Do you discover that your computer system time gradually become quicker or lag behind after a period of time? It comes from the fact that the crystal or oscillator, which is the time-accounting component, has inaccuracy dimensions in manufacture process. This inaccuracy oscillating frequency translates the error system time, maybe a few seconds deviation during one day. In our living or working environment we need accurate computer information, so precision computer system time is very important, especially in e-commerce, computer network research and MIS systems. In order to deal with this problem, many volunteers organized an internationl group www.ntp.org. This page is the home for NTP software package and the official reference implementation of the NTP protocol.

NTP is a protocol designed to synchronize the clocks of computers over a network and NTP version 3 is an internet draft standard, formalized in RFC 1305. In NTU campus, NTP server calculates the precision time (deviation within 1ms ) from GPS signals and providing users referencing for adjusting computer system time.

※ Network time protocol server operation principle

There is a network time protocol (NTP) server preserving an accuracy time standard, which provides NTP clients or PC system a time adjustment reference.

After NTP clients or PC system time synchronize with the clock of NTP server, no time deviation problem will be happened. The following figure describes the principle:
T1-T0: the Client requests NTP server to provide NTP service (including network transmission time).
T2-T1: NTP server processing time.
T3-T2: the NTP server replies to Client with NTP service information (including network transmission time).
T3-T0: total spending time.
The time delay from Client to NTP server is between T3-T2 to T3-T1.
Using NTU NTP server (URL:ntp.ntu.edu.tw or ntp2.ntu.edu.tw) in NTU campus, the network transmission time is shorter than others, so user can get the most precision network time.

※ Time adjustmnet software download and operation description

Time adjustment software download and operation description (Unix serious)

ftp://www.stdtime.gov.tw/ntp_server/xntp3-5.93.tar.gz

http://www.eecis.udel.edu/~ntp/software.html

ftp://ftp.csie.ncu.edu.tw/Network/ntp/xntp3-5.93.tar.gz

ftp://ftp.csie.ncu.edu.tw/Network/ntp/xntp3.5f.tar.Z

Please decompress the above file and execute the configure command, it will produce Makefile automatically.

Executre make command for cc or gcc compiling. After compiling you have to edit ntp.conf file and execute xntpd.

Time adjustment software download and operation description (Window serious)

NTP software download

※operation instrution

<1>Executing time adjustment software will pop the following figure：

<2>Press the mouse right key above the figure, select 「網路校時設定」will occur the following figure.

In the 時間伺服器位址 block , you can choose any one of the following URLs to key in：

ntp.ntu.edu.tw 、140.112.2.188、ntp2.ntu.edu.tw、 140.112.2.189

then pressing 「立即查詢主機時間」button will complete time adjustment.

<3>program status description：

•Q indicates "Questing NTP server "
•C indicates "Connecting NTP server "
•S indicates "Sending message to NTP server"
•W indicates "Waiting message from NTP server"