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diff --git a/contrib/ntp/html/index.htm b/contrib/ntp/html/index.htm new file mode 100644 index 0000000..a676c87 --- /dev/null +++ b/contrib/ntp/html/index.htm @@ -0,0 +1,201 @@ +<HTML><HEAD><TITLE> +The Network Time Protocol (NTP) Distribution +</TITLE></HEAD><BODY><H3> +The Network Time Protocol (NTP) Distribution +</H3> + +<IMG align=left SRC=pic/barnstable.gif>From <i>pogo</i>, Walt Kelly + +<p>Pleased to meet you. +<BR clear=left><HR> + +<H4>Introduction</H4> + +Note: The software contained in this distribution is available without +charge under the conditions set forth in the <A +HREF=copyright.htm>Copyright Notice</A>. + +<P>The Network Time Protocol (NTP) is used to synchronize the time of a +computer client or server to another server or reference time source, +such as a radio or satellite receiver or modem. It provides client +accuracies typically within a millisecond on LANs and up to a few tens +of milliseconds on WANs relative to a primary server synchronized to +Coordinated Universal Time (UTC) via a Global Positioning Service (GPS) +receiver, for example. Typical NTP configurations utilize multiple +redundant servers and diverse network paths, in order to achieve high +accuracy and reliability. Some configurations include cryptographic +authentication to prevent accidental or malicious protocol attacks. + +<P>Background information on computer network time synchronization can +be found on the <A HREF=exec.htm>Executive Summary - Computer Network +Time Synchronization</A> page. Discussion on protocol conformance issues +and interoperability with previous NTP versions can be found in the <A +HREF=biblio.htm>Protocol Conformance Statement</A> page. Discussion on +year-2000 issues can be found in the <A HREF=y2k.htm>Year 2000 +Conformance Statement page</A>. Background information, bibliography and +briefing slides suitable for presentations can be found in the <A +HREF=http://www.eecis.udel.edu/~mills/ntp.htm> Network Time +Synchronization Project</A> page. + +<H4>Building and Installing NTP</H4> + +The <A HREF=build.htm>Building and Installing the Distribution +</A>page presents an overview of the procedures for compiling the +distribution and installing it on a typical client or server. The build +procedures inspect the system hardware and software environment and +automatically select the appropriate options for that environment. While +these procedures work with most computers and operating systems marketed +today, exceptions requiring manual intervention do exist, as documented +in the <A HREF=config.htm>Configuration Options </A>and <A +HREF=release.htm>Release Notes </A>pages. + +<P>Bringing up a NTP primary server requires a radio or satellite +receiver or modem. The distribution includes hardware drivers for over +two dozen radio clocks and modem services. A list of the particular +receivers and modem drivers supported in the distribution is given in +the <A HREF=refclock.htm>Reference Clock Drivers </A>page. For most +popular workstations marketed by Digital, Sun and Hewlett Packard, as +well as widely available Unix clones such as FreeBSD and Linux, the +automatic build procedures select all drivers that run on the target +machine. While this increases the size of the executable binary +somewhat, individual drivers can be included or excluded using the +configure utility documented in the Configuration Options page. + +<H4>Configuring Clients and Servers</H4> +<p>NTP is by its very nature a complex distributed network application +and can be configured and used for a great many widely divergent +timekeeping scenarios. The documentation presented on these pages +attempts to cover the entire suite of configuration, operation and +maintenance facilities which this distribution supports. However, most +applications will need only a few of these facilities. If this is the +case, the <a href=quick.htm>Quick Start</a> page may be useful to get a +simple workstation on the air with an existing server. + +<p>However, in order to participate in the existing NTP synchronization +subnet and obtain accurate, reliable time, it is usually necessary to +construct an appropriate configuration file, commonly called +<TT>ntp.conf</TT>, which establishes the servers and/or external +receivers or modems to be used by this particular machine. Directions +for constructing this file are in the <A HREF=notes.htm>Notes on +Configuring NTP and Setting up a NTP Subnet </A>page. However, in many +common cases involving simple network topologies and workstations, the +file data can be specified entirely on the command line. + +<P>The most important factor in providing accurate, reliable time is the +selection of modes and servers to be used in the configuration file. NTP +support for one or more computers is normally engineered as part of the +existing NTP synchronization subnet. The existing NTP subnet consists of +a multiply redundant hierarchy of servers and clients, with each level +in the hierarchy identified by