📄 rfc956.txt
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In the following table "Host" is the canonical name of the host and "Count" the number of replies received. The remaining data represent the time offset, in seconds, necessary to correct the local (reference) clock to agree with the host cited. The "Max" and "Min" represent the maximum and minimum of these offsets, while "Mean" represents the mean value and "Var" the variance, all rounded to the nearest second. Host Count Max Min Mean Var ----------------------------------------------------------- BBN-CLXX.ARPA 4 -11 -12 -11 0 BBN-KIWI.ARPA 4 -11 -12 -11 0 BBN-META.ARPA 4 -11 -12 -11 0 BBNA.ARPA 1 22 22 22 0 BBNG.ARPA 4 87 87 87 0 BELLCORE-CS-GW.ARPA 3 72 71 71 0 BLAYS.PURDUE.EDU 2 -1 -1 -1 0 CMU-CC-TE.ARPA 4 -94 -95 -94 0 CMU-CS-C.ARPA 3 6 5 5 0 CMU-CS-CAD.ARPA 4 -37 -37 -37 0 CMU-CS-CFS.ARPA 3 -42 -43 -42 0 CMU-CS-G.ARPA 3 -30 -31 -30 0 CMU-CS-GANDALF.ARPA 3 -42 -43 -42 0 CMU-CS-H.ARPA 4 -36 -37 -36 0 CMU-CS-IUS.ARPA 3 -44 -45 -44 0 CMU-CS-IUS2.ARPA 3 -44 -44 -44 0 CMU-CS-K.ARPA 3 -31 -31 -31 0 CMU-CS-SAM.ARPA 4 -74 -75 -74 0 CMU-CS-SPEECH.ARPA 4 -39 -40 -39 0 CMU-CS-SPEECH2.ARPA 4 -49 -50 -49 0 CMU-CS-SPICE.ARPA 4 -131 -132 -131 0 CMU-CS-THEORY.ARPA 4 -36 -37 -36 0 CMU-CS-UNH.ARPA 4 -44 -45 -44 0 CMU-CS-VLSI.ARPA 4 -66 -66 -66 0 CMU-RI-ARM.ARPA 3 -41 -41 -41 0 CMU-RI-CIVE.ARPA 3 -44 -45 -44 0 CMU-RI-FAS.ARPA 4 -27 -28 -27 0 CMU-RI-ISL1.ARPA 4 -18 -19 -18 0 CMU-RI-ISL3.ARPA 3 -49 -50 -49 0 CMU-RI-LEG.ARPA 3 -33 -33 -33 0 CMU-RI-ML.ARPA 4 42 42 42 0 CMU-RI-ROVER.ARPA 4 -48 -49 -48 0 CMU-RI-SENSOR.ARPA 2 -40 -41 -40 0 CMU-RI-VI.ARPA 3 -65 -65 -65 0 COLUMBIA.ARPA 1 8 8 8 0 CU-ARPA.CS.CORNELL.EDU 4 5 3 4 0 CYPRESS.ARPA 4 2 1 1 0Mills [Page 16] RFC 956 September 1985Algorithms for Synchronizing Network Clocks DCN1.ARPA 4 0 0 0 0 DCN5.ARPA 4 0 0 0 0 DCN6.ARPA 4 0 0 0 0 DCN7.ARPA 4 -1 -1 0 0 DCN9.ARPA 4 -3 -3 -3 0 DEVVAX.TN.CORNELL.EDU 2 3659 3658 3658 0 ENEEVAX.ARPA 4 73 72 72 0 FORD-WDL1.ARPA 4 -59 -60 -59 0 FORD1.ARPA 4 0 0 0 0 GUENEVERE.PURDUE.EDU 3 1 0 0 0 GVAX.CS.CORNELL.EDU 4 -18 -18 -18 0 IM4U.ARPA 4 -6 -6 -6 0 IPTO-FAX.ARPA 4 0 0 0 0 KANKIN.ARPA 4 -3 -4 -3 0 MERLIN.PURDUE.EDU 2 3 3 3 0 MIT-ACHILLES.ARPA 4 16 16 16 0 MIT-AGAMEMNON.ARPA 4 -63 -64 -63 0 MIT-ANDROMACHE.ARPA 4 -28 -28 -28 0 MIT-APHRODITE.ARPA 4 -7 -8 -7 0 MIT-APOLLO.ARPA 4 -8 -9 -8 0 MIT-ARES.ARPA 4 -25 -26 -25 0 MIT-ARTEMIS.ARPA 4 -34 -35 -34 0 MIT-ATHENA.ARPA 4 -37 -37 -37 0 MIT-ATLAS.ARPA 4 -26 -26 -26 0 MIT-CASTOR.ARPA 4 -35 -35 -35 0 MIT-DAFFY-DUCK.ARPA 2 -72 -73 -72 0 MIT-DEMETER.ARPA 4 -28 -29 -28 0 MIT-GOLDILOCKS.ARPA 1 -20 -20 -20 0 