rfc1129.ps

RFC 的详细文档！

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450 2637 535 3 ( Discussion of Approaches)fjt
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450 2520 486 3 ( Network Time Protocol)fjt
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450 2404 414 3 ( Modes of Operation)fjt
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450 2171 373 2 ( Robustness Issues)fjt
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300 2113 38 0 (4.)fjt
450 2113 903 5 ( Sample Processing and Selection Operations)fjt
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300 2054 75 0 (4.1.)fjt
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450 1996 298 2 ( Peer Selection)fjt
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2200 1996 50 0 (16)fjt
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450 1938 411 3 ( Local Clock Design)fjt
863 1938 1313 35 ( . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .)fjt
2200 1938 50 0 (18)fjt
300 1880 38 0 (6.)fjt
450 1880 557 5 ( NTP in the Internet System)fjt
1013 1880 1163 31 ( . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .)fjt
2200 1880 50 0 (21)fjt
300 1821 75 0 (6.1.)fjt
450 1821 279 2 ( Time Servers)fjt
750 1821 1425 38 ( . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .)fjt
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300 1763 75 0 (6.2.)fjt
450 1763 490 2 ( Synchronization Subnet)fjt
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300 1647 38 0 (7.)fjt
450 1647 362 2 ( Future Directions)fjt
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1104 1501 343 2 (List of Figures)fjt
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300 1413 650 3 (Figure 1. Implementation Model)fjt
975 1413 1238 33 ( . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .)fjt
2225 1413 25 0 (6)fjt
300 1355 588 4 (Figure 2. NTP Packet Header)fjt
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300 1297 774 5 (Figure 3. Calculating Delay and Offset)fjt
1088 1297 1088 29 ( . . . . . . . . . . . . . . . . . . . . . . . . . . . . .)fjt
2200 1297 50 0 (11)fjt
300 1239 505 4 (Figure 4. Offset vs Delay)fjt
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2200 1239 50 0 (14)fjt
300 1180 688 4 (Figure 5. Phase-Lock Loop Model)fjt
1013 1180 1163 31 ( . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .)fjt
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300 1122 440 3 (Figure 6. Raw Offsets)fjt
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300 1064 503 3 (Figure 7. Filtered Offsets)fjt
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2200 1064 50 0 (23)fjt
300 1006 551 3 (Figure 8. Error Distribution)fjt
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1115 918 321 2 (List of Tables)fjt
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300 831 740 4 (Table 1. Outlyer Selection Procedure)fjt
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300 2979 227 1 (RFC 1129)fjt
938 2979 676 2 (Network Time Synchronization)fjt
1949 2979 302 1 (October 1989)fjt
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300 2746 1950 16 (How do hosts and gateways in a large, dispersed networking community know what time it is? How)fjt
300 2688 1914 15 (accurate are their clocks? In a recent survey involving 94,260 hosts and gateways of the Intern)fjt
2214 2688 36 0 (et)fjt
300 2629 1950 13 (system [MIL89b], 20,758 provided local time using three time-transfer protocols. About half of the)fjt
300 2571 1890 15 (replies had errors greater than two minutes, while ten percent had errors greater than four hours)fjt
2190 2571 61 1 (. A)fjt
300 2513 1950 15 (few had errors over two weeks. Most local clocks are set by eyeball-and-wristwatch to within a)fjt
300 2455 1950 16 (minute or two and rarely checked after that. Many of these are maintained by some sort of)fjt
300 2396 1882 10 (battery-backed clock/calender device using a room-temperature crystal oscillator that may drif)fjt
2182 2396 68 1 (t as)fjt
300 2338 1938 16 (much as a second per day and can go for weeks between manual corrections. For many applications)fjt
2238 2338 13 0 (,)fjt
300 2280 1752 10 (especially distributed internet applications, much greater accuracy and reliability is requ)fjt
2052 2280 90 0 (ired.)fjt
300 2177 1827 13 (Accurate, reliable time is necessary for financial and legal transactions, stocks and bonds tr)fjt
