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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" []>
<!-- "DTD/docbookx.dtd" []> -->
<article id="Mobile-IPv6-HOWTO">
<articleinfo>
<!-- Article Title -->
<title>Linux Mobile IPv6 HOWTO</title>
<titleabbrev>mipv6</titleabbrev>
<author>
<firstname>Lars</firstname>
<surname>Strand</surname>
<affiliation>
<!-- Valid email -->
<address><email>lars (at) unik no</email></address>
</affiliation>
</author>
<authorinitials>LKS</authorinitials>
<!-- All dates specified in ISO "YYYY-MM-DD" format -->
<pubdate>2004-04-20</pubdate>
<!-- Most recent revision goes at the top; list in descending order -->
<revhistory id="revhistory">
<revision>
<revnumber>1.2</revnumber>
<date>2004-04-20</date>
<authorinitials>LKS</authorinitials>
<revremark>Updated links. Changed lisence back to <ulink
url="http://www.gnu.org/copyleft/fdl.html">GFDL</ulink></revremark>
</revision>
<revision>
<revnumber>1.1</revnumber>
<date>2004-02-04</date>
<authorinitials>LKS</authorinitials>
<revremark>Added "Travelling through several foregin LAN's"
and "Returning home". Some cleanup and restructuring.</revremark>
</revision>
<revision>
<revnumber>1.0</revnumber>
<date>2003-12-02</date>
<authorinitials>TMM</authorinitials>
<revremark>Reviewed by LDP</revremark>
</revision>
<revision>
<revnumber>0.5.2</revnumber>
<date>2003-11-26</date>
<authorinitials>LKS</authorinitials>
<revremark>A lot of cleanup. Thanks to John Levon levon [at]
movementarian.org</revremark>
</revision>
<revision>
<revnumber>0.5.1</revnumber>
<date>2003-11-22</date>
<authorinitials>LKS</authorinitials>
<revremark>Changed the license from <ulink
url="http://www.gnu.org/copyleft/fdl.html"> GFDL </ulink> to
<ulink url="http://www.opencontent.org/openpub/"> OPL
</ulink> due to some GFDL <ulink
url="http://people.debian.org/~srivasta/Position_Statement.xhtml">
problems.</ulink></revremark>
</revision>
<revision>
<revnumber>0.5</revnumber>
<date>2003-11-18</date>
<authorinitials>LKS</authorinitials>
<revremark>Converted to XML Docbook. Some cleanup.</revremark>
</revision>
<revision>
<revnumber>0.4</revnumber>
<date>2002-11-07</date>
<authorinitials>LKS</authorinitials>
<revremark>Fixed some errors + update. Thanks to Henrik Petander
petander (at) tcs hut fi.</revremark>
</revision>
<revision>
<revnumber>0.3.1</revnumber>
<date>2003-11-03</date>
<authorinitials>LKS</authorinitials>
<revremark>Updated to MIPL relase 1.0 (kernel 2.4.22).</revremark>
</revision>
<revision>
<revnumber>0.3</revnumber>
<date>2003-08-05</date>
<authorinitials>LKS</authorinitials>
<revremark>Initial release.</revremark>
</revision>
</revhistory>
<!-- Provide a good abstract; a couple of sentences is sufficient -->
<abstract>
<para>
This document describes the software and procedures to set up
and use mobile IPv6 for Linux. </para>
</abstract>
</articleinfo>
<!-- ##################################################### -->
<sect1 id="intro">
<title>Introduction</title>
<para>
This document describes the software and procedures to set up and
use mobile IPv6 for Linux. The <ulink
url="http://www.ietf.org/internet-drafts/draft-ietf-mobileip-ipv6-24.txt">
"Mobility Support in IPv6" draft </ulink> answers the
<emphasis>what</emphasis> and <emphasis>why</emphasis> of mobile IP:
</para>
<!-- ################## -->
<sect2 id="WhatisMIPv6">
<title>What is Mobile IP?</title>
<para>
<quote>Each mobile node is always identified by its home
address, regardless of its current point of attachment to the
Internet. While situated away from its home, a mobile node is also
associated with a care-of address, which provides information
about the mobile node's current location. IPv6 packets addressed
to a mobile node's home address are transparently routed to its
care-of address via the mobile nodes Home Agent (HA). The
protocol enables IPv6 nodes to cache the binding of a mobile
node's home address with its care-of address, and then to send any
packets destined for the mobile node directly to it at this
care-of address.</quote> --- draft-ietf-mipv6-24, page 1-2.
</para>
</sect2>
<!-- ################## -->
<sect2 id="WhyMIPv6">
<title>Why Mobile IP?</title>
<para>
<quote>Without specific support for mobility in IPv6, packets destined to a
mobile node (host or router) would not be able to reach it while the
mobile node is away from its home link (the link on which its home
IPv6 subnet prefix is in use), since routing is based on the subnet
prefix in a packet's destination IP address. In order to continue
communication in spite of its movement, a mobile node could change its
IP address each time it moves to a new link, but the mobile node would
then not be able to maintain transport and higher-layer connections
when it changes location. Mobility support in IPv6 is particularly
important, as mobile computers are likely to account for a majority or
at least a substantial fraction of the population of the Internet
during the lifetime of IPv6.</quote> --- draft-ietf-mipv6-24, page 6.
</para>
<para>
For all the details, read the <ulink
url="http://www.ietf.org/internet-drafts/draft-ietf-mobileip-ipv6-24.txt">
"Mobility Support in IPv6" draft</ulink>
</para>
</sect2>
<!-- ################## -->
<sect2 id="HowWork">
<title>How does it work?</title>
<mediaobject id="mobileIP">
<imageobject>
<imagedata fileref="images/Mobile-IP.png" format="PNG"
width="520" align="center" scalefit="1"/>
</imageobject>
<textobject>
<phrase>Mobile IP</phrase>
</textobject>
<caption>
<para>Mobile IP</para>
</caption>
</mediaobject>
<para>
<orderedlist>
<listitem>
<para> The Mobile Node (MN) travels to a foreign network and gets a
new care-of-address.</para>
</listitem>
<listitem>
<para> The MN performs a binding update to its Home Agent (HA) (the
new care-of-address gets registered at HA). HA sends a binding
acknowledgement to MN.</para>
</listitem>
<listitem>
<para>A Correspondent Node (CN) wants to contact the MN. The HA
intercepts packets destined to the MN.</para>
</listitem>
<listitem>
<para>The HA then tunnels all packets to the MN from the CN using
MN's care-of-address.</para>
</listitem>
<listitem>
<para>When the MN answers the CN, it may use its current
care-of-address (and perform a binding to the CN) and communicate
with the CN directly (optimized routing) or it can tunnel all its
packets through the HA.</para>
</listitem>
</orderedlist>
</para>
<para>See figure <link linkend="mobileIP">"Mobile IP"</link> for
an explanation.
