Why is Clock Set unstable?

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Nov 28th, 2007
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In my practice i realized that setting clocks always change to "a dead old time of 1993 i think this was the factory default" whenever i restart the router, even though the new "clock set" is saved to "startup"

Can anyone please help as to why this is happining and how to come about resolving it?

The command used was "clock set hh:min:sec MONTH DATE YY"

Thanks

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Kevin Dorrell Wed, 11/28/2007 - 05:30
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That is because your router does not have a real-time clock in it. It is simulated by the software, and loses its setting every time you reboot.


I know ... it's pretty poor, isn't it? The only way I know to resolve it is to use NTP.


Although, what do you mean even though the new "clock set" is saved to "startup"? What platform are you using?


Kevin Dorrell

Luxembourg


JORGE RODRIGUEZ Wed, 11/28/2007 - 05:31
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Olu, the seting time/date unfortunately is not saved in configuration , in most cases this is normally resolved by configuring network time protocol also known as NTP , in the event that you do not have an internal server that provides NTP information there are numerus public NTP server out in the internet where you can pooint your local NTP servers to sync up with public NTP servers, do a search on google for public NTP once you get some of this information then you don't have to use anymore clock set but point your device to NTP servers to pool time date information onto your router or switch.


Configuring NTP on CATOS devices

http://www.cisco.com/en/US/docs/switches/lan/catalyst4000/7.3/configuration/guide/ntp.html#wp1019819


On IOS

http://www.cisco.com/en/US/docs/switches/lan/catalyst4840g/12.0_13_wt6_1/configuration/guide/4840ntp.html#wp1023829



pls rate any helpful post if it helps!

HTH

Jorge


insccisco Wed, 11/28/2007 - 10:02
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Every time I do "ntp server IP-address", it is successfull. Then I change my time to the correct time and all good.


However, 1 or 2 minutes later, the time changes to 5 hours ahead.


I have a 2950 switch and I am located in the New York area.


My NTP statements are:


ntp clock-period 17180077

ntp server 209.51.161.238



What is going on?

JORGE RODRIGUEZ Wed, 11/28/2007 - 11:35
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need to configure time zones


e.g


Im in Boston and my routers have


e.g


clock timezone est -5

clock summer-time est recurring



and our routers read the exact time 2:32PM


cisco-2811-rtr#show clock

14:32:29.839 est Wed Nov 28 2007



here is some info for time zones

http://www.cisco.com/en/US/docs/ios_xr_sw/iosxr_r3.2/system_management/command/reference/yr32clck.html




pls rate any helpfull posts !


HTH

Jorge




ohassairi Thu, 11/29/2007 - 01:40
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Some platforms have a hardware clock that is separate from the software clock. In Cisco IOS software syntax, the hardware clock is called the "calendar." The hardware clock is a battery-powered chip that runs continuously, even if the router is powered off or rebooted. After you set the hardware clock, the software clock will be automatically set from the hardware clock when the system is restarted or when the clock read-calendar EXEC command is issued. The time specified in this command is relative to the configured time zone.

Kevin Dorrell Thu, 11/29/2007 - 01:53
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ohassairi,


That is very useful to know. Do you know which platforms have that feature? Is it only the really top end?


I reckon the feature should be built into everything. If it is built into my bedside alarm clock, how can it be too expensive to build into a router?


Kevin Dorrell

Luxembourg


JORGE RODRIGUEZ Thu, 11/29/2007 - 05:18
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Ohassairi , I echo Kevin statement.. indeed useful info,question remains why feature is available on some platforms and not on others , Hmmm... perhaps cisco can throw some commens..


Jorge

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