why the NTP client NE40E can't synchronize to the NTP server SYNLOCK T6020

Product: NE40E
Software version: V600R008C10SPC300
NTP server:SYNLOCK T6020 Huawei BITS
NTP client:NE40E Huawei router
Problem: When we configure ntp on the ntp client NE40E, the ntp status is unsynchronized,but the route is reachable.

<NE>display ntp-service status

clock status: unsynchronized

clock stratum: 16

reference clock ID: none

nominal frequency: 100.0000 Hz

actual frequency: 100.0000 Hz

clock precision: 2^17

clock offset: 0.0000 ms

root delay: 0.00 ms

root dispersion: 0.00 ms

peer dispersion: 0.00 ms

reference time: 00:00:00.000 UTC Jan 1 1900(00000000.00000000)

<NE>display ntp-service sessions verbose

clock source: 10.1.1.1(OM)

clock stratum: 16

clock status: configured, insane, valid, unsynced

reference clock ID: 0.0.0.0

local mode: client, local poll: 1024, current poll: 1024

peer mode: unspec, peer poll: 1024, now: 426739

offset: 0.0000 ms, delay: 0.00 ms, disper: 0.00 ms

root delay: 0.00 ms, root disper: 0.00 ms

reach: 0, sync dist: 10.401, sync state: 0

precision: 2^17, version: 3, peer interface: wildcard

reftime: 00:00:00.000 UTC Jan 1 1900(00000000.00000000)

orgtime: 00:00:00.000 UTC Jan 1 1900(00000000.00000000)

rcvtime: 00:00:00.000 UTC Jan 1 1900(00000000.00000000)

xmttime: 13:21:35.175 UTC Dec 20 2017(DDE4E25F.2CD79D0A)

filter delay :  0.00   0.00   0.00   0.00   0.00   0.00   0.00   0.00

filter offset:  0.00   0.00   0.00   0.00   0.00   0.00   0.00   0.00

filter disper: 16.00  16.00  16.00  16.00  16.00  16.00  16.00  16.00

autokey flags: 0x0

autokey identity scheme used: none

Following the Revelation of failure <the NTP Clock Status Is Unsynchronized>:

1.Check whether the NTP client and server can ping through each other(the route is reachable);

2.Check whether the NTP authentication configuration on the client and server is correct(the configuration is correct);

3.Check whether the server is enabled with the NTP server function (the address of the NTP client configured on the ntp server T6020);

4.Check whether the NTP maximum synchronization distance of the client is greater than the root departure distance;

NTP is still unsynchronized when we have done all the above checks.

And then we check the clock of NTP client,the output is below:

<PH-SJN001-P1>display clock
2017-12-20 22:01+08:00
Thursday
Time Zone(UTC) : UTC+08:00

We found that NTP client time and NTP server time vary widely, the NTP server time is 2017-12-20 22:01, the missdistance is 8 hours.

so we change the date-time of NTP client close to the NTP server.

<NE>clock datetime 22:02:00 2017-12-20

after few minutes later, when the NTP synchronize again, the status of NTP is synchronized.

Root cause:

The configuration of datetime of NTP client NE40E is incorrect,the NTP client datetime exceeds the NTP server datetime by more than 3000s. Due to the protection mechanism of the NTP server, the NTP server can not synchronize with the NTP client.

Solution:

When the difference between the NTP client time and the NTP server time is too long, you can change the NTP client time to the time near the NTP server by using the following commands:

clock datetime [ utc ] time date

Suggestion:

From this issue, we can find that the configuration of datetime of NTP client NE40E is incorrect,when customer set datetime, just change the time zone, did not change the time.So when we configure datetime, we must confiugre correct time zone and datetime. When we find the NTP is unsynchronized, we can follow the Handling Process deal with it.