</para>
</sect2>
</sect1>
<!-- ##################################################### -->
<sect1 id="IPv6">
<title>IPv6</title>
<para>IP version 6 (IPv6) is a new version of the Internet Protocol,
designed as the successor to IP version 4 (IPv4) <ulink
url="http://www.ietf.org/rfc/rfc791.txt">[RFC-791]</ulink>. The
changes from IPv4 to IPv6 fall primarily into the following
categories:
</para>
<itemizedlist>
<listitem>
<para>Expanded addressing capabilities </para>
</listitem>
<listitem>
<para>Header format simplification</para>
</listitem>
<listitem>
<para>Improved support for extensions and options</para>
</listitem>
<listitem>
<para>Flow labeling capability</para>
</listitem>
<listitem>
<para>Authentication and privacy capabilities</para>
</listitem>
</itemizedlist>
<para><emphasis>You should have basic knowledge of IPv6 stateless
auto-configuring to fully understand how 'mobile IPv6' (MIPv6)
works. You can read up on IPv6 Stateless Address Autoconfiguration
in <ulink
url="http://www.ietf.org/rfc/rfc2462.txt">[RFC2462]</ulink>.
</emphasis>
</para>
<para>For more information on IPv6 in general, visit the <ulink
url="http://www.ietf.org/html.charters/ipv6-charter.html">IETF's IPv6
Working Group</ulink>.
</para>
</sect1>
<!-- ##################################################### -->
<sect1 id="MIPv6">
<title>Mobile IPv6 for Linux</title>
<para>There are currently two Mobile IPv6 Linux implementations
available. The Lancaster University in the UK has the oldest(?)
implementation (<ulink url="http://www.cs-ipv6.lancs.ac.uk/MobileIP/">
http://www.cs-ipv6.lancs.ac.uk/MobileIP/</ulink>). The latest kernel
supported is 2.1.90, and is compatible with IETF mobile IPv6 draft-v5
(the current revision is v24). The code and website has not been
updated since 1998, so it is considered obsolete. </para>
<para>The other implementation, which is up-to-date, is Helsinki
University of Technology's MIPL project. The latest supported
kernel is 2.4.22, and they have patches for the upcoming 2.6
kernel (see the FAQ). Visit <ulink
url="http://www.mobile-ipv6.org/">
http://www.mobile-ipv6.org/</ulink> for papers, software or to
browse the mail archive. </para>
<!-- ################## -->
<sect2 id="patch">
<title>Patching the kernel</title>
<para>The MIPL MIPv6 implementation requires a kernel patch. The
implementation modifies the IPv6 kernel stack, so a kernel recompile
is necessary. The installation process is well documented, but I
will give a brief step-by-step howto. </para>
<para><emphasis>Please note! The need for two different kernels, one for MN and
one for HA, is obsolete. Just compile support for MN and HA in the
same kernel. It is not possible to run as both an MN and an HA at
the same time; which mode is chosen depends on which of the modules
are loaded.</emphasis>
</para>
<para>
<orderedlist>
<listitem>
<para> Download the latest Linux MIPv6 source code from
<ulink url="http://www.mobile-ipv6.org/">
http://www.mobile-ipv6.org/</ulink>. The latest release today is:
<emphasis>mipv6-1.0-v2.4.22</emphasis>. The last four numbers
corresponds to the Linux kernel the patch should be applied to:
</para>
<screen>
# cd /usr/local/src
# wget http://www.mobile-ipv6.org/download/mipv6-1.0-v2.4.22.tar.gz
# tar zxfv mipv6-1.0-v2.4.22.tar.gz
</screen>
</listitem>
<listitem>
<para> Download and unpack the correspondent Linux kernel version
from <ulink url="ftp://ftp.kernel.org">ftp.kernel.org</ulink>:
</para>
<screen>
# cd /usr/src
# wget ftp://ftp.kernel.org/pub/linux/kernel/v2.4/linux-2.4.22.tar.bz2
# tar jxvf linux-2.4.22.tar.bz2
# ln -s linux-2.4.22 linux
# cd linux
</screen>
</listitem>
<listitem>
<para>Apply the MIPv6 patch:</para>
<screen>
# patch -p1 --dry-run &lt; /usr/local/src/mipv6-1.0-v2.4.22/mipv6-1.0-v2.4.22.patch
</screen>
<para>The --dry-run option checks that the patch will apply
correctly. If you get any failed hunks, you should
<emphasis>not</emphasis> proceed. If everything went fine do:
