NTP Issue at 1 one of the CUCM Subscriber

[Suresh Hudda]

Dear Experts,

We are facing a NTP syncing issue at one CUCM subscriber at one of our customer.

CUCM version is 8.6.2 and Cisco switch is working as external ntp server cucm cluster.

CUCM Publisher showing synchronized with external ntp server (utils ntp status) with stratum value 6, but this (cucm pub) showing "test- ntp_stratum failed" when we do 'utils diagnose test' on it.

At 1 subscriber 'utils ntp status' showing synchronized with local ip address of it but not with publisher ip address and there is 5 minutes time difference due to this all Cisco IP Phones which are registered to this particular subscriber showing this 5 min time difference. But other 2 CUCM subscriber in this cluster have not any such issue.

Troubleshooting done..

1. Restarted ntp service at pub and problematic sub (utils ntp restart).

2. Re added ntp ip from CUCM pub and made the entry again.

3. Rebooted the problematic subscriber.

please suggest what else can be done to resolve this issue.

Suresh

[Ronak Agarwal]

Hi Suresh,

Pub stratum value should always be less than or equal to 3. You might want to change it.

Is the NTP server defined in OS admin, accessible? Please go to OS admin and check. If it is not, please correct that.

Please share the complete output of "utils ntp status" from all the nodes in the cluster.

Also share the name of the servers in the above IP address.

Are you getting any ntp related alerts on RTMT? If yes, please mention those.

What is the stratum value of external NTP server?

Regards,
Ronak Agarwal

[Suresh Hudda]

Hi Ronak,

Thanks for sparing time for this (+5)

startum value is seems to be good, actually 'stratum value 3 or less than it' means numerically it should be a greater value between (3 to 9).

NTP server is showing accessible from OS admin page of pub.

under 'utils ntp status' all nodes showing publisher IP and local IP both, but problematic subscriber'ntp pointing to its local IP.

On RTMT I have not seen any alert regarding to it.

Suresh

[Manish Gogna]

Hi Suresh,

I would suggest opening a TAC case since the basic checks have been done. The ntp config file on the subscriber might require to be corrected via root access.

HTH

Manish

[Suresh Hudda]

Thank you Manish, that's what I thought !!!

Actually issue is with network here, ntp packets/ack are not received back from publisher but publisher is sending those. PCAP helped to got to know this.

Suresh

[Ronak Agarwal]

Glad to hear that you have isolated the issue!!