65 lines
2.1 KiB
HTML
65 lines
2.1 KiB
HTML
|
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN">
|
||
|
|
<html>
|
||
|
|
|
||
|
|
<head>
|
||
|
|
<meta http-equiv="Content-Type"
|
||
|
|
content="text/html; charset=iso-8859-1">
|
||
|
|
<meta name="Author" content>
|
||
|
|
<meta name="GENERATOR" content="Microsoft FrontPage 2.0">
|
||
|
|
<title>IPM Channel</title>
|
||
|
|
</head>
|
||
|
|
|
||
|
|
<body bgcolor="#C0C0C0" text="#000000" link="#0000EE"
|
||
|
|
vlink="#551A8B" alink="#FF0000">
|
||
|
|
|
||
|
|
<h3>IP Multicast Channel</h3>
|
||
|
|
|
||
|
|
<p><b>Syntax</b></p>
|
||
|
|
|
||
|
|
<p><tt>dp_connect ipm -group </tt><em><tt>ipAddr</tt></em><tt>
|
||
|
|
-myport </tt><em><tt>myPort</tt></em><tt> -ttl </tt><em><tt>numHops</tt></em></p>
|
||
|
|
|
||
|
|
<p><b>Comments</b></p>
|
||
|
|
|
||
|
|
<p>IPM is the multicast version of UDP. It allows any
|
||
|
|
number of machines to join a group and if a message is sent to
|
||
|
|
the group address, all the machines will hear it.</p>
|
||
|
|
|
||
|
|
<ul>
|
||
|
|
<li><i>ipAddr</i> is the IP address of the group.
|
||
|
|
This <b>must</b> be an multicast address in the range of
|
||
|
|
224.0.0.0 to 239.255.255.255.</li>
|
||
|
|
<li><i>myPort</i> is the local port and is optional.</li>
|
||
|
|
<li><i>numHops</i> is the Time To Live value. The
|
||
|
|
multicast packets will only cross <i>numHops</i>-1
|
||
|
|
routers after which they are discarded by the
|
||
|
|
router. To keep all multicast data on the local
|
||
|
|
subnet, use a ttl value of 1. Proper netiquette
|
||
|
|
maintains that this number be as low as possible.
|
||
|
|
It is optional and defaults to 1.</li>
|
||
|
|
</ul>
|
||
|
|
|
||
|
|
<hr>
|
||
|
|
|
||
|
|
<p>One can add and drop IPM group memberships using the
|
||
|
|
fconfigure -group command. See below for examples and please note
|
||
|
|
the use of the plus and minus symbol to signify add or drop. An
|
||
|
|
IPM channel can be a member of any number of multicast groups
|
||
|
|
(although it is usually limited by the OS to 20) so it is not
|
||
|
|
necessary to drop a group in order to add a new one.</p>
|
||
|
|
|
||
|
|
<hr>
|
||
|
|
|
||
|
|
<p><b>Examples</b></p>
|
||
|
|
|
||
|
|
<dl>
|
||
|
|
<dt><tt>dp_connect ipm -group 224.76.0.119</tt></dt>
|
||
|
|
<dt><tt>dp_connect ipm -group 225.23.120.87 -ttl 3</tt></dt>
|
||
|
|
<dt><tt>dp_connect ipm -group 238.1.1.1 -port 1905 -ttl 255</tt></dt>
|
||
|
|
<dt><tt>fconfigure $ipmChan -group +226.54.3.2</tt></dt>
|
||
|
|
<dt><tt>fconfigure $ipmChan -group -232.56.198.6</tt></dt>
|
||
|
|
</dl>
|
||
|
|
</body>
|
||
|
|
</html>
|
||
|
|
|