</para>
<screen>
# patch -p1 &lt; /usr/local/src/mipv6-1.0-v2.4.22/mipv6-1.0-v2.4.22.patch
</screen>
</listitem>
<listitem>
<para> Now your kernel tree is ready for configuration. Run your
favorite <command>make *config</command>. The MIPv6 options are under
<quote>Networking Options</quote>. The following options should be present in
<emphasis><quote>.config</quote></emphasis>:</para>
<screen>
CONFIG_EXPERIMENTAL=y
CONFIG_SYSCTL=y
CONFIG_PROC_FS=y
CONFIG_MODULES=y
CONFIG_NET=y
CONFIG_NETFILTER=y
CONFIG_UNIX=y
CONFIG_INET=y
CONFIG_IPV6=m
CONFIG_IPV6_SUBTREES=y
CONFIG_IPV6_IPV6_TUNNEL=m
CONFIG_IPV6_MOBILITY=m
CONFIG_IPV6_MOBILITY_MN=m
CONFIG_IPV6_MOBILITY_HA=m
</screen>
<para> Since MIPL is still a work-in-progress you might want to
enable:</para>
<screen>
CONFIG_IPV6_MOBILITY_DEBUG=y
</screen>
<para> With debug messages it is easier to figure out what
happened when something goes wrong. Also, when reporting a bug,
debug messages are very helpful.</para>
<para>To be sure you have all the correct options, you can run
<userinput>chkconf_kernel.sh</userinput>, which is a small shell
script included in the MIPL tarball.</para>
</listitem>
<listitem>
<para> Next you should compile and install your kernel.</para>
<para> Hint: To easily distinguish this kernel from other
kernels, you can change the <quote>EXTRAVERSION</quote> variable
in the <userinput>/usr/src/linux/Makefile</userinput> to for
example <quote>-MIPv6-1</quote>.</para>
</listitem>
</orderedlist>
</para>
<para>Read the <ulink
url="http://tldp.org/HOWTO/Kernel-HOWTO/">Linux Kernel
HOWTO</ulink> for detailed instruction on how to patch, compile and
install your new kernel.</para>
</sect2>
<!-- ################## -->
<sect2 id="userspace">
<title>Userspace tools</title>
<para>The userspace tool <userinput>mipdiag</userinput>, config
files and init scripts must be installed for the module to work
correctly:</para>
<screen>
# cd /usr/local/src/mipv6-1.0-v2.4.22
# ./configure
# make &amp;&amp; make install
</screen>
</sect2>
<!-- ################## -->
<sect2 id="dev">
<title>MIPv6 device node</title>
<para>The MIPv6 module also needs a new device node entry. Issue
the command:</para>
<screen>
# mknod /dev/mipv6_dev c 0xf9 0
</screen>
</sect2>
<!-- ################## -->
<sect2 id="startup">
<title>Automatic startup</title>
<orderedlist>
<listitem>
<para><emphasis>Red Hat:</emphasis></para>
<para>All init scripts are located in <filename>/etc/init.d/</filename>,
which are sym-linked to the correct runlevel
(<filename>/etc/rcX.d/</filename>). You can issue the command:</para>
<screen>
# chkconfig --add mobile-ip6
</screen>
<para>to enable MIPv6 at startup, or</para>
<screen>
# chkconfig --del mobile-ip6
</screen>
<para>to remove MIPv6 from startup.</para>
</listitem>
<listitem>
<para><emphasis>Debian:</emphasis></para>
<para>If you are so lucky to be running Debian, you can issue
the command:</para>
<screen>
# update-rc.d -n mobile-ip6 start 75 3 4 5 . stop 05 1 2 6 .
</screen>
<para>to set up all the necessary links.</para>
</listitem>
<listitem>
<para><emphasis>Slackware:</emphasis></para>
<para>Slackware users have all their startup/runlevel scripts in
<filename>/etc/rc.d</filename>. Since 'configure' doesn't check for
<quote>/etc/rc.d</quote>,
you can add <emphasis>INIT_SLACK="/etc/rc.d"</emphasis>, and then
INIT_SLACK to INITDIRS in 'configure' (search for INITDIR in
configure). Since you are running Slackware, you probably know
this already. The following command should then do the
trick:</para>
<screen>
# echo '/etc/rc.d/mobile-ip6 start' >> /etc/rc.d/rc.local
</screen>
<para>If you don't hack the Makefile, the
<filename>mobile-ip6</filename> script is installed at '/' (you
may then move it to /etc/rc.d/).</para>
</listitem>
</orderedlist>
</sect2>
</sect1>
<!-- ##################################################### -->
<sect1 id="testbed">
<title>Test bed</title>
<para>Now you should have a working MIPL patched kernel, installed
userlevel tools and enabled automatic startup at boot. If anything
went wrong, go through the above sections carefully.</para>
<!-- ################## -->
<sect2 id="testcase">
<title>Testcase</title>
<para>The addresses we are using in our test-bed are
site-local. You may as well use global addresses, but do
<emphasis>note that link local addresses won't work!</emphasis>
Our test-bed consist of four nodes; see figure
<link linkend="mipv6testbed">"Mobile IPv6 testbed"</link>.</para>
<orderedlist>
<listitem>
<para><emphasis>HA - Home Agent:</emphasis> The HA is located at the home
network with address <userinput>fec0:106:2700::2</userinput>,
with one wireless interface.</para>
</listitem>
<listitem>
<para><emphasis>MN - Mobile Node:</emphasis> When MN is on the
<quote>home network</quote>, it has address
<userinput>fec0:106:2700::4</userinput>. When MN travels to
another network, it generates a new <quote>care-of</quote> address.</para>
</listitem>
<listitem>
<para><emphasis>R - Router:</emphasis> This is the router from
the home network to the internet. It has one wireless interface with
address <userinput>fec0:106:2700::1</userinput> and a wired
interface with address <userinput>fec0:106:2300::2</userinput>.
</para>
</listitem>
<listitem>
<para><emphasis>AR - Access Router:</emphasis> The link
between AR and R is our <quote>internet</quote> - but in this
testcase only a cross-cable (can be any network). The AR has
two interfaces; the wired interface to R has address
<userinput>fec0:106:2300::1</userinput>, the wireless has
address <userinput>fec0:106:1100::1</userinput>.</para>
</listitem>
</orderedlist>
<mediaobject id="mipv6testbed">
<imageobject>
<imagedata fileref="images/mipv6-testbed.png" format="PNG"
width="550px" align="center" scalefit="1"/>
</imageobject>
<textobject>
<phrase>Mobile IPv6 testbed</phrase>
</textobject>
<caption>
<para>Mobile IPv6 testbed</para>
</caption>
</mediaobject>
</sect2>
<!-- ################## -->
<sect2 id="stepbystep">
<title>Step-by-step configuration</title>
<!-- ############ -->
<sect3 id="fullyipv6">
<title>Setting up a fully functional IPv6 network</title>
<para>Before we can start testing mobile IP, we need a fully
functional IPv6 network. All the nodes should be able to ping
each other. <emphasis>This is a crucial part.</emphasis> If, for
example, AR is not able to ping HA, then there will be no binding
update.</para>
<para>I will give a brief instruction to get our network up and
running using IPv6. For more info on setting up an IPv6 network,
you can read Peter Bieringer's excellent <ulink
url="http://ldp.linux.no/HOWTO/Linux+IPv6-HOWTO/">Linux IPv6
HOWTO</ulink>.</para>
<para>I've turned off encryption for simplicity - <emphasis>NOTE that you
should ALWAYS use encryption when dealing with wireless
networks!</emphasis></para>
