loss.

   May 11 2018 01:54:26-05:13 TY-XZX-CE01-S5700 %%01NTP/4/SOURCE_LOST(l)[0]:System synchronization source lost. (SourceAddress=10.86.X.X, Reason=Clock selection failed - No selectable     clock)

   May 11 2018 01:53:21-05:13 TY-XZX-CE01-S5700 %%01NTP/4/STRATUM_CHANGE(l)[1]:System stratum changes from 16 to 3. (SourceAddress=10.86.X.X.)

   May 11 2018 01:53:21-05:13 TY-XZX-CE01-S5700 %%01NTP/4/LEAP_CHANGE(l)[2]:System leap changes from 3 to 0 after clock update.

   May 11 2018 01:53:21-05:13 TY-XZX-CE01-S5700 %%01NTP/4/PEER_SELE(l)[3]:The peer selected by the system is 10.86.X.X.

   May 11 2018 01:44:50-05:13 TY-XZX-CE01-S5700 %%01NTP/4/SOURCE_LOST(l)[4]:System synchronization source lost. (SourceAddress=10.86.X.X., Reason=Clock selection failed - No selectable     clock)

 

4. The debugging ntp-service all command output shows that the synchronization distance is greater than the distance threshold. As a result, the synchronization loss occurs.

  May 11 2018 02:28:52.50.2-05:13 TY-XZX-CE01-S5700 NTP/7/NTP_DBG_Selection:

  FileId [ 019 ], LineNo [ 00536 ]- Server 10.86.x.x not considered for clock selection. (Reason: Synchronization distance greater than distance threshold. (Current: 3.95522,

  Allowable: 1.00048))

 

Root Cause

The synchronization distance is greater than the distance threshold. As a result, the synchronization loss occurs.

Solution

1. When the windows server2003/2008 or Windows 7 system functions as the NTP server, change the value of LocalClockDispersion in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\W32Time\Config of the registry of the NTP server.

Run the ntp-service max-distance command to set the maximum NTP synchronization distance threshold to 16.

Suggestions

If the clock source of the Windows server is too large, the time of the device is not synchronized with that of the PC.

You can try the following methods:

When the windows server2003/2008 or Windows 7 system functions as the NTP server, the default NTP time offset is 10 seconds. You can perform the following operations:

1. Change the value of LocalClockDispersion in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\W32Time\Config of the registry of the NTP server from 10 to 0.

2. Run w32tm /config /update in the command window of the NTP server to restart the NTP service.

After the preceding modification, the NTP server offset is within the range specified in the protocol, and the NTP client can be synchronized to the NTP server.