MIT-HECTOR.ARPA 4 -23 -24 -23 0 MIT-HELEN.ARPA 4 6 5 5 0 MIT-HERA.ARPA 4 -34 -35 -34 0 MIT-HERACLES.ARPA 4 -36 -36 -36 0 MIT-JASON.ARPA 4 -36 -37 -36 0 MIT-MENELAUS.ARPA 4 -32 -33 -32 0 MIT-MULTICS.ARPA 3 25 23 24 0 MIT-ODYSSEUS.ARPA 4 20 19 19 0 MIT-ORPHEUS.ARPA 4 -34 -35 -34 0 MIT-PARIS.ARPA 4 -35 -35 -35 0 MIT-POSEIDON.ARPA 4 -39 -41 -40 0 MIT-PRIAM.ARPA 4 -24 -25 -24 0 MIT-REAGAN.ARPA 4 115 115 115 0 MIT-THESEUS.ARPA 4 -43 -44 -43 0 MIT-TRILLIAN.ARPA 4 -38 -39 -38 0 MIT-TWEETY-PIE.ARPA 3 106 105 105 0 MIT-ZERMATT.ARPA 4 -75 -76 -75 0 MIT-ZEUS.ARPA 4 -37 -39 -38 0 MOL.ARPA 2 -3 -3 -3 0Mills [Page 17] RFC 956 September 1985Algorithms for Synchronizing Network Clocks MUNGO.THINK.COM 4 -1 -1 -1 0 NETWOLF.ARPA 4 158 157 157 0 ORBIT.ARPA 3 -4 -5 -4 0 OSLO-VAX.ARPA 3 3729 3727 3728 1 PATCH.ARPA 1 18 18 18 0 RADC-MULTICS.ARPA 4 -14 -15 -14 0 RICE-ZETA.ARPA 1 -31 -31 -31 0 RICE.ARPA 1 7 7 7 0 ROCHESTER.ARPA 4 -18 -18 -18 0 ROCK.THINK.COM 4 2 2 2 0 SCRC-QUABBIN.ARPA 4 -100 -100 -100 0 SCRC-RIVERSIDE.ARPA 4 -128 -128 -128 0 SCRC-STONY-BROOK.ARPA 4 -100 -100 -100 0 SCRC-VALLECITO.ARPA 4 -57 -57 -57 0 SCRC-YUKON.ARPA 4 -65 -65 -65 0 SEBASTIAN.THINK.COM 4 -14 -15 -14 0 SEISMO.CSS.GOV 3 -1 -1 0 0 SRI-BISHOP.ARPA 4 -40 -41 -40 0 SRI-DARWIN.ARPA 2 -29 -30 -29 0 SRI-HUXLEY.ARPA 2 -28 -29 -28 0 SRI-KIOWA.ARPA 4 -29 -30 -29 0 SRI-LASSEN.ARPA 3 -11 -12 -11 0 SRI-MENDEL.ARPA 4 74 73 73 0 SRI-PINCUSHION.ARPA 4 -50 -51 -50 0 SRI-RITTER.ARPA 4 -23 -24 -23 0 SRI-TIOGA.ARPA 4 127 127 127 0 SRI-UNICORN.ARPA 4 -38486 -38486 -38486 0 SRI-WHITNEY.ARPA 4 -24 -24 -24 0 SRI-YOSEMITE.ARPA 4 -26 -27 -26 0 SU-AIMVAX.ARPA 2 -54 -55 -54 0 SU-COYOTE.ARPA 1 14 14 14 0 SU-CSLI.ARPA 4 -1 -1 -1 0 SU-PSYCH.ARPA 1 -52 -52 -52 0 SU-SAFE.ARPA 1 -60 -60 -60 0 SU-SIERRA.ARPA 4 -53 -53 -53 0 SU-SUSHI.ARPA 4 -105 -106 -105 0 SU-WHITNEY.ARPA 2 -14 -14 -14 0 TESLA.EE.CORNELL.EDU 3 -2 -3 -2 0 THORLAC.THINK.COM 4 -20 -20 -20 0 TRANTOR.ARPA 4 4 3 3 0 TZEC.ARPA 4 -6 -7 -6 0 UBALDO.THINK.COM 4 -13 -13 -13 0 UCI-CIP.ARPA 2 -566 -567 -566 0 UCI-CIP2.ARPA 2 -175 -175 -175 0 UCI-CIP3.ARPA 2 -89 -90 -89 0 UCI-CIP4.ARPA 2 -51 -51 -51 0 UCI-CIP5.ARPA 2 -26 -28 -27 1Mills [Page 18] RFC 956 September 1985Algorithms for Synchronizing Network Clocks UCI-ICSA.ARPA 2 -24 -24 -24 0 UCI-ICSC.ARPA 1 0 0 0 0 UCI-ICSD.ARPA 1 -24 -24 -24 0 UCI-ICSE.ARPA 1 -10 -10 -10 0 UDEL-DEWEY.ARPA 1 88 88 88 0 UDEL-MICRO.ARPA 2 64 64 64 0 UIUC.ARPA 4 105 103 104 0 UIUCDCSB.ARPA 4 65 65 65 0 UMD1.ARPA 4 0 0 0 0 UMICH1.ARPA 4 -1 -1 0 0 UO.ARPA 4 -2 -3 -2 0 USC-ISI.ARPA 4 -45 -45 -45 0 USC-ISIC.ARPA 4 28 26 27 0 USC-ISID.ARPA 4 26 25 25 0 USC-ISIE.ARPA 4 -53 -54 -53 