<para><emphasis>Also note that the different wireless networks
have different ESSIDs!</emphasis></para>
<orderedlist>
<listitem>
<para><emphasis>MN:</emphasis> The Mobile Node has one wireless
interface. Forwarding should be turned off, but should accept
autoconf and ra's:</para>
<screen>
# iwconfig eth0 mode ad-hoc essid homenet enc off
# ifconfig eth0 inet6 add fec0:106:2700::4/64
# echo "0" > /proc/sys/net/ipv6/conf/eth0/forwarding
# echo "1" > /proc/sys/net/ipv6/conf/eth0/autoconf
# echo "1" > /proc/sys/net/ipv6/conf/eth0/accept_ra
# echo "1" > /proc/sys/net/ipv6/conf/eth0/accept_redirects
# /etc/init.d/mobile-ip6 start
</screen>
</listitem>
<listitem>
<para><emphasis>HA:</emphasis> The Home Agent has one
wireless interface. It should have forwarding turned on
because it uses normal routing to deliver packets captured
from a physical interface to the virtual tunnel
interface. <emphasis>Note: You must add a default route or else
HA will have problem contacting the MN on visited LAN's. One
possible solution is to use HA as the default router of the
home network.</emphasis></para>
<screen>
# iwconfig eth0 mode ad-hoc essid homenet enc off
# ifconfig eth0 inet6 add fec0:106:2700::2/64
# echo "1" > /proc/sys/net/ipv6/conf/eth0/forwarding
# echo "0" > /proc/sys/net/ipv6/conf/eth0/autoconf
# echo "0" > /proc/sys/net/ipv6/conf/eth0/accept_ra
# echo "0" > /proc/sys/net/ipv6/conf/eth0/accept_redirects
# ip route add ::/0 via fec0:106:2700::1
# /etc/init.d/mobile-ip6 start
</screen>
</listitem>
<listitem>
<para><emphasis>R:</emphasis> The (home) Router has two
interfaces; one wireless and one line. The Router must have
forwarding turned on. </para>
<screen>
# ifconfig eth0 inet6 add fec0:106:2300::2/64
# iwconfig eth1 mode ad-hoc essid homenet enc off
# ifconfig eth1 inet6 add fec0:106:2700::1/64
# echo "1" > /proc/sys/net/ipv6/conf/all/forwarding
# echo "0" > /proc/sys/net/ipv6/conf/all/autoconf
# echo "0" > /proc/sys/net/ipv6/conf/all/accept_ra
# echo "0" > /proc/sys/net/ipv6/conf/all/accept_redirects
# ip route add fec0:106:1100::/64 via fec0:106:2300::1
</screen>
</listitem>
<listitem>
<para><emphasis>AR:</emphasis> The Access Router (on a foreign
network) also has two interfaces; one wireless and one
line. Forwarding must be turned on.</para>
<screen>
# ifconfig eth0 inet6 add fec0:106:2300::1/64
# iwconfig eth1 mode ad-hoc essid visitnet enc off
# ifconfig eth1 inet6 add fec0:106:1100::1/64
# echo "1" > /proc/sys/net/ipv6/conf/all/forwarding
# echo "0" > /proc/sys/net/ipv6/conf/all/autoconf
# echo "0" > /proc/sys/net/ipv6/conf/all/accept_ra
# echo "0" > /proc/sys/net/ipv6/conf/all/accept_redirects
# ip route add fec0:106:2700::/64 via fec0:106:2300::2
</screen>
</listitem>
</orderedlist>
<para>Instead of modifying proc variables, you can use
<emphasis>sysctl</emphasis>.</para>
<para>Note: We are setting static routes on our test-bed. You
should now be able to ping all the hosts from every host.</para>
</sect3>
<!-- ############ -->
<sect3 id="confmipv6">
<title>Configuring Mobile IPv6</title>
<para>The last configuration is MIPv6 settings in
<filename>network-mip6.conf</filename>. In Debian/Slackware the
file is found under <filename>/etc/</filename>. (RedHat the file
is found under <filename>/etc/sysconfig/</filename>.) The file
should be pretty self-explanatory. </para>
<orderedlist>
<listitem>
<para><emphasis>HA:</emphasis> The HA config file should
contain these settings:</para>
<screen>
# cat /etc/network-mip6.conf
# Home Agent configuration file
FUNCTIONALITY=ha
DEBUGLEVEL=1
MIN_TUNNEL_NR=1
MAX_TUNNEL_NR=5
TUNNEL_SITELOCAL=yes
</screen>
</listitem>
<listitem>
<para><emphasis>MN:</emphasis> The MN config file should
look like this:</para>
<screen>
# cat /etc/network-mip6.conf
# Mobile Node configuration file
FUNCTIONALITY=mn
DEBUGLEVEL=1
TUNNEL_SITELOCAL=yes
MIN_TUNNEL_NR=1
MAX_TUNNEL_NR=3
HOMEDEV=mip6mnha1
HOMEADDRESS=fec0:106:2700::4/64 # MN's home adress
HOMEAGENT=fec0:106:2700::2/64 # HA's address
</screen>
</listitem>
<listitem>
<para>Next, start mobile-IP:</para>
<screen>
# /etc/init.d/mobile-ip6 start
Starting Mobile IPv6: OK
</screen>
</listitem>
</orderedlist>
<para>You can verify that it started by doing a
<userinput>ifconfig</userinput> on HA. If the tunnel(s) comes up,
<varname>ip6tnl1</varname>, mobile-ip6 is started:</para>
<screen>
# ifconfig
eth1 Link encap:Ethernet HWaddr 00:02:2D:2D:DE:79
inet6 addr: fec0:106:2700::2/64 Scope:Site
inet6 addr: fe80::202:2dff:fe2d:de79/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:618 errors:6 dropped:6 overruns:0 frame:6
TX packets:1485 errors:22 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:87914 (85.8 KiB) TX bytes:252596 (246.6 KiB)
Interrupt:3 Base address:0x100
ip6tnl1 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 <co id="tunnel1"/>
UP POINTOPOINT RUNNING NOARP MTU:1460 Metric:1
RX packets:6 errors:0 dropped:0 overruns:0 frame:0
TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:576 (576.0 b) TX bytes:624 (624.0 b)
ip6tnl2 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00 <co id="tunnel2"/>
UP RUNNING NOARP MTU:1460 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:0 (0.0 b)
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:8 errors:0 dropped:0 overruns:0 frame:0
TX packets:8 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:560 (560.0 b) TX bytes:560 (560.0 b)
</screen>
<calloutlist>
<callout arearefs="tunnel1">
<para>The tunnel is up and ready for connections.</para>
</callout>
<callout arearefs="tunnel2">
<para>Another tunnel ready.</para>
</callout>
</calloutlist>
<para>You will also see the mipv6 kernel modules are loaded (MN):</para>
<screen>
# lsmod
Module Size Used by Not tainted
mip6_mn 59888 0 (unused)
ipv6_tunnel 11448 1 [mip6_mn]
mip6_base 40728 0 [mip6_mn]
ipv6 179764 -1 [mip6_mn ipv6_tunnel mip6_base]
...
</screen>
</sect3>
<!-- ############ -->
<sect3 id="ARradvd">
<title>Configuring radvd on AR</title>
<para>When MN comes to a new network, it does a link-local address
configuration, going to the next phase if that succeeds. I'll let
<ulink
url="http://www.ietf.org/rfc/rfc2462.txt">[RFC2462]</ulink>
(IPv6 Stateless Address Autoconfiguration) describe the next
phase:</para>
<para>
<quote>The next phase of autoconfiguration involves obtaining a Router
Advertisement or determining that no routers are present. If routers
are present, they will send Router Advertisements that specify what
sort of autoconfiguration a host should do. If no routers are
present, stateful autoconfiguration should be invoked.</quote></para>
<para>
<quote>Routers send Router Advertisements periodically, but the delay
between successive advertisements will generally be longer than a
host performing autoconfiguration will want to wait. To
obtain an advertisement quickly, a host sends one or more Router