2127 2177 123 0 (ading,)fjt
300 2119 1864 10 (transportation reservation, dispatch and control, and many other applications involving wi)fjt
2164 2119 86 0 (dely)fjt
300 2061 1832 9 (distributed resources. These applications often require multiple, concurrent, real-time acc)fjt
2132 2061 118 1 (ess to)fjt
300 2002 1826 12 (databases distributed over an internet of many networks. Internet time synchronization is nec)fjt
2126 2002 124 0 (essary)fjt
300 1944 1835 11 (for reliable caching, archiving and transaction sequencing. Even the management functions )fjt
2135 1944 115 1 (of the)fjt
300 1886 1938 13 (internet and its component networks need accurate time in order to manage control activation)fjt
2238 1886 13 0 (,)fjt
300 1828 1834 10 (monitoring coordination and significant event timestamping. Coordinated network time is ext)fjt
2134 1828 99 0 (reme)fjt
2234 1828 17 0 (-)fjt
300 1769 1626 11 (ly useful when searching for elusive bugs and transients in day-to-day operations.)fjt
300 1667 1889 14 (This paper presents an overview of the architecture, protocol and algorithms of the Network Ti)fjt
2189 1667 61 0 (me)fjt
300 1609 1874 13 (Protocol \(NTP\) used in the Internet system to synchronize clocks and coordinate time distribut)fjt
2174 1609 76 0 (ion.)fjt
300 1550 1845 12 (The Internet consists of over 100,000 hosts on about 800 packet-switching networks interconn)fjt
2145 1550 105 0 (ected)fjt
300 1492 1189 11 (by a similar number of gateways. In this paper the capitalized )fjt
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1489 1492 157 0 (Internet)fjt
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1646 1492 604 5 ( refers to this particular system,)fjt
300 1434 479 3 (while the uncapitalized )fjt
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779 1434 155 0 (internet)fjt
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934 1434 1317 9 ( refers to any generic system of multiple networks interconnected)fjt
300 1376 1916 13 (by gateways. While the backbone networks and gateways are carefully engineered for good servic)fjt
2216 1376 35 0 (e,)fjt
300 1317 1774 11 (operating speeds and service reliability vary considerably throughout the Internet. This plac)fjt
2074 1317 176 1 (es severe)fjt
300 1259 1950 14 (demands on NTP, which must deliver accurate and reliable time in spite of component failures,)fjt
300 1201 1313 5 (service disruptions and possibly mis-engineered implementations.)fjt
300 1098 1950 13 (In the remainder of this introductory Section 1, issues in the requirements, approaches and)fjt
300 1040 1902 12 (comparisons with previous work are discussed. The architecture of the NTP synchronization subn)fjt
2202 1040 48 0 (et,)fjt
300 982 1875 12 (including the primary time references and distribution mechanisms, is described in Section 2.)fjt
2175 982 75 1 ( An)fjt
300 923 1851 16 (overview of the NTP protocol is given in Section 3 and further intricacies in a formal specific)fjt
2151 923 100 0 (ation)fjt
300 865 1884 11 (and implementation guide published elsewhere [MIL89a]. Section 4 describes the algorithms u)fjt
2184 865 66 0 (sed)fjt
300 807 1873 13 (to improve the accuracy of delay and offset measurements made over statistically noisy inte)fjt
2173 807 77 0 (rnet)fjt
300 749 1854 17 (paths and to select the best clock from among a set of mutually suspicious clocks. Section 5 desc)fjt
2154 749 97 0 (ribes)fjt
300 690 1950 13 (a local clock design based on a first-order, adaptive-parameter phase-lock loop and capable of)fjt
300 632 1870 14 (accuracies to the order of a millisecond, even after extended periods when all synchronization p)fjt
2170 632 80 0 (aths)fjt
300 574 1834 12 (to primary reference sources have been lost. The international NTP synchronization subnet o)fjt
2134 574 116 1 (f time)fjt
300 516 1768 14 (servers and clients now operating on the Internet is described and its performance assessed i)fjt
2068 516 182 1 (n Section)fjt
300 457 1950 15 (6. Further details on measured performance in the Internet can be found in [MIL89b]. Section 7)fjt
300 399 1210 7 (discusses further development and issues for future research.)fjt
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300 2979 227 1 (RFC 1129)fjt
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