We use an older model of https://www.microsemi.com/product-directory/enterprise-network-time-servers/4117-syncserver-s600 with rubidium oscillator. Not cheap, but hardened and extremely accurate.

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Matthew Huff             | 1 Manhattanville Rd

Director of Operations   | Purchase, NY 10577

OTA Management LLC       | Phone: 914-460-4039

From: Shawn L [mailto:shawnl@up.net]
Sent: Sunday, December 30, 2018 9:40 AM
To: nanog@nanog.org
Cc: Matthew Huff <mhuff@ox.com>; list@satchell.net
Subject: Re: CenturyLink

Speaking of GPS-enabled NTP appliances, etc. wondering what hardware people are using for this.

thanks

-----Original Message-----
From: "Raymond Burkholder" <ray@oneunified.net>
Sent: Saturday, December 29, 2018 12:01pm
To: "Matthew Huff" <mhuff@ox.com>, "list@satchell.net" <list@satchell.net>, "nanog@nanog.org" <nanog@nanog.org>
Subject: Re: CenturyLink

On 2018-12-29 7:51 a.m., Matthew Huff wrote:
> We have two stratum-1 servers synced with GPS and a PTP feed from a provider that also provides PTP to market data systems, but we still have to monitor drift between system time and NIST time. Don't ask for the logic behind it, it's a regulation, not a technical requirement.
>
On one occasion, due to bad firmware or a configuration issue, I have
seen GPS stratum 1 diverge from NTP.  It was somewhat eye brow raising
to the company.  My NTP monitored servers were shown to be diverging
their GPS/NTP, but after looking at twice or thrice, it was the other
way around.