Solicitations to the all-routers multicast group.</quote> --- page 8</para>
<para>This is where we use
<ulink url="http://v6web.litech.org/radvd/">RADVD</ulink>.</para>
<para>Read <ulink
url="http://www.ietf.org/rfc/rfc2462.txt">[RFC2462]</ulink>
more details concerning IPv6 Stateless Address
Autoconfiguration.</para>
<para>We'll configure RADVD on AR's wireless interface. The
<filename>radvd.conf</filename> file should contain this:</para>
<screen>
# cat /etc/radvd.conf
interface eth1
{
AdvSendAdvert on;
AdvIntervalOpt on;
MinRtrAdvInterval 3;
MaxRtrAdvInterval 10;
AdvHomeAgentFlag off;
prefix fec0:106:1100::/64
{
AdvOnLink on;
AdvAutonomous on;
AdvRouterAddr on;
};
};
</screen>
<para>We then start it:</para>
<screen>
# /etc/init.d/radvd start
</screen>
<para>You should now be able to use <userinput>radvdump</userinput> to
see that the radvd messages really are being sent periodically:</para>
<screen>
# radvdump
Router advertisement from fe80::202:2dff:fe54:d1b2 (hoplimit 255)
Received by interface eth1
# Note: {Min,Max}RtrAdvInterval cannot be obtained with radvdump
AdvCurHopLimit: 64
AdvManagedFlag: off
AdvOtherConfigFlag: off
AdvHomeAgentFlag: off
AdvReachableTime: 0
AdvRetransTimer: 0
Prefix fec0:106:1100::/64
AdvValidLifetime: 2592000
AdvPreferredLifetime: 604800
AdvOnLink: on
AdvAutonomous: on
AdvRouterAddr: off
AdvSourceLLAddress: 00 02 2D 54 D1 B2
</screen>
<para><emphasis>Note! When using radvd on HA and enabling
<quote>autoconf</quote> (in proc), you will also get an
autogenerated IPv6 address on MN (which is superfluous) in
addition to your static address:</emphasis></para>
</sect3>
<!-- ############ -->
<sect3 id="radvdar">
<title>Configuring radvd on HA</title>
<para>
To enable the MN to know when it's home, HA should also be sending
out RAs. We should therefore enable RADVD on the HA as well. The
<filename>/etc/radvd.conf</filename> file should contain:
</para>
<screen>
# cat /etc/radvd.conf
interface eth0
{
AdvSendAdvert on;
MaxRtrAdvInterval 3;
MinRtrAdvInterval 1;
AdvIntervalOpt off;
AdvHomeAgentFlag on;
HomeAgentLifetime 10000;
HomeAgentPreference 20;
AdvHomeAgentInfo on;
prefix fec0:106:2700::2/64
{
AdvRouterAddr on;
AdvOnLink on;
AdvAutonomous on;
AdvPreferredLifetime 10000;
AdvValidLifetime 12000;
};
};
</screen>
<para>Also do a <userinput>radvdump</userinput> on HA to check
whether radvd messages are beeing sent:</para>
<screen>
# radvdump
Router advertisement from fe80::202:2dff:fe54:d11e (hoplimit 255)
Received by interface eth0
# Note: {Min,Max}RtrAdvInterval cannot be obtained with radvdump
AdvCurHopLimit: 64
AdvManagedFlag: off
AdvOtherConfigFlag: off
AdvHomeAgentFlag: on
AdvReachableTime: 0
AdvRetransTimer: 0
Prefix fec0:106:2700::2/64
AdvValidLifetime: 12000
AdvPreferredLifetime: 10000
AdvOnLink: on
AdvAutonomous: on
AdvRouterAddr: on
AdvSourceLLAddress: 00 02 2D 54 D1 1E
AdvHomeAgentInfo:
HomeAgentPreference: 20
HomeAgentLifetime: 1000
</screen>
<screen>
# ifconfig eth0
eth0 Link encap:Ethernet HWaddr 00:90:7D:F3:03:1A
inet6 addr: fec0:106:2700:0:290:7dff:fef3:31a/64 Scope:Site <co id="newaddress"/>
inet6 addr: fec0:106:2700::4/64 Scope:Site <co id="staticadr"/>
inet6 addr: fe80::290:7dff:fef3:31a/64 Scope:Link <co id="linkaddrs"/>
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:513 errors:89 dropped:89 overruns:0 frame:85
TX packets:140 errors:41 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:56084 (54.7 Kb) TX bytes:19212 (18.7 Kb)
Interrupt:3 Base address:0x100
</screen>
<calloutlist>
<callout arearefs="newaddress">
<para>A new (superfluous) autogenerated address. Since we are
setting <userinput>autoconf</userinput> in
<userinput>/proc/sys/net/ipv6/conf/eth0/autoconf</userinput>
to <userinput>1</userinput>, MN will generate a new adress
combined with HA's prefix and it's own MAC address. I do not
think is it possible to avoid having this address generated.</para>
</callout>
<callout arearefs="staticadr">
<para>Our original static IPv6 address</para>
</callout>
<callout arearefs="linkaddrs">
<para>The link-local address generated at boot.</para>
</callout>
</calloutlist>
</sect3>
</sect2>
</sect1>
<!-- ##################################################### -->
<sect1 id="dotest">
<title>Doing some tests</title>
<sect2 id="pretest">
<title>Pre-test</title>
<para>Do every configuration as shown above; it's especially important
to have a different ESSID on the home net and visited network. </para>
<para>When you start mobile-IPv6 on MN, you will see
multicasting router solicitations messages:</para>
<screen>
# tcpdump -i eth0 -vv ip6 or proto ipv6
...
13:32:54.681763 fe80::202:a5ff:fe6f:a08a > ff02::2: icmp6: router solicitation \
(src lladdr: 0:2:a5:6f:a0:8a) (len 16, hlim 255)
13:32:55.681763 fe80::202:a5ff:fe6f:a08a > ff02::2: icmp6: router solicitation \
(src lladdr: 0:2:a5:6f:a0:8a) (len 16, hlim 255)
13:32:57.681765 fe80::202:a5ff:fe6f:a08a > ff02::2: icmp6: router solicitation \
(src lladdr: 0:2:a5:6f:a0:8a) (len 16, hlim 255)
...
</screen>
</sect2>
<!-- ################## -->
<sect2 id="MovDet">
<title>Movement detection</title>
<para>Generic movement detection uses Neighbor Unreachability
Detection to detect when the default router is no longer
bi-directionally reachable, in which case the mobile node must
discover a new default router (usually on a new link).</para>
<para> To easily see whats going on, you should have one xterm
window for each of these commands: </para>
<screen>
# watch ifconfig eth0
# watch route -A inet6
# tcpdump -i eth0 -vv ip6 or proto ipv6
</screen>
<para>To <quote>travel</quote> to another net, you can issue the
command on MN:</para>
<screen>
# iwconfig eth1 essid visitnet
</screen>
<para>The MN is then on the other wireless network, and since it is
sending out <quote>router solicitation</quote> (multicast), our AR will
respond with it's prefix. MN will then configure itself with at new
IPv6 address with the received prefix and it's own MAC address. If
you type <command>ifconfig eth0</command> you will see the new IPv6
address:</para>
<screen>
# ifconfig eth0
eth0 Link encap:Ethernet HWaddr 00:90:7D:F3:03:1A
inet6 addr: fec0:106:1100:0:290:7dff:fef3:31a/64 Scope:Site <co id="newaddr"/>
inet6 addr: fec0:106:2700:0:290:7dff:fef3:31a/64 Scope:Site <co id="superadr"/>
inet6 addr: fec0:106:2700::4/64 Scope:Site <co id="oldaddr"/>
inet6 addr: fe80::290:7dff:fef3:31a/64 Scope:Link <co id="linkaddr"/>
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:854 errors:154 dropped:154 overruns:0 frame:148
TX packets:293 errors:58 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:96536 (94.2 Kb) TX bytes:44664 (43.6 Kb)
Interrupt:3 Base address:0x100
</screen>
<calloutlist>
<callout arearefs="newaddr">
<para>The new <quote>foreign</quote> address, generated by
