Document for Cisco router reset clock after reload

Unanswered Question
Jan 13th, 2010

Hi all,

Have the document or relate link about the clock was reseted when router reload ?


I have this problem too.
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Ganesh Hariharan Wed, 01/13/2010 - 21:43


You will always lose the clock when you do a reboot.You'll need to set up some sort of NTP server, or use an NTP server out on
the net.You could also use another router as an NTP server,The clock will alwayas reset  to 1993 when routers reboot.

I would suggest better to configure NTP in your network.

Hope that helps out your query !!



Decho.datacraft Wed, 01/13/2010 - 22:32


Cisco have any documents or link that identifies about this topic?

Thanks all for reply and guide me

milan.kulik Thu, 01/14/2010 - 07:43



Some platforms have a hardware clock (calendar) in addition to a software clock. The hardware clock is battery operated, and runs continuously, even if the router is powered off or rebooted.

If the software clock and hardware clock are not synchronized, and the software clock is more accurate, use this command to update the hardware clock to the correct date and time.

To perform a one-time update of the hardware clock (calendar) from the software clock, use the clock update-calendar command in user EXEC or privileged EXEC mode.

So some routers should provide a hardware clock (calendar).

An example is XR 12000, see

But I have not found a complete list of such routers.




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