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CUCM 9.x+ NTP expected behaviour in failover situation

Brett Hanson
Level 1
Level 1

Hi folks,

I've been trying to find out what the expected behaviour is for CUCM NTP in the event that the Publisher goes down and am not having any luck.

As the Publisher looks to the NTP server for time and the Sub looks to the Publisher for time, what happens when the Publisher is unavailable?

Does the Subscriber pick up the role of the Publisher and then look to the external source for NTP?

Cheers,

Brett

3 Accepted Solutions

Accepted Solutions

Chris Deren
Hall of Fame
Hall of Fame

No, time will simply be no longer synchronized and may or may not be slightly off.

HTH,

Chris

View solution in original post

davrojas
Level 3
Level 3

Hello Brett,

On the screenshot below you will see the output of the command 'utils ntp status' in a cluster lab of how the NTP status of the Subscriber server is when the Pub (192.168.1.120) goes down, usually when NTP is synched you will find that the reference id is the ip address of what was configured initially in the publisher as the NTP source as for example an NTP public address. As you can notice it remains in the state of .INIT. which means initialization has not yet succeeded.

Regards,

- |)avi|)

View solution in original post

Time will simply follow whatever is pulled from the Sub (SCCP phones) which may be slightly off. SIP phones pull the time from NTP references, which is typically pointed to the same NTP source as the PUB so I would assume is unavailable as well, whch means time might be off as well.

Chris

View solution in original post

6 Replies 6

Chris Deren
Hall of Fame
Hall of Fame

No, time will simply be no longer synchronized and may or may not be slightly off.

HTH,

Chris

Thanks Chris, rating given.

davrojas
Level 3
Level 3

Hello Brett,

On the screenshot below you will see the output of the command 'utils ntp status' in a cluster lab of how the NTP status of the Subscriber server is when the Pub (192.168.1.120) goes down, usually when NTP is synched you will find that the reference id is the ip address of what was configured initially in the publisher as the NTP source as for example an NTP public address. As you can notice it remains in the state of .INIT. which means initialization has not yet succeeded.

Regards,

- |)avi|)

Thanks David, rating given.

+5 to David and Chris..One thing I am curious to know is this: What happens to the time on the IP phones in a situation where the subscriber time is unsynchronized due to the publisher unavailability?

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Time will simply follow whatever is pulled from the Sub (SCCP phones) which may be slightly off. SIP phones pull the time from NTP references, which is typically pointed to the same NTP source as the PUB so I would assume is unavailable as well, whch means time might be off as well.

Chris