combining AR's prefix and MAC-address</para>
</callout>
<callout arearefs="superadr">
<para>The superfluous home network address (because of HA
radvd messages and MN autoconf set to
<quote>true</quote>).</para>
</callout>
<callout arearefs="oldaddr">
<para>The <quote>original</quote> (home) address</para>
</callout>
<callout arearefs="linkaddr">
<para>The link-local address generated at boot</para>
</callout>
</calloutlist>
<para>Almost at the same time, the MN will perform a binding update
to HA. In your tcpdump window, you will see several packets
destined to HA. To verify that the binding update has been sent and
acknowledged from MN:</para>
<screen>
# mipdiag -s
Mobile IPv6 Statistics
NEncapsulations : 0
NDecapsulations : 0
NBindUpdatesRcvd : 0
NBindAcksRcvd : 1 <co id="back"/>
NBindNAcksRcvd : 0
NBindRqsRcvd : 0
NBindUpdatesSent : 1 <co id="bupdate"/>
NBindAcksSent : 0
NBindNAcksSent : 0
NBindRqsSent : 0
NBindUpdatesDropAuth : 0
NBindUpdatesDropInvalid : 0
NBindUpdatesDropMisc : 0
NBindAcksDropAuth : 0
NBindAcksDropInvalid : 0
NBindAcksDropMisc : 0
NBindRqsDropAuth : 0
NBindRqsDropInvalid : 0
NBindRqsDropMisc : 0
</screen>
<calloutlist>
<callout arearefs="back">
<para>One binding ACK received.</para>
</callout>
<callout arearefs="bupdate">
<para>One binding UPDATE sent.</para>
</callout>
</calloutlist>
<para>You can also verify the binding with the following command
(on MN):</para>
<screen>
# mipdiag -l
Mobile IPv6 Binding update list
Recipient CN: fec0:106:2700::2
BINDING home address: fec0:106:2700::4 care-of address: fec0:106:1100:0:290:7dff:fef3:31a
expires: 936 sequence: 0 state: 1
delay: 3 max delay 32 callback time: 736
</screen>
<para>You can also verify it on HA with the statistics option
(-s) and with the <quote>binding cache</quote> (-c) option:</para>
<screen>
# mipdiag -c
Mobile IPv6 Binding cache
Home Address Care-of Address Lifetime Type
fec0:106:2700::4 fec0:106:1100:0:290:7dff:fef3:31a 971 2
</screen>
</sect2>
<!-- ################## -->
<sect2 id="ping6">
<title>ping6</title>
<para>From the MN, you can try to ping AR's eth1
(fec0:106:1100::1):</para>
<screen>
# ping6 fec0:106:1100::1
PING fec0:106:1100::1(fec0:106:1100::1) from fec0:106:2700::4 : 56 data bytes
64 bytes from fec0:106:1100::1: icmp_seq=1 ttl=62 time=8.01 ms
64 bytes from fec0:106:1100::1: icmp_seq=2 ttl=62 time=8.02 ms
...
</screen>
<para>By using tcpdump, you can see how the packets travel:</para>
<screen>
12:13:51.789688 fec0:106:1100:0:202:a5ff:fe6f:a08a > fec0:106:2700::2: \ <co id="mntoha"/>
fec0:106:2700::4 > fec0:106:1100::1: icmp6: echo request \ <co id="hatocr"/>
(len 64, hlim 64) (len 104, hlim 255)
12:13:51.797675 fec0:106:2700::2 > fec0:106:1100:0:202:a5ff:fe6f:a08a: \ <co id="artomn"/>
fec0:106:1100::1 > fec0:106:2700::4: icmp6: echo reply \
(len 64, hlim 62) (len 104, hlim 253)
</screen>
<calloutlist>
<callout arearefs="mntoha">
<para>The packet first goes from MN to the HA using MN new
IPv6 address.</para>
</callout>
<callout arearefs="hatocr">
<para>Then from HA to AR.</para>
</callout>
<callout arearefs="artomn">
<para>The AR then responds to HA and tunnels the packets to
MN.</para>
</callout>
</calloutlist>
<para>You can now see the statistics have been updated (on MN):</para>
<screen>
# mipdiag -s
Mobile IPv6 Statistics
NEncapsulations : 56
NDecapsulations : 25
...
</screen>
</sect2>
<!-- ################## -->
<sect2 id="routeTable">
<title>Kernel IP routing table</title>
<para>One interesting thing MIPv6 does is change the default route to
a tunnel. The new default route becomes:</para>
<screen>
# route -A inet6
Kernel IPv6 routing table
Destination Next Hop Flags Metric Ref Use Iface
::/0 :: UD 64 0 0 ip6tnl1
....
</screen>
<para>If it doesn't add a default route, you may add it manually:</para>
<screen>
# ip route ::/0 via dev ip6tnl
</screen>
</sect2>
<!-- ################## -->
<sect2 id="movement">
<title>Travelling through several foregin LAN's</title>
<para>To travel to several visited networks, is no different than
travel to <emphasis>one</emphasis> network. The only thing you
must have in mind is that you will generate a new address for each
visited network.
</para>
<mediaobject id="LANvisits">
<imageobject>
<imagedata fileref="images/lanvisits.png" format="PNG"
width="550px" align="center" scalefit="1"/>
</imageobject>
<textobject>
<phrase></phrase>
</textobject>
<caption>
<para>MN travelling through severeal different LANs.</para>
</caption>
</mediaobject>
<orderedlist>
<listitem>
<para>MN first visits 'visitnet', as we have been through above.</para>
</listitem>
<listitem>
<para>MN is then travelling from 'visitnet' to
'visitnet2'.</para>
</listitem>
<listitem>
<para>When at 'visitnet2', MN generates a new IPv6 address and
do a new binding update to HA.</para>
</listitem>
<listitem>
<para>MN then travels back home. (Se next section.)</para>
</listitem>
</orderedlist>
<para>The AR at <quote>visitnet2</quote>, is configured exactly
as the other AR (at <quote>visitnet</quote>), except using address
<userinput>fec0:106:1000::/64</userinput> instead of
<userinput>fec0:106:1100::/64</userinput>.</para>
<para>To make the mobile node travel from 'visitnet' to
'visitnet2', issue the command (on MN):</para>
<screen>
# iwconfig eth0 essid visitnet2
</screen>
<para>You will then see the MN configures itself to the new network:</para>
<screen>
# ifconfig eth0
eth1 Link encap:Ethernet HWaddr 00:90:7D:F3:03:1A
inet6 addr: fec0:106:1000:0:290:7dff:fef3:31a/64 Scope:Site <co id="net2"/>
inet6 addr: fec0:106:1100:0:290:7dff:fef3:31a/64 Scope:Site
inet6 addr: fec0:106:2700:0:290:7dff:fef3:31a/64 Scope:Site
inet6 addr: fec0:106:2700::4/64 Scope:Site
inet6 addr: fe80::290:7dff:fef3:31a/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1073 errors:212 dropped:212 overruns:0 frame:204
TX packets:371 errors:72 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:120340 (117.5 Kb) TX bytes:56912 (55.5 Kb)
Interrupt:3 Base address:0x100
</screen>
<calloutlist>
<callout arearefs="net2">
<para>The new autoconfigured address at 'visitnet2'.</para>
</callout>
</calloutlist>
<para><emphasis>Note! You may have to restart mobile-ipv6 on MN
when coming to a new network!</emphasis></para>
<screen>
# /etc/init.d/mobile-ip6 restart
Stopping Mobile IPv6: OK
Starting Mobile IPv6: OK
</screen>
<para>The MN will then perform a new binding update to HA. Notice
the new <quote>care-of address</quote>:</para>
<screen>
# mipdiag -l
Mobile IPv6 Binding update list
Recipient CN: fec0:106:2700::2
BINDING home address: fec0:106:2700::4 care-of address: fec0:106:1000:0:290:7dff:fef3:31a
expires: 973 sequence: 14 state: 1
delay: 3 max delay 32 callback time: 773
</screen>
<para>You can also see the <quote>binding cache</quote> on HA has
been updated:</para>
<screen>
# mipdiag -c
Mobile IPv6 Binding cache
