📄 node192.html
字号:
<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>16.2.2 MobileIP</TITLE><META NAME="description" CONTENT="16.2.2 MobileIP"><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="previous" HREF="node191.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node191.html"><LINK REL="up" HREF="node190.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node190.html"><LINK REL="next" HREF="node193.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node193.html"></HEAD><BODY ><!--Navigation Panel--><A NAME="tex2html4223" HREF="node193.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node193.html"><IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="file:/usr/share/latex2html/icons/next.png"></A> <A NAME="tex2html4217" HREF="node190.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node190.html"><IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="file:/usr/share/latex2html/icons/up.png"></A> <A NAME="tex2html4213" HREF="node191.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node191.html"><IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="file:/usr/share/latex2html/icons/prev.png"></A> <A NAME="tex2html4219" 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="tex2html4221" 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="tex2html4224" HREF="node193.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node193.html">16.3 Lists of changes</A><B> Up:</B> <A NAME="tex2html4218" HREF="node190.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node190.html">16.2 Extensions made to</A><B> Previous:</B> <A NAME="tex2html4214" HREF="node191.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node191.html">16.2.1 wired-cum-wireless scenarios</A>   <B> <A NAME="tex2html4220" HREF="node1.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node1.html">Contents</A></B>   <B> <A NAME="tex2html4222" 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="SECTION031322000000000000000"></A><A NAME="sec:mobileip"></A><BR>16.2.2 MobileIP</H2><P>The wired-cum-wireless extensions for the wireless model paved thepath for supporting wireless MobileIP in . Sun Microsystem's(Charlie Perkins <EM>et al</EM>) MobileIP model was based on ns's wired model(consisting of <TT>Node</TT>'s and <TT>Link</TT>'s) and thus didnot useCMU's mobility model.<P>Here we briefly describe the wireless MobileIP implementation. We hopethat Sun would provide the detailed version of the documentation inthe future.<P>The mobileIP scenario consists of Home-Agents(HA) andForeign-Agents(FA) and have Mobile-Hosts(MH) moving between their HAand FAs.The HA and FA are essentially base-station nodes we have describedearlier. While MHs are basically the mobileNodes described insection <A HREF="node173.html#sec:mobilenode-creation" tppabs="http://www.isi.edu/nsnam/ns/doc/node173.html#sec:mobilenode-creation">16.1.1</A>.The methods and procedures for MobileIP extensions are described inmip.{cc,h}, mip-reg.cc, tcl/lib/ns-mip.tcl andtcl/lib/ns-wireless-mip.tcl.<P><DIV ALIGN="CENTER"><A NAME="fig:mobilenode-wireless-mip"></A><A NAME="6984"></A><TABLE><CAPTION ALIGN="BOTTOM"><STRONG>Figure 16.4:</STRONG>Schematic of a Wireless MobileIP BaseStation Node</CAPTION><TR><TD><DIV ALIGN="CENTER">wireless-mip</DIV></TD></TR></TABLE></DIV>The HA and FA nodes are defined as <TT>MobileNode/MIPBS</TT> having aregistering agent (regagent_) that sends beacon out to themobilenodes, sets up encapsulator and decapsulator, as required andreplies to solicitations from MHs. The MH nodes are defined as <TT>MobileNode/MIPMH</TT> which too have aregagent_ that receives and responds to beacons and sends outsolicitations to HA or FAs. Figure <A HREF="node192.html#fig:mobilenode-wireless-mip" tppabs="http://www.isi.edu/nsnam/ns/doc/node192.html#fig:mobilenode-wireless-mip">16.4</A>illustrates the schematic of a <TT>MobileNode/MIPBS</TT> node. The <TT>MobileNode/MIPMH</TT> node is very similar to this exceptfor the fact that it doesnot have any encapsulator or decapsulator. Asfor the SRNode version of a MH, it doesnot have the hierarchicalclassifiers and the RA agent forms the entry point of the node. SeeFigure <A HREF="node173.html#fig:mobilenode-dsr" tppabs="http://www.isi.edu/nsnam/ns/doc/node173.html#fig:mobilenode-dsr">16.2</A> for model of a SRNode. <P>The <TT>MobileNode/MIPBS</TT> node routinely broadcasts beacon oradvertisement messages out to MHs. A solicitation from a mobilenodegenerates an ad that is send directly to the requesting MH. Theaddress of the base-station sending out beacon is heard by MH and is used as the COA (care-of-address) of the MH. Thus as the MHmoves from its native to foreign domains, its COA changes. Upon receiving reg_request (as reply to ads) from a mobilehost thebase-station checks to see if it is the HA for the MH. If not, it setsup its decapsulator and forwards the reg_request towards the HA ofthe MH. <P>In case the base-station <EM>is</EM> the HA for the requesting MH but theCOA doesnot match its own, it sets up an encapsulator and sendsreg-request-reply back to the COA (address of the FA) who hasforwarded the reg_request to it. so now all packets destined to theMH reaching the HA would be tunneled through the encapsulator whichencapsulates the IP pkthdr with a IPinIP hdr, now destined to the COAinstead of MH. The FA's decapsulator recives this packet, removes theencapsulation and sends it to the MH.<P>If the COA matches that of the HA, it just removes the encapsulator itmight have set up (when its mobilehost was roaming into foreignnetworks) and sends the reply directly back to the MH, as the MH havenow returned to its native domain.<P>The mobilehost sends out solicitations if it doesnot hear any ads from thebase-stations. Upon receiving ads, it changes its COA to the address ofthe HA/FA it has heard the ad from, and replies back to the COA with arequest for registration (<TT>reg-request</TT>).Initially the MH maybe in the range of the HA and receives all pktsdirectly from its COA which is HA in this case. Eventually as the MH moves out of range of its HA and into the a foreigndomain of a FA, the MH's COA changes from its HA to that of the FA. The HAnow sets up an encapsulator and tunnels all pkts destined for MH towardsthe FA. The FA decapsulates the pkts and hands them over to the MH. Thedata from MH destined for the wired world is always routed towards itscurrent COA. An example script for wireless mobileIP can be found attcl/ex/wireless-mip-test.tcl. The simulation consists of a MH movingbetween its HA and a FA. The HA and FA are each connected to a wireddomain on one side and to their wireless domains on the other. TCP flowsare set up between the MH and a wired node. <P><HR><!--Navigation Panel--><A NAME="tex2html4223" HREF="node193.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node193.html"><IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="file:/usr/share/latex2html/icons/next.png"></A> <A NAME="tex2html4217" HREF="node190.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node190.html"><IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="file:/usr/share/latex2html/icons/up.png"></A> <A NAME="tex2html4213" HREF="node191.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node191.html"><IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="file:/usr/share/latex2html/icons/prev.png"></A> <A NAME="tex2html4219" 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="tex2html4221" 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="tex2html4224" HREF="node193.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node193.html">16.3 Lists of changes</A><B> Up:</B> <A NAME="tex2html4218" HREF="node190.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node190.html">16.2 Extensions made to</A><B> Previous:</B> <A NAME="tex2html4214" HREF="node191.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node191.html">16.2.1 wired-cum-wireless scenarios</A>   <B> <A NAME="tex2html4220" HREF="node1.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node1.html">Contents</A></B>   <B> <A NAME="tex2html4222" 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
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -