1 Notes for NTP Version 3 2 3 This version operates in much the same manner as Version 2 with the 4 following changes and additions: 5 6 1. The protocol machinery operates in conformance with the RFC1305 NTP 7 Version 3 specification. The most visible characteristic of this 8 version is that the poll intervals for all polls, even selected 9 ones, is significantly increased. This is especially desirable when 10 serving a large client population. This implementation supports 11 previous versions as non-configured peers; for version-2 configured 12 peers a "version 2" keyword should be included on the "peer" line. 13 14 2. The configuration file has a new keyword: statfile <file>, where 15 <file> is the name of a statistics file." When present, each clock 16 update generates an entry of the form: 17 18 <day> <sec>.<frac> <addr> <status> <offset> <delay> <disp> 19 20 where <day> is the modified Julian day, <sec>.<frac> is the time of 21 day, <addr> is the peer address and <status> is the peer status. 22 The <offset>, <delay> and <disp> are the measured offset, delay and 23 dispersion, respectively, of the peer clock relative to the local 24 clock. About once per day the current file is closed and a new one 25 created with names <file>.<gen>, where <gen> starts at one and 26 increments for each new generation. 27 28 3. A number of additional platforms are supported. See ./Config file 29 for details. 30 31 4. A driver for the TrueTime 468DC GOES Synchronized Clock is 32 included. This driver (refclock_goes.c) should also work for other 33 TrueTime radio clocks, since all use the same format. 34 35 5. A replacement driver for the Spectracom 8170 WWVB Synchronized 36 Clock is included. This driver (refclock_wwvb.c) (a) does not 37 require a 1-pulse-per-second signal, (b) supports both format 0 38 (original 8170) and format 2 (Netclock/2 and upgraded 8170), (c) 39 can be connected to more than one computer and (d) automatically 40 compensates for all serial baud rates. 41 42 6. A driver for the German time/frequency station DCF77 is included. 43 This requires a special STREAMS module. 44 45 7. In Version 2 special line-discipline modules were required for the 46 CHU and WWVB drivers. This code continues to work in Version 3, 47 although it is no longer needed for the WWVB driver. However, this 48 code does not work under STREAMS, as used in SunOS 4.1.1. 49 Equivalent STREAMS modules are supplied with Version 3. 50 51 8. Support for an external 1-pulse-per-second (pps) signal is 52 provided. The signal is connected to a serial port (see 53 xntpd/ntp_loopfilter.c for details). When present the leading edge 54 of the pulse establishes the on-time epoch within an interval 55 established by the selected radio clock or other NTP time server. 56 Use of the pps is indicated when the tattletale displayed by ntpq 57 changes from "*" to "o". 58 59 9. The clock-selection and poll-update procedures have been modified 60 slightly in order to achieve better performance on high speed LANs 61 with compromise in performance on typical WANs. 62 63 10. In order to comply with U.S. Commerce Department regulations, the DES 64 encryption routine lib/authdes.c cannot be exported. For exportable 65 versions of this distribution a DES-encrypted version of this routine 66 lib/authdes.c.des is included along with an unencrypted version 67 lib/authdes.c.export, which allows normal operation, but without the 68 NTP authentication feature. Further information is available in the 69 lib/authdes.c.export file. 70 71 11. As an alternative to the DES-based authentication mechanism, an 72 implementation of the RSA Message Digest 5 algorithm is provided. 73 (see applicable copyright information in the library files). 74 75 12. A driver for the Magnavox MX4200 GPS clock. 76 77 13. A STREAMS module which captures carrier-detect data-lead transitions to 78 connect a precision source of 1-pps, yet avoid the ugly overhead in the 79 usual STREAMS processing. See the ppsclock subdirectory. 80 81 14. Support for the Apple A/UX operating system and enhanced support for the 82 Hewlet-Packard HP/UX operating system. See the various README and Config 83 files for further information. 84 85 See the COPYRIGHT file for authors and copyright information. Note that some 86 modules in this distribution contain copyright information that supersedes 87 the copyright information in that file. 88 89 If I missed something or neglected to give due credit, please advise. 90 91 David L. Mills 92 University of Delaware 93 31 May 1992, amended 23 July 1992, 25 October 1992 94 95 Bugs and notes 96 97 A bug in the original tty_clk_STREAMS.c module has been fixed. 98 99 The poll-interval randomization feature of poll_update (in 100 xntpd/ntp_proto.c) has been extended to apply when the poll interval is 101 increased, as well as reduced. This spreads the update messages in time 102 and helps avoid unpleasant bursts of messages. 103 104 In the clock_select algorithm the peers selected for combining are 105 limited to those survivors at the lowest stratum, not the entire list. 106 This helps avoid whiplash when large numbers of peers are at the same 107 stratum. 108 109 The number formerly displayed by ntpq as "compliance" is now the time 110 constant of integration. 111 112 The DNS resolver xntpd/ntp_intres.c is now integrated into xntpd, making 113 configuration of multiple hosts easier. 114 115 System and peer event are now written to the system log at priority 116 LOG_INFO. 117 118 The leap-second code was fixed to avoid broadcasting leap warnings on 119 all except the last day of June and December. 120
Indexes created Mon Aug 24 00:24:59 UTC 2026