Home Address Care-of Address Lifetime Type
fec0:106:2700::4 fec0:106:1000:0:290:7dff:fef3:31a 943 2
</screen>
</sect2>
<!-- ################## -->
<sect2 id="home">
<title>Returning home</title>
<para>To make the MN return home, you can just issue the
command:</para>
<screen>
# iwconfig eth0 essid homenet
</screen>
<para>The MN will know it is back home, since HA is sending out
radvd messages with the HA-bit set (AdvHomeAgentFlag), see <xref
linkend="radvdar"/></para>
<para>You can see the MN <quote>is back home</quote>, since the
binding cache information at HA is flushed (empty):</para>
<screen>
Mobile IPv6 Binding cache
Home Address Care-of Address Lifetime Type
</screen>
</sect2>
<!-- ################## -->
<sect2 id="realLife">
<title>Real life testing - smooth handover</title>
<para>To really get the feel on how mobile IP works, fire up GnomeMeeting
(See the figure GnomeMeeting and start a netmeeting. Note! You must use
the latest GnomeMeeting to get support for IPv6! Then do a <quote>travel</quote>
and you can see an almost smooth handover.</para>
<mediaobject id="gnomemeeting">
<imageobject>
<imagedata fileref="images/gnomemeeting1.png" format="PNG"
width="250px" align="center" scalefit="1"/>
</imageobject>
<textobject>
<phrase>GnomeMeeting</phrase>
</textobject>
<caption>
<para>Using GnomeMeeting with IPv6 to test roaming between two
wireless networks</para>
</caption>
</mediaobject>
</sect2>
</sect1>
<!-- ##################################################### -->
<sect1 id="faq">
<title>FAQ</title>
<orderedlist>
<listitem>
<para><emphasis>Q: Why do we have to create the
<filename>/dev/mipv6_dev</filename> entry?</emphasis></para>
<para>A: The dev file is mainly so that the userspace tool,
mipdiag, can make modifications to the kernel parameters using
ioctl calls through the device file. <command>mknod</command> creates the special
device file with paramters recognizable by the mobile-ip6
module.</para>
</listitem>
<listitem>
<para><emphasis>Q: Is there any support for kernel 2.6.x?</emphasis></para>
<para>A: Here is the<ulink
url="http://www.mobile-ipv6.org/pipermail/mipl/2003-December/001871.html">
answer from Henrik Petander</ulink> on the MIPL
mailinglist:</para>
<para><quote>Here is a short overview of the status of MIPL for
2.6 kernel series:</quote></para>
<para><quote>We have finished the kernel infrastructure for
Mobile IPv6 in cooperation with the USAGI project. The
infrastructure does route optimization, tunneling and policy
routing.</quote></para>
<para><quote>We are now working on the userspace daemon which
handles the MIPv6 signaling and controls the operation of the
kernel part. The userspace part is also progressing
nicely. However, the protocol logic is still missing, so there
isn't really anything for users to test yet. We should have a
well working and tested prototype ready and by the end of
March.</quote></para>
</listitem>
<listitem>
<para><emphasis>Q: Does MIPL support
IPSec?</emphasis></para>
<para>A: There is no support IPSec on 2.4.x. MIPL for 2.6 series will
have IPSec support from the start. You may use a third-party IPSec
implementation.</para>
</listitem>
<listitem>
<para><emphasis>Q: How can I control the type of routing used for
communication between the MN and a CN (through HA tunnel or by
direct communication using binding update/acks)?</emphasis></para>
<para>A: You can control this through:</para>
<para>
<userinput>/proc/sys/conf/net/ipv6/mobility/accept_return_routability</userinput>
</para>
<para>If you do not want to use return routability and route optimization,
set it to 0 with:</para>
<para>
<userinput># echo 0 >
/proc/sys/..../accept_return_routability</userinput>
</para>
<para> Then MN will communicate with CNs only through the
home tunnel.</para>
</listitem>
<listitem>
<para><emphasis>Q: Can different wireless networks
have different ESSIDs/WEP keys?</emphasis></para>
<para>A: Yes, but you must change this upon arrival to the new
network. MIPv6 from MIPL can't do this automatically.</para>
</listitem>
<listitem>
<para><emphasis>Q: If MN has travelled through several visited
LAN, and then returning home; the interface still has all the
autogenerated IPv6 addresses from all the visited networks! Is
there any way to <quote>flush/delete</quote> these
addresses?</emphasis></para>
<para>A: No, I do not know of any automatic way these adresses
can be removed, but you can delete them manually:</para>
<para><userinput>
# ifconfig eth0 inet6 del &lt;ipv6-address>
</userinput></para>
</listitem>
<listitem>
<para><emphasis>Q: Host B has two interfaces with two
different subnets assigned. When I ping B from host A, it does
not answer! Why not? Host A knows where host B
(subnets) are!</emphasis></para>
<para>A: The host B doesn't know where host A is (B doesn't
know where A's net is), so you must add a route
entry:</para>
<para><userinput>
# ip route add fec0:106:2700::/64 via fec0:106:2300::1
</userinput></para>
<para>or</para>
<para><userinput>
# route -A inet6 add fec0:106:2700::/64 gw fec0:106:2300::1 dev eth0
</userinput></para>
</listitem>
<listitem>
<para><emphasis>Q: How do I set a default gateway in
IPv6?</emphasis></para>
<para>A: You do that using the traditional <quote>route</quote>:</para>
<para><userinput>
# route -A inet6 add default gw &lt;ipv6-host>
</userinput></para>
<para>or the newer <quote>ip</quote> command:</para>
<para><userinput>
# ip route ::/0 via &lt;ipv6-host>
</userinput></para>
</listitem>
<listitem>
<para><emphasis>Q: Why does the host send a multicast
address rather than an anycast address, requesting for router
solicitation?</emphasis></para>
<para>A: Because the host wants an answer from every router, not from just any
router. The idea is to be able to get all parameters and to choose
the <quote>best</quote> default router.</para>
</listitem>
<listitem>
<para><emphasis>Q: Why doesn't MN notice that it has
moved?</emphasis></para>
<para>A: It thinks that it's previous router is still reachable. This may
result from very large lifetimes in router advertisements. Check the
configuration of the program sending router advertisements in the
router. If the program supports router advertisement intervals, you
can use this to help MN in movement detection by setting the use of
interval to <option>on</option>. See <command>man radvd.conf</command> for
details.</para>
</listitem>
</orderedlist>
</sect1>
<!-- ##################################################### -->
<sect1 id="resources">
<title>Useful Resources</title>
<para>
<orderedlist>
<listitem>
<para>Mobile IPv6 for Linux <ulink
url="http://www.mipl.mediapoli.com/">
http://www.mipl.mediapoli.com/</ulink></para>
</listitem>
<listitem>
<para>Mobile IP Working Group (IETF) <ulink
url="http://www.ietf.org/html.charters/mobileip-charter.html">
