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New Member

CUCM 9.x+ NTP expected behaviour in failover situation

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
Hall of Fame Super Silver

CUCM 9.x+ NTP expected behaviour in failover situation

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

HTH,

Chris

Silver

CUCM 9.x+ NTP expected behaviour in failover situation

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|)

Hall of Fame Super Silver

CUCM 9.x+ NTP expected behaviour in failover situation

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

6 REPLIES
Hall of Fame Super Silver

CUCM 9.x+ NTP expected behaviour in failover situation

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

HTH,

Chris

New Member

CUCM 9.x+ NTP expected behaviour in failover situation

Thanks Chris, rating given.

Silver

CUCM 9.x+ NTP expected behaviour in failover situation

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|)

New Member

CUCM 9.x+ NTP expected behaviour in failover situation

Thanks David, rating given.

VIP Super Bronze

CUCM 9.x+ NTP expected behaviour in failover situation

+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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Hall of Fame Super Silver

CUCM 9.x+ NTP expected behaviour in failover situation

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

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