In a message written on Sun, Oct 24, 2010 at 11:34:12AM -0400, Brandon Kim wrote:
From a service provider/ISP standpoint, does anyone think that having a local NTP server is really necessary?
Do you provide NTP to your customers? If you do there is probably an obligation there to make a reasonable effort to have accurate times. I'm not sure relying on random servers across the internet rises to that standard. I think you should have at least four clocks getting time not from the internet to compare. For instance, for a couple of thousand dollars you can get a Symmetricom appliance that will do GPS timing with analog dial backup to NIST. That gives you two non-internet sources at relatively low cost and low effort. Deploy four in different POP's and you have redundancy on your own network, and can market that you provide high quality NTP to your customers. It's nearly fire and forget, and a check for alarms from the box and make sure you watch for patches, that's about it. If you don't offer NTP to your customers whatever you need for your own internal logging is fine. Generally as long as they all sync to the same set of servers they will be accurate to each other, so you can compare times across servers. Set up 4 NTP servers, let them sync to the outside world, let all of your internal boxes sync to them. Notice in both cases I said deploy 4. If you understand the protocol, and in particular the decision process that really is the minimum number to have high quality NTP. Syncing everything to one or two NTP servers really doesn't work so well. -- Leo Bicknell - bicknell@ufp.org - CCIE 3440 PGP keys at http://www.ufp.org/~bicknell/