http://www.ietf.org/html.charters/mobileip-charter.html </ulink></para>
</listitem>
<listitem>
<para>Mobile IPv6 draft <ulink
url="http://www.ietf.org/internet-drafts/draft-ietf-mobileip-ipv6-24.txt">
http://www.ietf.org/internet-drafts/draft-ietf-mobileip-ipv6-24.txt</ulink>
</para>
</listitem>
<listitem>
<para>IPv6 Working Group (IETF) <ulink
url="http://www.ietf.org/html.charters/ipv6-charter.html">
http://www.ietf.org/html.charters/ipv6-charter.html </ulink></para>
</listitem>
<listitem>
<para>RFC2460 Internet Protocol, Version 6 (IPv6) Specification
<ulink url="http://www.ietf.org/rfc/rfc2460.txt">
http://www.ietf.org/rfc/rfc2460.txt </ulink></para>
</listitem>
<listitem>
<para>RFC2461 Neighbor Discovery for IP Version 6 (IPv6) <ulink
url="http://www.ietf.org/rfc/rfc2461.txt">
http://www.ietf.org/rfc/rfc2461.txt </ulink></para>
</listitem>
<listitem>
<para>RFC2462 IPv6 Stateless Address Autoconfiguration <ulink
url="http://www.ietf.org/rfc/rfc2462.txt">
http://www.ietf.org/rfc/rfc2462.txt </ulink></para>
</listitem>
<listitem>
<para>Peter Bieringer's Linux IPv6 HOWTO (en) <ulink
url="http://ldp.linux.no/HOWTO/Linux+IPv6-HOWTO/">
http://ldp.linux.no/HOWTO/Linux+IPv6-HOWTO/ </ulink></para>
</listitem>
<listitem>
<para>Current Status of IPv6 Support for Networking Applications
<ulink url="http://www.deepspace6.net/docs/ipv6_status_page_apps.html">
http://www.deepspace6.net/docs/ipv6_status_page_apps.html</ulink></para>
</listitem>
<listitem>
<para>Linux Kernel HOWTO <ulink
url="http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/html_single/Kernel-HOWTO.html">
http://www.ibiblio.org/pub/Linux/docs/HOWTO/other-formats/html_single/Kernel-HOWTO.html
</ulink></para>
</listitem>
</orderedlist>
</para>
</sect1>
<!-- ##################################################### -->
<sect1 id="copyack">
<title>Copyright, acknowledgments and miscellaneous</title>
<!-- ################## -->
<sect2 id="copyright">
<title>Copyright and License</title>
<para> Copyright (c) 2003, 2004 Lars Strand.</para>
<para>
Permission is granted to copy, distribute and/or modify this
document under the terms of the <ulink
url="http://www.gnu.org/licenses/fdl.html">GNU Free
Documentation License</ulink>, Version 1.2 or any later version
published by the Free Software Foundation; with no Invariant
Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy
of the license is included in the section entitled "GNU Free
Documentation License".
</para>
</sect2>
<!-- ################## -->
<sect2 id="produced">
<title>How this document was produced</title>
<para>This document was originally written in LaTeX using
Emacs. HTML version created with latex2html. Later it was
converted to DocBook XML.</para>
<para>An up-to-date version of this document can be found at:</para>
<para> HTML: <ulink url="http://www.tldp.org/HOWTO/Mobile-IPv6-HOWTO/">
http://www.tldp.org/HOWTO/Mobile-IPv6-HOWTO/</ulink> </para>
</sect2>
<!-- ################## -->
<sect2 id="feedback">
<title>Feedback</title>
<para>Suggestions, corrections, additions wanted. Contributors
wanted and acknowledged. Flames not wanted.</para>
<para>I can always be reached at <email>lars at unik
no</email></para>
<para>Homepage: <ulink url="http://www.gnist.org/~lars">
http://www.gnist.org/~lars</ulink></para>
</sect2>
<!-- ################## -->
<sect2 id="ack">
<title>Acknowledgments</title>
<para>This document was produced as a part of Interoperable
Networks for Secure Communications <ulink
url="http://insc.nodeca.mil.no/">(INSC task 6)</ulink></para>
<para>Thanks to Andreas Hafslund (andreha [at] unik.no) for
initial support. Also thanks to UniK (University Graduate Center)
<ulink url="http://www.unik.no">http://www.unik.no</ulink> and FFI
(Norwegian Defence Research Establishment) <ulink
url="http://www.ffi.mil.no">http://www.ffi.mil.no</ulink> for
hardware support.</para>
<para>Thanks also to the other HOWTO authors whose works I have
referenced: </para>
<para><emphasis>Linux IPv6 HOWTO (en)</emphasis> by Peter
Bieringer</para>
</sect2>
</sect1>
<!-- ################## -->
<appendix id="gfdl">
<title>GNU Free Documentation License</title>
<subtitle>Version 1.2, November 2002</subtitle>
<blockquote id="fsf-copyright">
<para>Copyright (C) 2000,2001,2002 Free Software Foundation, Inc.
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.</para>
</blockquote>
<section id="gfdl-0"><title>PREAMBLE</title>
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<para>We have designed this License in order to use it for manuals for
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<section id="gfdl-1"><title>APPLICABILITY AND DEFINITIONS</title>
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<section id="gfdl-2"><title>VERBATIM COPYING</title>
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<section id="gfdl-4"><title>MODIFICATIONS</title>
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<orderedlist id="gfdl-modif-cond" numeration="upperalpha">
<listitem><simpara>Use in the Title Page (and on the covers, if any) a
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<section id="gfdl-5"><title>COMBINING DOCUMENTS</title>
<para>You may combine the Document with other documents released under
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<section id="gfdl-6"><title>COLLECTIONS OF DOCUMENTS</title>
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<section id="gfdl-7"><title>AGGREGATION WITH INDEPENDENT WORKS</title>
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<section id="gfdl-8"><title>TRANSLATION</title>
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<section id="gfdl-10"><title>FUTURE REVISIONS OF THIS LICENSE</title>
<para>The Free Software Foundation may publish new, revised versions of
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<section id="gfdl-addendum"><title>ADDENDUM: How to use this License for
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<para>To use this License in a document you have written, include a copy
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<blockquote id="copyright-sample"><para>
Copyright (c) YEAR YOUR NAME.
Permission is granted to copy, distribute and/or modify this document
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<blockquote id="inv-cover-sample"><para>
with the Invariant Sections being LIST THEIR TITLES, with the
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<para>If you have Invariant Sections without Cover Texts, or some other
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<para>If your document contains nontrivial examples of program code, we
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their use in free software.</para>
</section>
</appendix>
</article>
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