US operators are planning to shut down their CDMA networks. See for example https://www.fiercewireless.com/wireless/verizon-to-shut-down-2g-cdma-1x-network-by-end-2019
I wouldn't be surprised to see this date get pushed back though. On Mon, Jul 22, 2019 at 8:05 PM K5ROE Mike <[email protected]> wrote: > You may want to look at something an Endrun CDMA ntpserver for the > datacenter; don't need view of the sky. Available on the used market sub > $1k > > Standard solution for this scenario. > > > K5ROE Mike > > On 7/22/19 10:50 AM, wildylion via time-nuts wrote: > > Yeah, of course I will NOT do anything home-grown for the datacenter. > > > > But currently it uses 3 Stratum 2 NTP servers, one per DC, with them > referencing a list of 4 close-by Stratum 1 sources. > > > > ntpstat generally says that time is correct within ~50 ms, while jitter > and offset generally don't exceed 1ms, the root dispersion is quite large. > > Also these Stratum 2 NTPs are run from Cisco routers, which I doubt are > very good at timekeeping. > > > > When I implemented this scheme, I offered to have S2 on a set of x86 > servers, but was overruled by management who said it'll be better if we run > S2's off Cisco gear. > > > > So what if we add a couple GPSDO's into the mix, using them as primary > time sources alongside public Stratum1 NTP servers for sanity check? And of > course moving the S2's to something more stable. > > > > My own, homegrown S1 pool NTP is another matter entirely - I think just > a tuned Raspi with a M8N will be enough? > > > > Sent with [ProtonMail](https://protonmail.com) Secure Email. > > > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐ > > On Monday, 22 July 2019 г., 17:38, Taka Kamiya <[email protected]> > wrote: > > > >> If you have 100 production servers with database, I am going to > strongly discourage you from taking a "home grown" route. You will need > multiple redundant implementation with fail-over. You mentioned budget. > How much are your bosses willing to pay for consultation fees for failed or > corrupted data? I am assuming you are talking about Oracle RDBMS with > minimum of 2 way RAC. > >> > >> If you are using collocation services, doesn't the center itself offer > ntp service for fee? > >> > >> If you need 24 hour hold-over, I will take nothing less than multiple > ovenized crystal OSC GPSDO with redundancy per center. Then feed that into > ntp server with multi-location fail over. > >> > >> If I were responsible for managing such system and if my boss will want > me to go cheap route, I will seriously fight it. If it's successful, your > boss will get credit for spending little and getting a big benefit. WHEN > it fails, it's going to be your fault for not mitigating risk > sufficiently. Try pricing out 2 days of consulting fees.... > >> > >> --------------------------------------- > >> (Mr.) Taka Kamiya > >> KB4EMF / ex JF2DKG > >> > >> On Monday, July 22, 2019, 10:05:56 AM EDT, wildylion via time-nuts < > [email protected]> wrote: > >> > >> Hello there, > >> > >> I wanted to ask for advice regarding NTP > >> > >> Situation 1: > >> What I currently have is a uBlox M8N GPS puck I'm planning to use with > the Raspberry PI. Seems like it should work almost out of the box with some > kernel tuning, but I have a question about short term stability in the > event of GPS loss - how well will the board hold over if it's lost GPS for, > say, 24 hours? > >> > >> Situation 2: > >> Also, there's a need for more dependable NTP time sources for our > colocated spaces. > >> > >> What we have is about 100 servers, some of them running DBMS that > wouldn't like clock drift at all. After a recent incident involving NTP > I've got an idea to install GPSDO time servers in each datacenter and slave > them to stratum2's that will be actually distributing time to clients. > >> > >> All the certified GNSS disciplined clocks are really expensive (way > more than the management would approve), so what I'm planning to do is > possibly getting a couple LeoNTP units and using them as the root time > sources, would this be a good plan? Of course, all the NTP infrastructure > will be monitored, and possibly we'll use Stratum 2 servers which would be > slaved to GPSDO S1's AND the public NTP pool for sanity checks. > >> > >> Maybe BG7TBL's units instead of LeoNTP? > >> Is that a good idea? > >> > >> Sent with [ProtonMail](https://protonmail.com) Secure Email. > >> _______________________________________________ > >> time-nuts mailing list -- [email protected] > >> To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> and follow the instructions there. > > _______________________________________________ > > time-nuts mailing list -- [email protected] > > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
