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New Member

Time Synchronization

Hello,

I apologize If I'm posting this in the wrong place.

I'm looking for ideas or best practices on how to achieve the following.

We have Cisco routers,switches and HP switches and I'm trying to get all of their time stamps to by synched up. Do folks point them to a NTP server not even sure if this is possible yet or someother way.

Thanks in advance.

Derek

4 REPLIES
Hall of Fame Super Gold

Re: Time Synchronization

Do folks point them to a NTP server not even sure if this is possible yet or someother way.

NTP or SNTP is the best solution.

There are so many ways to do this.

What I do in our network is get the core routers to point to a series of dedicated NTP sources in our country.  I do not point our core routers to a pool.

Our distro points to our core routers and all our access switches point to our distro.  All our CUCM and WLC point to our distro.

NTP bandwidth and utilization is cheap.  But I still want as few network devices as possible going out to the network.

You can configure numerous NTP/SNTP IP addresses and the appliance will just pick and choose one in random.

If you don't want anything to go out to the internet then you can purchase a GPS-based NTP server.  I would recommend you not entertain a solution that is NOT GPS-based because this means that the appliance or solution still has to go to the Internet to get synch, which any Raspberry Pi can do with relative ease and will plainly set you back $45. 

New Member

Time Synchronization

Thanks for the fast response. We do use a DC currently and point pc's and PBX's to this one location. I just wasn't sure if point all the routers and switches to this server is best practice. We are spread out some but not across time zones yet just around a few states. I did read the Cisco white paper on NTP and that really just produced more questions then answers for me.

Thanks,

New Member

Time Synchronization

I came across the following and it made sense so I thought I would share and let others tell me if this is a good practice.

Have 2 internal NTP servers going out two different Internet connections going to two different external NTP servers. Then the 2 internal NTP servers peer of each other incase one of them looses connection to their external NTP server. Then point all devices to use both internal NTP servers incase one fails. This brings a few questions to mind. Would I at site A just send the Router to the internal NTP and have the switch(s) come to the router for NTP request or send both router and switch(s) to both internal NTP servers? Since the routers/switches are going to internal NTP do I need to still setup ACL somehow for those devices?

Thanks,

Hall of Fame Super Gold

Time Synchronization

Have 2 internal NTP servers going out two different Internet connections going to two different external NTP servers. Then the 2 internal NTP servers peer of each other incase one of them looses connection to their external NTP server.

Why have each NTP servers point to just two NTP servers over the internet?  I'd stick as many as I can (stratum 1, mind you) and let your NTP servers decide which one they want to use.  Ok, ok, ok.   Maybe I'm blowing things up.  I'd say configure up to six (6) internet NTP servers.  The same six is configured to both of your NTP server. 

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