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This instproc return <TT>addr</TT>, the address required to attach a receiver to this source. <TT>place_source</TT> calls the Simulator instproc PLMbuild_source_set thatcreates as many Application/Traffic/CBR_PP instances as there are layers (in the following we call aninstance of the class Application/Traffic/CBR_PP a layer). Each layer corresponds to adifferent multicast group. <P>To speed up the simulations when the PLM sources start we use thefollowing trick:At , <TT>PLMbuild_source_set</TT> restricts eachlayer to sendonly one packet (<TT>maxpkts_</TT> set to 1). That allows to build the multicast trees- one multicast tree per layer - without flooding the whole network. Indeed,each layer only sends one packet to build the corresponding multicast tree. <P>The multicast trees take at most the maximum RTT of the network to be established andmust be established before <TT>t</TT>, the PLM source starting time. Therefore,<TT>t</TT> must be carrefully chosen, otherwise the source sends a large number of useless packets. However, as we just need to start the PLM source after the multicast trees are estabished,<TT>t</TT> can be largely overestimated. At time <TT>t</TT>, we set <I>maxpkts_</I> to 268435456 for all the layers.<P>It is fundamental, in order to have persistent multicast trees, that theprune timeout is set to a large value. For instance, with DM routing: <PRE> DM set PruneTimeout 1000</PRE><P>Each layer of a same PLM source has the same flow id <TT>fid_</TT>. Consequently,each PLM source is considered as a single flow for a Fair Queueingscheduler. The PLM code manages automatically the <TT>fid_</TT> to prevent differentsources to have the same <TT>fid_</TT>. The <TT>fid_</TT> starts at 1 for the firstsource and is increased by one for each new source. Be careful to avoid otherflows (for instance concurrent TCP flows) to have the same <TT>fid_</TT> than thePLM sources. Additionally, If you consider <TT>fid_</TT> larger than 32, do notforget to increase the <TT>MAXFLOW</TT> in fq.cc (<TT>MAXFLOW</TT> must be setto the highest <TT>fid_</TT> considered in the simulation).<P><HR><!--Navigation Panel--><A NAME="tex2html8511" HREF="node465.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node465.html"><IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="file:/usr/share/latex2html/icons/next.png"></A> <A NAME="tex2html8505" HREF="node463.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node463.html"><IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="file:/usr/share/latex2html/icons/up.png"></A> <A NAME="tex2html8499" HREF="node463.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node463.html"><IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="file:/usr/share/latex2html/icons/prev.png"></A> <A NAME="tex2html8507" 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="tex2html8509" 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="tex2html8512" HREF="node465.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node465.html">34.3.2 Instantiation of a</A><B> Up:</B> <A NAME="tex2html8506" HREF="node463.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node463.html">34.3 Architecture of the</A><B> Previous:</B> <A NAME="tex2html8500" HREF="node463.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node463.html">34.3 Architecture of the</A>   <B> <A NAME="tex2html8508" HREF="node1.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node1.html">Contents</A></B>   <B> <A NAME="tex2html8510" 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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