On 10/24/2010 7:37 PM, Peter Lothberg wrote: >> acquired the time from the three stratum-1 clocks, they all poll each other >> for the average. > > How many clocks/servers do you need to average from to knew that you > are within say 1ms of UTC(nist)?
What type of evidence model do you need to prove this with? - The NIST servers located around the US are mostly operated out of people like our operations (we have seven of them now and Atlanta coming online in about three weeks as well.) NTP has some foibles most are probably unaware of - that is it must have three (3) competent sources defined so that it can vote. We like to also say all three voices need to be coming from the same subnet so that the network latency and other physical aspects which control the policy-implementation are reliable as well. If you take one server from multiple sites you will be stuck with multiple network latency overhead factors polluting the resolution and certainty in the 'small bits' of your time-attestation. The real issue is how you prove the time-setting took. Or better yet - that you allow Applications to make their own NTP queries of reference time servers - that's really where the rubber meets the road in time-centric trust models. Todd Glassey > > -P > > -- //----------------------------------------------------------------- This message may contain confidential and/or privileged information. If you are not the addressee or authorized to receive this for the addressee, you must not use, copy, disclose or take any action based on this message or any information herein. If you have received this message in error, please advise the sender immediately by reply e-mail and delete this message. Thank you for your cooperation.
