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New Member

Which Cisco router for NTP service


I'm looking for deploying NTP service for multi-customer (in Datacenter).


So, I take a look at Cisco routers list and I saw that some router doesn't have hardware-clock / internal-clock ; for example 2600 series.


I'm looking for a "cheap" but good solution to provide NTP :
- "Cheap" : that's why I take a look at routers, and not directly NTP appliance.

- "Good" : something that can provide time to 300+ end-devices.


Cisco 800 series got hardware-clock, if I read good. But this is the cheapest router, so I don't feel confident.

> What's the "best" router for NTP server ? 
> Please, could you share your experiences, opinions ?


Have a nice day.

Everyone's tags (3)
Hall of Fame Super Gold

No Cisco appliance or device

No Cisco appliance or device can keep time accurately.  All Cisco appliance will require regular SNTP/NTP synchronization.


Whether it's a router or a switch, the appliance need to get synchronization from the outside or you can get yourself a dedicated GPS-based NTP appliance.  


If you want a dedicated machine to do nothing but sync SNTP/NTP then a Cisco router or a switch is a very expensive option (unless you have spare available).  


In some cases, I have used a Raspberry Pi or a Beagle Bone Linux client to be the SNTP/NTP.  These clients go to the internet to get sync and all my Cisco kit synch to them.

Hall of Fame Super Silver

I think that we need a better

I think that we need a better understanding of what you are trying to achieve. If you are trying to achieve a highly accurate source of time then I agree with Leo that no Cisco device on its own has a sufficiently accurate clock to provide a highly accurate source of time over an extended period. But if you allow that Cisco device to learn time from an Internet NTP source then it can indeed supply highly accurate time to your customers.


But if you are looking for something that can keep 300 devices in sync about time, so that logs do correlate etc then many of the Cisco routers and switches could achieve that.





New Member

Thanks Leo & Richard ! The

Thanks Leo & Richard !


The needs is the following :

I got an highly accurate time from an Internet NTP and I want to distribute it to 300+ devices.

So, I decided to get 3750 switches to take the time from Internet and delivering it to 300+ devices. The problem is that 3750 doesn't have any internal-clock / hardware-clock. So, if 3750 switches lost their connection with Internet NTP. They will continue to increment the time from a software feature and not a hardware feature. That's mean the time will be not "highly" accurate.

So, I decided to take another kind of device : routers.

But, I don't know how to find the "cheapest" router that offer internal-clock / hardware-clock to ensure the accurate of time delivered by them (in case we lost internet ntp connection).

Cisco 800 series apparently got internal clock, could it do the job correctly ?


Thanks for your help!

Hall of Fame Super Gold

<pre __jive_macro_name="quote

Cisco 800 series apparently got internal clock, could it do the job correctly?

Rick and I have answered this question already.  


Depends on the router, you can instruct the router to regularly update the hardware clock using the command "ntp update-calendar".


If you really insist on a router, an 800 router, then you can get all your device to sync to your router and your router gets sync somewhere in the internet.


Make sure you have the following commands:  


ntp server <NTP server>

ntp update-calendar 


Note:  You can have multiple NTP server IP addresses.  And the command above are hyperlinks.


Warning:  DO NOT be tempted to use the command "ntp master".

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