0 USC-ISIF.ARPA 4 -29 -29 -29 0 USGS2-MULTICS.ARPA 3 75 74 74 0 UT-ALAMO.ARPA 4 22 22 22 0 UT-BARKLEY.ARPA 4 57 56 56 0 UT-EMIL.ARPA 4 29 28 28 0 UT-GOTTLOB.ARPA 4 42 41 41 0 UT-HASKELL.ARPA 4 6 6 6 0 UT-JACQUES.ARPA 4 21 20 20 0 UT-SALLY.ARPA 3 1 0 0 0 VALENTINE.THINK.COM 4 -10 -11 -10 0 WENCESLAS.THINK.COM 4 -2 -3 -2 0 XAVIER.THINK.COM 4 -14 -14 -14 0 XEROX.ARPA 4 0 0 0 0 YAXKIN.ARPA 3 -4 -5 -4 0 YON.THINK.COM 4 -11 -12 -11 0 ZAPHOD.PURDUE.EDU 4 -230 -231 -230 0 ZOTZ.ARPA 4 17 16 16 0 Table A1. UDP Host Clock Offsets for Various Internet Hosts The above list includes several host clocks known to be synchronized to various radio clocks, including DCN1.ARPA (WWVB), DCN6.ARPA (WWV) and FORD1.ARPA (GOES). Under normal radio receiving conditions these hosts should be accurate to well within a second relative to NBS standard time. Certain other host clocks are synchronized to one of these hosts using protocols described in RFC-891, including DCN5.ARPA, DCN7.ARPA and UMD1.ARPA (synchronized to DCN1.ARPA) and UMICH1.ARPA (synchronized to FORD1.ARPA). It is highly likely, but not confirmed, that several other hosts with low offsets derive local time from one of these hosts or from other radio clocks.Mills [Page 19] RFC 956 September 1985Algorithms for Synchronizing Network Clocks The raw statistics computed from the weighted data indicate a mean of -261 sec, together with a maximum of 3729 sec and a minimum of -38486 sec. Obviously, setting a local clock on the basis of these statistics alone would result in a gross error. A closer look at the distribution of the data reveals some interesting features. Table A2 is a histogram showing the distribution within a few seconds of reference time. In this and following tables, "Offset" is in seconds and indicates the lower-valued corner of the histogram bin, which extends to the next higher value, while "Count" indicates the number of samples falling in that bin. Offset Count Offset Count ------------- ------------- 0 sec 13 (continued) 1 1 -1 3 2 1 -2 3 3 2 -3 3 4 1 -4 2 5 2 -5 0 6 1 -6 2 7 1 -7 1 8 1 -8 1 9 0 -9 0 > 9 30 < -9 95 Table A2. Offset Distribution < 9 sec A total of 16 of the 163 host clocks are within a second in accuracy, while a total of 125 are off more than ten seconds. It is considered highly likely that most of the 16 host clocks within a second in offset are synchronized directly or indirectly to a radio clock. Table A3 is a histogram showing the distribution over a larger scale.Mills [Page 20] RFC 956 September 1985Algorithms for Synchronizing Network Clocks⌨️ 快捷键说明
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