[ntp:questions] refid 'STC ' ? What does "STC" signify?

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Thu Jan 22 15:37:08 UTC 2009


On Jan 22, 8:57 am, Martin Burnicki <martin.burni... at meinberg.de>
wrote:
> Steve,
>
>
>
> Steve Kostecke wrote:
> > Here is the list I assembled from the current driver pages:
>
> > Driver Name                                               Ref-Id
> > ------ --------------------------------------------------
> > --------------------
> > 1      Undisciplined Local Clock                          LCL
> > 2      Trak 8820 GPS Receiver                             GPS
> > 3      PSTI/Traconex 1020 WWV/WWVH Receiver               WWV
> > 4       WWVB/GPS Receivers                                WWVB
> > 5      TrueTime GPS/GOES/OMEGA Receivers                  GPS, OMEGA, GOES
> > 6      IRIG Audio Decoder                                 IRIG
> > 7      Radio CHU Audio Demodulator/Decoder                CHU
> > 8      Generic Reference Driver                           PARSE
> > 9      Magnavox MX4200 GPS Receiver                       GPS
> > 10     Austron 2200A/2201A GPS Receivers                  GPS
> > 11     Arbiter 1088A/B GPS Receiver                       GPS
> > 12     KSI/Odetics TPRO/S IRIG Interface                  IRIG
> > 16     Bancomm bc635VME Time and Frequency Processor      BTFP
> > 18     NIST/USNO/PTB Modem Time Services                  NIST
> > 19     Heath WWV/WWVH Receiver                            WWV
> > 20     Generic NMEA GPS Receiver                          GPS
> > 22     PPS Clock Discipline                               PPS
> > 26     Hewlett Packard 58503A GPS Receiver and HP Z3801A  GPS
> > 27     Arcron MSF Receiver                                MSFa, MSF, DCF,
> > WWVB
> > 28     Shared memoy Driver                                SHM
> > 29     Trimble Palisade and Thunderbolt Receivers         GPS
> > 31     Rockwell Jupiter GPS Receiver                      GPS
> > 32     Chrono-log K-series WWVB receiver                  CHRONOLOG
> > 33     Dumb Clock                                         DUMBCLOCK
> > 34     Ultralink Clock                                    WWVB
> > 35     Conrad parallel port radio clock                   PCF
> > 36     Radio WWV/H Audio Demodulator/Decoder              WVf or WHf
> > 37     Forum Graphic GPS Dating station                   GPS
> > 38     hopf clock drivers by ATLSoft                      HOPF (default),
> >                                                           GPS, DCF
> > 39     hopf clock drivers by ATLSoft                      HOPF (default),
> >                                                           GPS, DCF
> > 40     JJY Receivers                                      JJY
> > 42     Zyfer GPStarplus Receiver                          GPS
> > 43     RIPE NCC interface for Trimble Palisade            RIPENCC
> > 44     NeoClock4X                                         NEOL
>
> > As has been mentioned elsewhere in this thread, the Reference ID may be
> > set in ntp.conf.
>
> AFAIK the refid (as reported in the ntpq -p billboard) can only have up to 4
> characters since it's transported in a 32 bit value in the NTP packet, so
> it's not possible to set it e.g. to "OMEGA" or "DUMBCLOCK".
>
> Also, e.g. the parse driver sets the default refid for a refclock depending
> on the mode, e.g. "DCFp", "DCFa", or "GPS".
>
> And yes, the refid of a refclock can be set in ntp.conf, e.g.:
>
> server 172.127.8.0 mode 2    # sets the refid to "DCFa"
> fudge 172.127.8.0 refid STC  # changes the refid to "STC"  ;-)
>
> Martin
> --
> Martin Burnicki
>
> Meinberg Funkuhren
> Bad Pyrmont
> Germany

So other than using ntptrace to see if the refclock is reported as an
upstream server (an unlikely stratum 0) or something else, there's
really no way to know what the heck it  is in reality. I can't say
that idea gives me a warm, fuzzy feeling. Correct me if I'm wrong, but
my non-caffeinated brain is telling me someone driven by a budget
could set up a server using nothing but it's LCL clock as a source but
fudge the ID to be something else. On an isolated network, there'd be
no way to detect this (assuming for this academic argument you don't
wear a reasonably accurate watch). I can imagine a group of such
servers peering with each other endlessly hunting around themselves.

If ntpd came with a "fixStupidNtpConf.ss" script, I'd feel better
about this.

Phreon




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