[ntp:questions] Re: wireless routers beating on NTP servers

Wolfgang S. Rupprecht wolfgang+gnus20040120T090554 at dailyplanet.dontspam.wsrcc.com
Tue Jan 20 17:26:25 UTC 2004


jcs at no_s_p_a_m.zoo.bt.co.uk (John Sager) writes:
> In article <x7fzed3oe3.fsf at capsicum.wsrcc.com>,
> 	"Wolfgang S. Rupprecht"          <wolfgang+gnus20040117T190822 at dailyplanet.dontspam.wsrcc.com> writes:
>> 
>> Lets home the critical infrastructure can be convinced to buy their
>> own GPS based stratum-1's to supplement external time sources.
>
> Excuse me if I laugh, Wolfgang. The recent PRN23 fault (you wouldn't
> have seen it in SF) showed up some shortcomings in GPS time sources.
> I suspect it didn't have too big an impact on NTP clocks, but
> a lot of our GPS-referenced backup network frequency sources dropped
> off line for an hour or two.

Finally something exciting happens with the GPS constellation and I
entirely miss it?  Sheesh!  (I see I'm going to have to google to see
what I missed.)  I do have full second-by-second lat/lon/elev/time
logs covering the last 2 months so if it effected me or anyone my ntpd
talked to I should be able to spot it.  The map at Shriever seems to
indicates the SV had the good graces to fail when it was over Asia and
not visible from the Lower-48 US states.

http://www.schriever.af.mil/GpsSupportCenter/archive/Frontpage/SVN23_Figure1.jpg
http://www.schriever.af.mil/GpsSupportCenter/

I did think a bit about which mode to run my gps in and I use normal
"3-D" (really 4-D) mode.  I would hope that that mode is more tested
than the timing mode.  Perhaps the code to remove the outliers would
have worked???  Was there a any resolution in terms of which
units/firmware did the right thing?

-wolfgang
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