nanog mailing list archives
Re: NTp sources that work in a datacenter (was Re: Is latency equivalent to RTT?)
From: Joel Jaeggli <joelja () darkwing uoregon edu>
Date: Wed, 14 May 2003 08:13:12 -0700 (PDT)
On Wed, 14 May 2003, Steve Francis wrote:
Michael.Dillon () radianz com wrote:I assume that it's fairly common for people to have Solaris or Linux boxes in every PoP to do measurements. In that case, the difficulty isn't in measuring one-way latency, it's in synchronizing the time on all the servers. And with fairly cheap GPS and CDMA clocks that is a lot easier/cheaper than it once was.But what GPS clock can you install in a datacenter? AFAIK, they all require roof (or at least window) access in order to install the antenna. (At least, all the GPS based ntp servers I've looked at do). Is that not true of CDMA servers?
cdma recievers require a visible cdma signal so if your cdma phone works in the datacenter the cdma reciver will as well...
How have others solved this issue? (Short of owning their datacenters.)
Ask/pay/rent for roof access for the antenna, it's not large but it does work better with an unobstructed video of the sky. There's also the question of how many stratum=1 time sources a given datacenter needs. if there's someone else with one it should be fairly unintrusive to share. Also if you just need a high level of syncronization between the time on all your hosts you can just deploy one standalone ntp server, sync it against public time sources and get everything synced against that. its probably a 95% solution to most people's timeing needs. -- -------------------------------------------------------------------------- Joel Jaeggli Academic User Services joelja () darkwing uoregon edu -- PGP Key Fingerprint: 1DE9 8FCA 51FB 4195 B42A 9C32 A30D 121E -- In Dr. Johnson's famous dictionary patriotism is defined as the last resort of the scoundrel. With all due respect to an enlightened but inferior lexicographer I beg to submit that it is the first. -- Ambrose Bierce, "The Devil's Dictionary"
Current thread:
- Is latency equivalent to RTT? Michael . Dillon (May 14)
- Re: Is latency equivalent to RTT? Stephen J. Wilcox (May 14)
- Re: Is latency equivalent to RTT? Andrew Bangs (May 14)
- Re: Is latency equivalent to RTT? John Kristoff (May 14)
- Re: Is latency equivalent to RTT? Henk Uijterwaal (RIPE-NCC) (May 14)
- Re: Is latency equivalent to RTT? Barney Wolff (May 14)
- <Possible follow-ups>
- Re: Is latency equivalent to RTT? Michael . Dillon (May 14)
- NTp sources that work in a datacenter (was Re: Is latency equivalent to RTT?) Steve Francis (May 14)
- Re: NTp sources that work in a datacenter (was Re: Is latency equivalent to RTT?) Henk Uijterwaal (RIPE-NCC) (May 14)
- Re: NTp sources that work in a datacenter (was Re: Is latency equivalent to RTT?) Joel Jaeggli (May 14)
- Re: NTp sources that work in a datacenter (was Re: Is latency equivalent to RTT?) Sean Donelan (May 14)
- Re: NTp sources that work in a datacenter (was Re: Is latency equivalent to RTT?) just me (May 14)
- NTp sources that work in a datacenter (was Re: Is latency equivalent to RTT?) Steve Francis (May 14)
- Re: NTp sources that work in a datacenter (was Re: Is latency equivalent bmanning (May 14)
- Re: NTp sources that work in a datacenter (was Re: Is latency equivalent to RTT?) David G. Andersen (May 14)
- Re: NTp sources that work in a datacenter (was Re: Is latency equivalent to RTT?) David G. Andersen (May 14)
- Re: NTp sources that work in a datacenter (was Re: Is latency equivalent to RTT?) Rafi Sadowsky (May 14)