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<html><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"><!--Converted with jLaTeX2HTML 2002 (1.62) JA patch-1.4patched version by: Kenshi Muto, Debian Project.LaTeX2HTML 2002 (1.62),original version by: Nikos Drakos, CBLU, University of Leeds* revised and updated by: Marcus Hennecke, Ross Moore, Herb Swan* with significant contributions from: Jens Lippmann, Marek Rouchal, Martin Wilck and others --><HTML><HEAD><TITLE>17.2.6 Error models</TITLE><META NAME="description" CONTENT="17.2.6 Error models"><META NAME="keywords" CONTENT="everything"><META NAME="resource-type" CONTENT="document"><META NAME="distribution" CONTENT="global"><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"><META NAME="Generator" CONTENT="jLaTeX2HTML v2002 JA patch-1.4"><META HTTP-EQUIV="Content-Style-Type" CONTENT="text/css"><LINK REL="STYLESHEET" HREF="everything.css" tppabs="http://www.isi.edu/nsnam/ns/doc/everything.css"><LINK REL="next" HREF="node206.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node206.html"><LINK REL="previous" HREF="node204.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node204.html"><LINK REL="up" HREF="node199.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node199.html"><LINK REL="next" HREF="node206.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node206.html"></HEAD><BODY ><!--Navigation Panel--><A NAME="tex2html4432" HREF="node206.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node206.html"><IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="file:/usr/share/latex2html/icons/next.png"></A> <A NAME="tex2html4426" HREF="node199.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node199.html"><IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="file:/usr/share/latex2html/icons/up.png"></A> <A NAME="tex2html4420" HREF="node204.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node204.html"><IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="file:/usr/share/latex2html/icons/prev.png"></A> <A NAME="tex2html4428" HREF="node1.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node1.html"><IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="file:/usr/share/latex2html/icons/contents.png"></A> <A NAME="tex2html4430" HREF="node590.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node590.html"><IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index" SRC="file:/usr/share/latex2html/icons/index.png"></A> <BR><B> Next:</B> <A NAME="tex2html4433" HREF="node206.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node206.html">17.2.7 Other configuration options</A><B> Up:</B> <A NAME="tex2html4427" HREF="node199.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node199.html">17.2 Using the satellite</A><B> Previous:</B> <A NAME="tex2html4421" HREF="node204.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node204.html">17.2.5 Trace support</A>   <B> <A NAME="tex2html4429" HREF="node1.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node1.html">Contents</A></B>   <B> <A NAME="tex2html4431" HREF="node590.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node590.html">Index</A></B> <BR><BR><!--End of Navigation Panel--><H2><A NAME="SECTION031426000000000000000"></A><A NAME="sec:satellite_usage_error"></A><BR>17.2.6 Error models</H2><P> error models are described in Chapter <A HREF="node137.html#chap:error_model" tppabs="http://www.isi.edu/nsnam/ns/doc/node137.html#chap:error_model">13</A>. Theseerror models can be set to cause packets to be errored according to variousprobability distributions. These error models are simple and don't necessarily correspond to what would be experienced on an actual satellitechannel (particularly a LEO channel). Users are free to define more sophisticated error models that more closely match a particular satellite environment.<P>The following code provides an example of how to add an error model to alink:<PRE>set em_ [new ErrorModel]$em_ unit pkt$em_ set rate_ 0.02$em_ ranvar [new RandomVariable/Uniform]$node interface-errormodel $em_</PRE>This will add an error model to the receive path of the first interfacecreated on node <TT>$node</TT> (specifically, between the MAC and link layer)-this first interface generally corresponds to the uplink and downlinkinterface for a satellite or a terminal (if only one uplink and/or downlinkexists).To add the error model to a different stack (indexed by ), use the following code:<PRE>$node interface-errormodel $em_ $i</PRE><P><HR><!--Navigation Panel--><A NAME="tex2html4432" HREF="node206.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node206.html"><IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="file:/usr/share/latex2html/icons/next.png"></A> <A NAME="tex2html4426" HREF="node199.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node199.html"><IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="file:/usr/share/latex2html/icons/up.png"></A> <A NAME="tex2html4420" HREF="node204.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node204.html"><IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="file:/usr/share/latex2html/icons/prev.png"></A> <A NAME="tex2html4428" HREF="node1.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node1.html"><IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="file:/usr/share/latex2html/icons/contents.png"></A> <A NAME="tex2html4430" HREF="node590.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node590.html"><IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index" SRC="file:/usr/share/latex2html/icons/index.png"></A> <BR><B> Next:</B> <A NAME="tex2html4433" HREF="node206.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node206.html">17.2.7 Other configuration options</A><B> Up:</B> <A NAME="tex2html4427" HREF="node199.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node199.html">17.2 Using the satellite</A><B> Previous:</B> <A NAME="tex2html4421" HREF="node204.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node204.html">17.2.5 Trace support</A>   <B> <A NAME="tex2html4429" HREF="node1.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node1.html">Contents</A></B>   <B> <A NAME="tex2html4431" HREF="node590.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node590.html">Index</A></B> <!--End of Navigation Panel--><ADDRESS>2003-09-23</ADDRESS></BODY></HTML>⌨️ 快捷键说明
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