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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>5.5 Routing Module and Classifier Organization</TITLE><META NAME="description" CONTENT="5.5 Routing Module and Classifier Organization"><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="node56.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node56.html"><LINK REL="previous" HREF="node47.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node47.html"><LINK REL="up" HREF="node39.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node39.html"><LINK REL="next" HREF="node54.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node54.html"></HEAD><BODY ><!--Navigation Panel--><A NAME="tex2html2127" HREF="node54.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node54.html"><IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="file:/usr/share/latex2html/icons/next.png"></A> <A NAME="tex2html2121" HREF="node39.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node39.html"><IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="file:/usr/share/latex2html/icons/up.png"></A> <A NAME="tex2html2115" HREF="node52.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node52.html"><IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="file:/usr/share/latex2html/icons/prev.png"></A> <A NAME="tex2html2123" 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="tex2html2125" 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="tex2html2128" HREF="node54.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node54.html">5.5.1 Routing Module</A><B> Up:</B> <A NAME="tex2html2122" HREF="node39.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node39.html">5. Nodes and Packet</A><B> Previous:</B> <A NAME="tex2html2116" HREF="node52.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node52.html">5.4.5 Replicator</A>   <B> <A NAME="tex2html2124" HREF="node1.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node1.html">Contents</A></B>   <B> <A NAME="tex2html2126" HREF="node590.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node590.html">Index</A></B> <BR><BR><!--End of Navigation Panel--><H1><A NAME="SECTION03250000000000000000"></A><A NAME="sec:node:rtarch"></A><BR>5.5 Routing Module and Classifier Organization</H1><P>As we have seen, a node is essentially a collection ofclassifiers.The simplest node (unicast) contains only one address classifier andone port classifier, as shown in Figure <A HREF="node40.html#fig:node:unicast" tppabs="http://www.isi.edu/nsnam/ns/doc/node40.html#fig:node:unicast">5.1</A>.When one extends the functionality of the node, more classifiers are addedinto the base node, for instance, the multicast node shown inFigure <A HREF="node40.html#fig:node:multicast" tppabs="http://www.isi.edu/nsnam/ns/doc/node40.html#fig:node:multicast">5.2</A>.As more function blocks is added, and each of these blocks requiresits own classifier(s), it becomes important for the node toprovide a <EM>uniform</EM> interface to organize these classifiers and tobridge these classifiers to the route computation blocks.<P>The classical method to handle this case is through classinheritance.For instance, if one wants a node that supports hierarchical routing,one simply derive a Node/Hier from the base node and override theclassifier setup methods to insert hierarchical classifiers.This method works well when the new function blocks are independentand cannot be ``arbitrarily'' mixed. For instance, both hierarchical routing and ad hoc routing use theirown set of classifiers. Inheritance would require that we have Node/Hier that supportsthe former, and Node/Mobile for the latter.This becomes slightly problematic when one wants an ad hoc routingnode that supports hierarchical routing.In this simple case one may use multiple inheritance to solve theproblem, but this quickly becomes infeasible as the number of suchfunction blocks increases. <P>The only method to solve this problem is object composition. The base node needs to define a set of interfaces for classifieraccess and organization. These interfaces should<UL><LI>allow individual routing modules that implement their own classifiers to insert their classifiers into the node;</LI><LI>allow route computation blocks to populate routes to classifiers in all routing modules that need this information, </LI><LI>provide a single point of management for existing routing modules. </LI></UL>In addition, we should also define a uniform interface for routingmodules to connect to the node interfaces, so as to provide asystematic approach to extending node functionality. In this section we will describe the design of routing modules as wellas that of the corresponding node interfaces.<P><BR><HR><!--Table of Child-Links--><A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></A><UL><LI><A NAME="tex2html2129" HREF="node54.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node54.html">5.5.1 Routing Module</A><LI><A NAME="tex2html2130" HREF="node55.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node55.html">5.5.2 Node Interface</A></UL><!--End of Table of Child-Links--><HR><!--Navigation Panel--><A NAME="tex2html2127" HREF="node54.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node54.html"><IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="file:/usr/share/latex2html/icons/next.png"></A> <A NAME="tex2html2121" HREF="node39.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node39.html"><IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="file:/usr/share/latex2html/icons/up.png"></A> <A NAME="tex2html2115" HREF="node52.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node52.html"><IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="file:/usr/share/latex2html/icons/prev.png"></A> <A NAME="tex2html2123" 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="tex2html2125" 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="tex2html2128" HREF="node54.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node54.html">5.5.1 Routing Module</A><B> Up:</B> <A NAME="tex2html2122" HREF="node39.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node39.html">5. Nodes and Packet</A><B> Previous:</B> <A NAME="tex2html2116" HREF="node52.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node52.html">5.4.5 Replicator</A>   <B> <A NAME="tex2html2124" HREF="node1.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node1.html">Contents</A></B>   <B> <A NAME="tex2html2126" 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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