rfc1119.ps

著名的RFC文档,其中有一些文档是已经翻译成中文的的.

300 872 1870 15 (a variant of the returnable-time system used in some digital telephone networks [6]. The clock f)fjt
2170 872 80 0 (ilter)fjt
300 814 1873 12 (and selection algorithms are designed so that the clock synchronization subnet self-organizes )fjt
2173 814 78 0 (into)fjt
300 755 1950 12 (a hierarchical-master-slave configuration [8]. What makes the NTP model unique is the adaptive)fjt
300 697 1805 12 (configuration, polling, filtering and selection functions which tailor the dynamics of the sy)fjt
2105 697 145 1 (stem to)fjt
300 639 784 4 (fit the ubiquitous Internet environment.)fjt
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300 547 42 0 (2.)fjt
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300 457 1889 15 (The purpose of NTP is to connect a number of primary reference sources, synchronized to natio)fjt
2189 457 61 0 (nal)fjt
300 399 1950 13 (standards by wire or radio, to widely accessible resources such as backbone gateways. These)fjt
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300 2979 230 0 (RFC-1119)fjt
1024 2979 504 2 (Network Time Protocol)fjt
1882 2979 369 1 (September 1989)fjt
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300 2014 1950 14 (gateways, acting as primary time servers, use NTP between them to cross-check the clocks and)fjt
300 1956 1950 13 (mitigate errors due to equipment or propagation failures. Some number of local-net hosts or)fjt
300 1898 1950 16 (gateways, acting as secondary time servers, run NTP with one or more of the primary servers. In)fjt
300 1840 1848 15 (order to reduce the protocol overhead, the secondary servers distribute time via NTP to the rema)fjt
2148 1840 103 0 (ining)fjt
300 1781 1850 14 (local-net hosts. In the interest of reliability, selected hosts can be equipped with less accurat)fjt
2150 1781 100 1 (e but)fjt
300 1723 1909 16 (less expensive radio clocks and used for backup in case of failure of the primary and/or seconda)fjt
2209 1723 42 0 (ry)fjt
300 1665 937 5 (servers or communication paths between them.)fjt
300 1571 1931 14 (There is no provision for peer discovery or virtual-circuit management in NTP. Data integrity i)fjt
2231 1571 19 0 (s)fjt
300 1513 1934 11 (provided by the IP and UDP checksums. No circuit-management, duplicate-detection or retransmis)fjt
2234 1513 17 0 (-)fjt
300 1454 1950 15 (sion facilities are provided or necessary. The service can operate in a symmetric mode, in which)fjt
300 1396 1826 12 (servers and clients are indistinguishable, yet maintain a small amount of state information)fjt
2126 1396 124 2 (, or in)fjt
300 1338 1889 15 (client/server mode, in which servers need maintain no state other than that contained in the cli)fjt
2189 1338 61 0 (ent)fjt
300 1280 1950 8 (request. A lightweight association-management capability, including dynamic reachability and)fjt
300 1221 1950 12 (variable polling-rate mechanisms, is included only to manage the state information and reduce)fjt
300 1163 1950 14 (resource requirements. Since only a single NTP message format is used, the protocol is easily)fjt
300 1105 1769 13 (implemented and can be used in a variety of solicited or unsolicited polling mechanisms.)fjt
300 1004 1876 14 (It should be recognized that clock synchronization requires by its nature long periods and mult)fjt
2176 1004 75 0 (iple)fjt
300 945 1911 13 (comparisons in order to maintain accurate timekeeping. While only a few measurements are usual)fjt
2211 945 39 0 (ly)fjt
300 887 1884 17 (adequate to reliably determine local time to within a second or so, periods of many hours and doz)fjt
2184 887 66 0 (ens)fjt
300 829 1871 15 (of measurements are required to resolve oscillator drift and maintain local time to the order )fjt
2171 829 79 1 (of a)fjt
300 771 1950 14 (millisecond. Thus, the accuracy achieved is directly dependent on the time taken to achieve it.)fjt
300 712 1897 12 (Fortunately, the frequency of measurements can be quite low and almost always non-intrusive)fjt
2197 712 53 1 ( to)fjt
300 654 447 2 (normal net operations.)fjt
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300 457 1950 18 (In what may be the most common client/server model a client sends an NTP message to one or more)fjt
300 399 1740 13 (servers and processes the replies as received. The server interchanges addresses and ports, )fjt
2040 399 210 0 (overwrites)fjt
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1163 2237 174 0 (Network)fjt
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950 2113 650 3 (Figure 1. Implementation Model)fjt
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300 2979 230 0 (RFC-1119)fjt
1024 2979 504 2 (Network Time Protocol)fjt
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