Regulatory. If we were to lose the GPS signal (antenna failure, etc...) then our stratum 1 time sources wouldn't drift as much and as quickly. For telco and general usage, the cost may not be worthwhile, but when you have auditors looking over your shoulder.... ---- Matthew Huff | 1 Manhattanville Rd Director of Operations | Purchase, NY 10577 OTA Management LLC | Phone: 914-460-4039 -----Original Message----- From: Saku Ytti [mailto:saku@ytti.fi] Sent: Sunday, December 30, 2018 12:30 PM To: Matthew Huff <mhuff@ox.com> Cc: Shawn L <shawnl@up.net>; nanog@nanog.org Subject: Re: CenturyLink Hey Matthew,
We use an older model of https://www.microsemi.com/product-directory/enterprise-network-time-servers/... with rubidium oscillator. Not cheap, but hardened and extremely accurate.
Out of interest why rubidium? For short term stability oscillator choice isn't much of a matter for free running even rubidium will be off good +-1us per day or +-30us per week. I've always wondered what niche rubidium covers that isn't handled by much cheaper crystal ovens or actually precise oscillators. -- ++ytti