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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<!-- UDP.html (C) K. J. Turner 18/12/14 -->
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>User Datagram Protocol</title>
<link rev="made" href="http://www.cs.stir.ac.uk/~kjt/"/>
<script type="text/javascript" language="JavaScript">
<!--
var simulator;
var spA;
var dpA;
var spB;
var dpB;
function valid(port, address, user) {
if (address < 0 || address > 65535) {
alert ("Port address for User " + user + " must be in range 0-65535");
return false;
}
else
return true;
}
function set() {
spA = document.settings.SourcePortA.value.toString();
dpA = document.settings.DestPortA.value.toString();
spB = document.settings.SourcePortB.value.toString();
dpB = document.settings.DestPortB.value.toString();
if (valid("source", spA, "A") && valid("destination", dpA, "A") &&
valid("source", spB, "B") && valid("destination", dpB, "B")) {
simulator.setParameter("sourcePortA", spA);
simulator.setParameter("destPortA", dpA);
simulator.setParameter("sourcePortB", spB);
simulator.setParameter("destPortB", dpB);
simulator.updateActionList();
}
}
//-->
</script>
</head>
<body background="simulator.jpeg"
onload="simulator=document.ProtocolSimulator; set();">
<div style="text-align: center">
<h1>User Datagram Protocol Simulator</h1>
<img src="simulator.gif" alt="Simulator Logo"/>
</div>
<h2>Protocol Description</h2>
<p>
UDP (User Datagram Protocol) is a simple connection-less protocol for
transferring datagrams in either direction between a pair of user ports.
Each datagram is identified by its source and destination port numbers
(in the range 0 to 65535).
</p>
<h2>Protocol Parameters</h2>
<form name="settings">
<center>
<table cellspacing="5">
<tr>
<td align="right">User A Source Port</td>
<td><input type="text" name="SourcePortA" value="11" size="5"/></td>
<td align="right">User A Destination Port</td>
<td><input type="text" name="DestPortA" value="22" size="5"/> </td>
</tr>
<tr>
<td align="right">User B Source Port</td>
<td><input type="text" name="SourcePortB" value="33" size="5"/></td>
<td align="right">User B Destination Port</td>
<td><input type="text" name="DestPortB" value="44" size="5"/></td>
</tr>
<tr>
<td align="center" colspan="4">
<input type="button" name="btnSet" value="Change Settings"
onclick="set()"/>
</td>
</tr>
</table>
</center>
</form>
<h2>Protocol Simulation</h2>
<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(Src,Dst,Dn)</em> and receive data transmissions as
<em>DatInd(Src, Dst,Dn)</em>. Data messages are simply numbered <em>D0</em>,
<em>D1</em>, etc. in sequence for each user; no explicit data content is
given. Each user request leads to the protocol message
<em>DT(Src,Dst,Dn)</em> that gives the source port, destination port and
data message number.
</p>
<center>
<applet code="simulator.ProtocolSimulator.class"
archive="ProtocolSimulator.jar" width="750" height="700"
name="ProtocolSimulator">
<param name="protocol" value="UDP"/>
</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>