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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<!-- IP.html (C) K. J. Turner 18/12/14 -->
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>
Internet Protocol
</title>
<link rev="made" href="http://www.cs.stir.ac.uk/~kjt/"/>
<script type="text/javascript" language="JavaScript">
<!--
var simulator;
var userMessageSize;
var maxProtocolMessageSize;
var maxMediumMessageSize;
var lossRate;
function validInteger(name, value, min, max) {
if (!value.match("\\d+") || value < min || value > max) {
alert("Value for " + name + " must be in range " + min + " to " + max);
return false;
}
else
return true;
}
function validFloat(name, value, min, max) {
if (!value.match("\\d+\.\\d+") || value < min || value > max) {
alert("Value for " + name + " must be in range " + min + " to " + max);
return false;
}
else
return true;
}
function set() {
userMessageSize = document.settings.userMessageSize.value;
maxProtocolMessageSize = document.settings.maxProtocolMessageSize.value;
maxMediumMessageSize = document.settings.maxMediumMessageSize.value;
lossRate = document.settings.lossRate.value;
if (validInteger("User Message Size", userMessageSize, 10, 1000) &&
validInteger(
"Maximum Protocol Message Size", maxProtocolMessageSize, 10, 1000) &&
validInteger(
"Maximum Medium Message Size", maxMediumMessageSize, 10, 1000) &&
validFloat("Loss Rate", lossRate, 0.0, 1.0)) {
simulator.setParameter("userMessageSize", userMessageSize);
simulator.setParameter("maxProtocolMessageSize", maxProtocolMessageSize);
simulator.setParameter("maxMediumMessageSize", maxMediumMessageSize);
simulator.setParameter("lossRate", lossRate);
if (document.settings.Misordering.checked)
simulator.setParameter("misordering","true");
else
simulator.setParameter("misordering","false");
simulator.updateActionList();
}
}
//-->
</script>
</head>
<body background="simulator.jpeg"
onload="simulator=document.ProtocolSimulator; set();">
<div style="text-align: center">
<h1>Internet Protocol Simulator</h1>
<img src="simulator.gif" alt="Simulator Logo"/>
</div>
<p>
IP (Internet Protocol) a simple connection-less protocol for transferring
datagrams in either direction between a pair of hosts.
</p>
<p>
The protocol simulation shows a time-sequence diagram with users A and B,
protocol entities A and B that support them, and a communications medium
that carries messages. Users request data transmissions with
<em>DatReq(DATA<strong>n</strong>),</em> and receive data transmissions
as <em>DatInd(DATA<strong>n</strong>)</em>. Protocol messages are sent as
<em>DT(MID,Offset,Length)</em> that gives the message identifier
<em>n</em>, its byte offset relative to the whole user message, and the
length of the message (fragment). The user message size may exceed the
maximum protocol message size, which leads to fragmentation. The maximum
protocol message size may also exceed that for the medium, in which case
there may be further fragmentation. Each fragment is followed by `+&#39;
to mean that it is not the last; the very last fragment is followed by
`-&#39;. (This is equivalent to the <em>More Fragments</em> flag in the
protocol.)
</p>
<p>
You may choose if the receiving protocol entity should time out a partly
received message. Since the simulation does not run in real-time, a
message&#39;s Time-To-Live (TTL) may expire as soon as it has been
received in part. There is no control over fragmentation in the
simulation; this is handled automatically based on the protocol
parameters. Messages may also be randomly lost or misordered, based on
the parameter settings.
</p>
<h2>Protocol Parameters</h2>
<p>
The following settings are adequate for a simple simulation. For a more
advanced exploration, choose different options and click <em>Change
Settings</em>.
</p>
<form name="settings">
<center>
<table cellpadding="5">
<tr>
<td align="right">User Message Size (10 to 1000):</td>
<td>
<input type="text" name="userMessageSize" value="400" size="4"/>
</td>
</tr>
<tr>
<td align="right">Maximum Protocol Message Size (10 to 1000):</td>
<td>
<input type="text" name="maxProtocolMessageSize" value="200"
size="4"/>
</td>
</tr>
<tr>
<td align="right">Maximum Medium Message Size (10 to 1000):</td>
<td>
<input type="text" name="maxMediumMessageSize" value="100"
size="4"/>
</td>
</tr>
<tr>
<td align="right">Loss Rate (0.0 = lose none, 1.0 = lose all):</td>
<td><input type="text" name="lossRate" value="0.2" size="4"/> </td>
</tr>
<tr>
<td align="right">Medium Message Misordering</td>
<td align="left">
<input type="checkbox" name="Misordering" checked="checked"/>
</td>
</tr>
<tr>
<td align="center" colspan="2">
<input type="button" name="btnSet" value="Change Settings"
onclick="set()"/>
</td>
</tr>
</table>
</center>
</form>
<h2>Protocol Simulation</h2>
<center>
<applet code="simulator.ProtocolSimulator.class"
archive="ProtocolSimulator.jar" width="750" height="700"
name="ProtocolSimulator">
<param name="protocol" value="IP"/>
</applet>
</center>
<hr/>
<p>
<a href="index.html"><img src="uparrow.gif" alt="Up Arrow"/></a>
Up one level to <a href="index.html">Protocol Simulators</a>
</p>
</body>
</html>