stratum number. Primary servers operate +at stratum one and provide synchronization to secondary servers +operating at stratum two and so on to higher strata. In this hierarchy, +clients are simply servers that have no dependents. + +<P>The NTP subnet in early 1998 includes 70 public primary (stratum 1) +servers synchronized directly to UTC by radio, satellite or modem and +located in every continent of the globe, except Antarctica (soon). +Normally, client workstations and servers with a relatively small number +of clients do not synchronize to primary servers. There are 106 public +secondary (stratum 2) servers synchronized to the primary servers and +providing synchronization to a total in excess of 100,000 clients and +servers in the Internet. The current lists are maintained in the <A +HREF=http://www.eecis.udel.edu/~mills/ntp/index.htm>Information on Time +and Frequency Services</A> page, which is updated frequently. There are +numerous private primary and secondary servers not normally available to +the public as well. You are strongly discouraged from using these +servers, since they sometimes hide in little ghettos behind dinky links +to the outside world and your traffic can bring up expensive ISDN lines, +causing much grief and frustration. + +<H4>Resolving Problems</H4> + +Like other things Internet, the NTP synchronization subnets tend to be +large and devilishly intricate, with many opportunities for +misconfiguration and network problems. The NTP engineering model is +specifically designed to help isolate and repair such problems using an +integrated management protocol, together with a suite of monitoring and +debugging tools. There is an optional data recording facility which can +be used to record normal and aberrant operation, log problems to the +system log facility, and retain records of client access. The <A +HREF=debug.htm>NTP Debugging Techniques </A>and <A +HREF=hints.htm>Hints and Kinks </A>pages contain useful information +for identifying problems and devising solutions. + +<P>Users are requested to report bugs, offer suggestions and contribute +additions to this distribution. The <A HREF=patches.htm>Patching +Procedures </A>page suggests procedures which greatly simplify +distribution updates, while the <A HREF=porting.htm>Porting Hints +</A>page suggest ways to make porting this code to new hardware and +operating systems easier. Additional information on reference clock +driver construction and debugging can be found in the <A +HREF=refclock.htm>Reference Clock Drivers </A>page. Further +information on NTP in the Internet can be found in the <A +HREF=http://www.eecis.udel.edu/~ntp>NTP +web page</A>. + +<H4>Program Manual Pages</H4> + +<ul> + +<li><A HREF=ntpd.htm><TT>ntpd</TT> - Network Time Protocol (NTP) +daemon</A></LI> +<LI><A HREF=ntpq.htm><TT>ntpq</TT> - standard NTP query +program</A></LI> +<LI><A HREF=ntpdc.htm><TT>ntpdc</TT> - special NTP query +program</A></LI> +<LI><A HREF=ntpdate.htm><TT>ntpdate</TT> - set the date and time via +NTP</A></LI> +<LI><A HREF=ntptrace.htm><TT>ntptrace</TT> - trace a chain of NTP +servers back to the primary source</A></LI> +<LI><A HREF=tickadj.htm><TT>tickadj</TT> - set time-related kernel +variables</A></LI> +<LI><A HREF=ntptime.htm><TT>ntptime</TT> - read kernel time +variables</A></LI> + +</ul> + +<H4>Supporting Documentation</H4> + +<ul> + +<LI<A HREF=ntp.htm>NTP Reference Library</A></LI> +<LI><A HREF=copyright.htm>Copyright Notice</A></LI> +<LI><A HREF=exec.htm>Executive Summary - Computer Network Time +Synchronization</A></LI> +<LI><A HREF=biblio.htm>Protocol Conformance Statement</A></LI> +<LI><A HREF=y2k.htm>Year 2000 Conformance Statement</A></LI> +<LI><A HREF=notes.htm>Notes on Configuring NTP and Setting up a NTP +Subnet</A></LI> +<LI><A HREF=release.htm>NTP Version 4 Release Notes</A></LI> +<LI><A HREF=build.htm>Building and Installing the +Distribution</A></LI> +<LI><A HREF=config.htm>Configuration Options</A></LI> +<LI><A HREF=debug.htm>NTP Debugging Techniques</A></LI> +<LI><A HREF=refclock.htm>Reference Clock Drivers</A></LI> +<LI><A HREF=patches.htm>Patching Procedures</A></LI> +<LI><A HREF=hints.htm>Hints and Kinks</A></LI> +<LI><A HREF=porting.htm>Porting Hints</A></LI> + +</ul> + +<H4>Application Notes</H4> + +<ul> + +<LI><A HREF=prefer.htm>Mitigation Rules and the <TT>prefer</TT> +Keyword</A></LI> +<LI><A HREF=assoc.htm>Association Management</A></LI> +<LI><A HREF=pps.htm>Pulse-per-second (PPS) Signal Interfacing</A></LI> +<LI><A HREF=gadget.htm>Gadget Box PPS Level Converter and CHU +Modem</A></LI> +<LI><A HREF=measure.htm>Time and Time Interval Measurement with +Application to Computer and Network Performance Evaluation</A></LI> +<LI><A HREF=kern.htm>A Kernel Model for Precision Timekeeping</A></LI> +<LI><A HREF=kernpps.htm>A Kernel Programming Interface for Precision +Time Signals</A></LI> + +</ul> + +<hr><a href=index.htm><img align=left src=pic/home.gif></a><address><a +href=mailto:mills@udel.edu> David L. Mills <mills@udel.edu></a> +</address></a></body></html> |
