nanog mailing list archives
Re: Time and Timing Servers
From: Måns Nilsson <mansaxel () besserwisser org>
Date: Fri, 12 Jul 2019 07:10:57 +0200
Subject: Re: Time and Timing Servers Date: Thu, Jul 11, 2019 at 10:23:41AM -0500 Quoting Mike Hammett (nanog () ics-il net):
I'll look into Meinberg.
Meinberg are nice people with good hardware. They can do 2048KHz from GPS and other timing signals, for instance. Then again, some router vendors do that in boxes you need anyway. As long as the controlling clock is PTP.
I recent thread mentioned high-sensitivity receivers often allow GPS to work inside. Obviously "inside" has a lot of definitions.
Indeed. Colo buildings rarely are on the forgiving side of "inside". In Sweden, most older central offices are built to some degree of bomb proofness (certainly not safe from direct hit) , with some 10mm of steel in shutters for all windows, etc. GPS fares not well there.
I will need this facility for the TDM timing signals. It's a central office, not a datacenter.
Then you're concerned with frequency and phase to ITU-T G.812, I suspect. Unless this is your "central central" office, in which case you need G.811.
I don't know that Internet-based NTP would be accurate enough for the timing signals that I need. Maybe, maybe not.
The current trend in today's large frequency/phase consumers, ie. mobile, is to run PTP over backhaul. Well behaved NTP _could_ make it, I suspect, given a good enough clock in the facility, but PTP will definitely work, assuming you have transmission and hardware capable of doing it. "Capable" here, means dark fibre or WDM is required together with routers and switches that can act as boundaries in PTP sense. If you rent MPLS or are using plain Internet infrastructure, it becomes a lot more complicated. There are frequency/phase transmission solutions (mostly broadcast related) that easily can transfer your central central cæsium clock frequency to another site using reasonable-quality IP transport, but those are neither cheap nor fire-and-forget. -- Måns Nilsson primary/secondary/besserwisser/machina MN-1334-RIPE SA0XLR +46 705 989668 I'm gliding over a NUCLEAR WASTE DUMP near ATLANTA, Georgia!!
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Current thread:
- Re: Time and Timing Servers, (continued)
- Re: Time and Timing Servers Brielle Bruns (Jul 15)
- Re: Time and Timing Servers Ryan Wilkins (Jul 11)
- Re: Time and Timing Servers Ethan O'Toole (Jul 11)
- Re: Time and Timing Servers Eric S. Raymond (Jul 11)
- Re: Time and Timing Servers Majdi S. Abbas (Jul 11)
- Re: Time and Timing Servers Mike Hammett (Jul 11)
- Re: Time and Timing Servers James R Cutler (Jul 11)
- Re: Time and Timing Servers Eric S. Raymond (Jul 11)
- Re: Time and Timing Servers Forrest Christian (List Account) (Jul 11)
- Re: Time and Timing Servers Jay R. Ashworth (Jul 15)
- Re: Time and Timing Servers Mike Hammett (Jul 11)
- Re: Time and Timing Servers Måns Nilsson (Jul 11)
- Re: Time and Timing Servers Mike Hammett (Jul 11)
- Re: Time and Timing Servers Måns Nilsson (Jul 11)
- Re: Time and Timing Servers Mike Hammett (Jul 11)