1181834Sroberto<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 2181834Sroberto<html> 3280849Scy<head> 4280849Scy<meta http-equiv="content-type" content="text/html;charset=iso-8859-1"> 5280849Scy<meta name="generator" content="HTML Tidy, see www.w3.org"> 6280849Scy<title>ntpdsim - Network Time Protocol (NTP) Simulator</title> 7280849Scy<link href="scripts/style.css" type="text/css" rel="stylesheet"> 8280849Scy</head> 9280849Scy<body> 10280849Scy<h3><tt>ntpdsim</tt> - Network Time Protocol (NTP) Simulator</h3> 11280849Scy<img src="pic/oz2.gif" alt="gif" align="left"><a href="http://www.eecis.udel.edu/%7emills/pictures.html">from <i>The Wizard of Oz</i>, L. Frank Baum</a> 12280849Scy<p>All in a row.</p> 13280849Scy<p>Last update: 14280849Scy <!-- #BeginDate format:En2m -->31-Jan-2014 06:54<!-- #EndDate --> 15280849Scy UTC</p> 16280849Scy<br clear="left"> 17280849Scy<h4>Related Links</h4> 18280849Scy<script type="text/javascript" language="javascript" src="scripts/manual.txt"></script> 19280849Scy<h4>Table of Contents</h4> 20280849Scy<ul> 21280849Scy <li><a href="#description">Description</a></li> 22280849Scy <li><a href="#configuration">Configuration</a></li> 23280849Scy <li><a href="#sample">Sample Configuration File</a></li> 24280849Scy</ul> 25280849Scy<hr> 26280849Scy<h4 id="description">Description</h4> 27280849Scy<p>The ntpdsim program is used to simulate and study the behavior of an NTP daemon that derives its time from a number of different simulated time sources (servers). Each simulated server can be configured to have a different time offset, frequency offset, propagation delay, processing delay, network jitter and oscillator wander.</p> 28280849Scy<p>The ntpdsim program runs all the same selection, mitigation, and discipline 29280849Scy algorithms as the actual ntpd daemon at the client. (It actually 30280849Scy uses the same code). However, the input/output routines and servers are simulated. 31280849Scy That is, instead of sending the client messages over the network 32280849Scy to the actual servers, the client messages are intercepted by the ntpdsim 33280849Scy program, which then generates the replies to those messages. The reply messages 34280849Scy are carefully "inserted" into the input queue of the client at the right time 35280849Scy according to the specified server properties (like propagation delay).</p> 36280849Scy<p>Each simulated server runs according to a specified script that describes the server properties at a particular time. Each script consists of a series of consecutive acts. Each act runs for a particular duration and specifies the frequency offset, propagation delay, processing delay, network jitter and oscillator wander of the server for that duration. Once the duration of an act expires, the simulated server reconfigures itself according to the properties specified in the next act.</p> 37280849Scy<h4 id="configuration">Configuration</h4> 38280849Scy<p>The ntpdsim program is configured by providing a configuration file at startup. The crux of the simulator configuration is specified using a <tt>simulate</tt> command, the syntax of which is given below. Note that all time quantities are in seconds and all frequency quantities are in parts per million (PPM):</p> 39280849Scy<p><<i>simulate_command</i>> ::= <tt>simulate</tt> { <<i>init_statement_list</i>> <<i>server_list</i>> }<br> 40280849Scy <<i>init_statement_list</i>> ::= <init_statement_list> <init_statement> ; | <init_statement> ;<br> 41280849Scy <<i>init_statement</i>> ::= <tt>beep_delay</tt> = <number> | <tt>simulation_duration</tt> = <number><br> 42280849Scy <<i>server_list</i>> ::= <<i>server_list</i>> <server> | <server><br> 43280849Scy <<i>server_list</i>> ::= <tt>server</tt> = <address> { <tt>server_offset</tt> = <number> ; <act_list> }<br> 44280849Scy <<i>act_list</i>> ::= <<i>act_list</i>> <<i>act</i>> | <<i>act</i>><br> 45280849Scy <<i>act</i>> ::= <tt>duration</tt> = <number> { <<i>act_stmt_list</i>> }<br> 46280849Scy <<i>act_stmt_list</i>> ::= <<i>act_stmt_list</i>> <<i>act_stmt</i>> ; | <<i>act_stmt</i>> ;<br> 47280849Scy <<i>act_stmt</i>> ::= <tt>freq_offset</tt> = <number> | <tt>wander</tt> = <number> | <tt>jitter</tt> = <number> | <tt>prop_delay</tt> = <number> | <tt>proc_delay</tt> = <number></p> 48280849Scy<p>In addition to the <tt>simulate</tt> command, other standard NTP configuration commands can be specified. These commands have the same meaning as in the ntpd configuration. Note that newlines are <b>not</b> significant within the <tt>simulate</tt> command even though they are used to mark the end of a normal NTP configuration command. While a newline is an "end of command" terminator for other configuration commands, in the <tt>simulate</tt> stanza <tt>;</tt> (the semicolon) is the "end of command" terminator.</p> 49280849Scy<h4 id="sample">Sample Configuration File</h4> 50280849Scy<p>A sample ntpdsim configuration file is given below. It specifies two simulated servers, each of which has two acts.</p> 51280849Scy<pre> 52181834Sroberto # Client configuration 53181834Sroberto disable kernel 54181834Sroberto server pogo 55181834Sroberto driftfile ./ntp.drift 56181834Sroberto statsdir ./ntpstats/ 57181834Sroberto filegen loopstats type day enable 58181834Sroberto filegen peerstats type day enable 59181834Sroberto 60181834Sroberto # Simulation configuration 61181834Sroberto simulate { 62280849Scy simulation_duration = 86400; 63280849Scy beep_delay = 3600; 64181834Sroberto 65181834Sroberto # Server 1 66181834Sroberto server = louie.udel.edu { 67280849Scy server_offset = 0; 68181834Sroberto duration = 50000 { 69280849Scy freq_offset = 400; 70280849Scy wander = 1.0; 71280849Scy jitter = 0.001; 72280849Scy prop_delay = 0.001; 73280849Scy proc_delay = 0.001; 74181834Sroberto } 75181834Sroberto duration = 6400 { 76280849Scy freq_offset = 200; 77280849Scy wander = 1.0; 78280849Scy jitter = 0.001; 79280849Scy prop_delay = 0.001; 80280849Scy proc_delay = 0.001; 81181834Sroberto } 82181834Sroberto } 83181834Sroberto 84181834Sroberto # Server 2 85181834Sroberto server = baldwin.udel.edu { 86280849Scy server_offset = 0.02; 87181834Sroberto duration = 10000 { 88280849Scy freq_offset = 400; 89280849Scy wander = 1.0; 90280849Scy jitter = 0.001; 91280849Scy prop_delay = 0.5; 92280849Scy proc_delay = 0.001; 93181834Sroberto } 94181834Sroberto duration = 60000 { 95280849Scy freq_offset = 200; 96280849Scy wander = 1.0; 97280849Scy jitter = 0.05; 98280849Scy prop_delay = 0.005; 99280849Scy proc_delay = 0.001; 100181834Sroberto } 101181834Sroberto } 102280849Scy } 103181834Sroberto </pre> 104280849Scy<hr> 105280849Scy<address> 106280849Scy<a href="mailto:skamboj@udel.edu">Sachin Kamboj</a> 107280849Scy</address> 108280849Scy<script type="text/javascript" language="javascript" src="scripts/footer.txt"></script> 109280849Scy</body> 110181834Sroberto</html> 111
