Mobile IP
Dr.Xinbing Wang
Institute of Wireless Communication Technology
Shanghai Jiaotong University
1Introduction
This document describes the software and procedures to t up and u mobile IPv6 for Linux.
1.1What is Mobile IP?
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.IPv6packets addresd to a mobile node’s home address are transparently routed to its care-of address.The protocol enables IPv6 nodes to cache the binding of a mobile node’s home address with its care-of address, and to then nd any packets destined for the mobile node directly to it at this care-of address.
1.2Why Mobile IP?
Without specific support for mobility in IPv6,packets destined to a mobile node would not be able to reach it while the mobile node is away from its home link. 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 IPv6is 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.
1.3How does it work?
As picture1:网络培训中心
1.The Mobile Node(MN)travels to a foreign network and gets a new care-of-
address.
Figure1:Mobile Ip
2.The MN performs a binding update to its Home Agent(HA)(the new care-of-
address gets registered at HA).HA nds a binding acknowledgement to MN.
3.A Corresponding Node(CN)wants to contact the MN.The HA intercepts
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packets destined to the MN.
4.The HA then tunnels all packets to the MN from the CN using MN’s care-of-
address.
5.When the MN answers the CN,it may u its current care-of-address(and
perform a binding to the CN)and communicate with the CN directly(route optimization)or it can tunnel all its packets through the HA.
1.4IPv6
IP version6(IPv6)is a new version of the Internet Protocol,designed as the successor to IP version4(IPv4).The changes from IPv4to IPv6fall primarily into the following categories:
1.Expanded addressing capabilities
2.Header format simplification
3.Improved support for extensions and options面点的100种做法
4.Flow labeling capability
5.Authentication and privacy capabilities
Figure2:Mobile IPv6testbed
For more information on IPv6in general,visit the IETF’s IPv6Working Group.
2Test bed
Now you should have a working MIPv6patched kernel and installed urlevel tools. If anything went wrong,go through the above ctions carefully.
2.1Testca
The address we are using in our test-bed are global.Our test-bed consist of four nodes,efigure2.
1.HA-Home Agent:The HA is located at the home network.It has one wireless
interface with address200X:5c0:8d03:1::1(Note:X is your testbed Group
ID,we have3group there in the labroom.And MN,AR,CN should obey this rule too.)and a wired interface with address200X:5c0:8d03:2::1.
2.MN-Mobile Node:When MN is on the”home network”,it has address
蚵仔煎200X:5c0:8d03:1::2.When MN travels to another network,it generates a new”care-of”address.
3.AR-Access Router:The link between AR and R is our”internet”(may be a
cross-cable).The AR has two interfaces;the wired interface to R has address 200X:5c0:8d03:2::2,the wireless has address200X:5c0:8d03:3::1.
4-Corresponding Node:nding messages to MN,with a wired address
不可多得200X:5c0:8d03:2::3.
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2.2Setting up a fully functional IPv6network
Note:all the nodes should be able to ping each other,and the different wireless networks have different ESSIDs.
For each of the laptops,open a terminal and type the following command to become root(super administrator).
insmod/lib/modules/2.6.16−001/kernel/drivers/net/wireless/rt61.ko
ifconfig ip6tnl0updnf图标
iwconfig ra0mode ad−hoc essid homenet
ifconfig ra0inet6add200X:5c0:8d03:1::2/64
echo”0”>/proc/sys/net/ipv6/conf/ra0/forwarding
echo”1”>/proc/sys/net/ipv6/conf/ra0/accept
echo”1”>/proc/sys/net/ipv6/conf/ra0/accept
echo”0”>/proc/sys/net/ipv6/conf/all/forwarding
echo”1”>/proc/sys/net/ipv6/conf/all/accept
echo”1”>/proc/sys/net/ipv6/conf/all/accept
2.HA:It should have forwarding turned on becau it us normal routing to de-
liver packets captured from a physical interface to the virtual tunnel interface.
iwconfig ra0mode ad−hoc essid homenet
ifconfig ra0inet6add200X:5c0:8d03:1::1/64
echo1>/proc/sys/net/ipv6/conf/ra0/forwarding
echo0>/proc/sys/net/ipv6/conf/ra0/accept
echo0>/proc/sys/net/ipv6/conf/ra0/accept
echo1>/proc/sys/net/ipv6/conf/all/forwarding
echo0>/proc/sys/net/ipv6/conf/all/accept
echo0>/proc/sys/net/ipv6/conf/all/accept
ip route add200X:5c0:8d03:3::/64via200X:5c0:8d03:2::2
3.AR:The Access Router(on a foreign network)also has two interfaces;one
wireless and one line.Forwarding must be turned on.
iwconfig ra0mode ad−hoc essid visitnet
ipad关机ifconfig ra0inet6add200X:5c0:8d03:3::1/64
echo1>/proc/sys/net/ipv6/conf/all/forwarding
echo0>/proc/sys/net/ipv6/conf/all/accept
echo0>/proc/sys/net/ipv6/conf/all/accept
ip route add200X:5c0:8d03:1::/64via200X:5c0:8d03:2::1
4:The source of the video stream nding to the MN.
ip route add200X:5c0:8d03:1::/64via200X:5c0:8d03:2::1
If you want to test if two nodes are connected,u the following command:
ping6200X:5c0:8d03:3::1
2.3Configuring Mobile IPv6
When you issue make install,neither init script nor configurationfile is installed. Example configurationfiles are found under the extra/directory under the source code.
HA:The HA configfile should contain the ttings:
#filename:/f
#If t to>0,will not detach from tty
#List of interfaces where we rve as Home Agent UMnHaIPc disabled;
MN:The MN configfile should look like this: #filename:/f
#If t to>0,will not detach from tty
MnDiscardHaParamProb enabled;
MnRouterProbes1;
HomeAgentAddress200X:5c0:8d03:1::1;
}
interface ra0
AdvSendAdvert on;
MaxRtrAdvInterval10;
{
AdvAutonomous on;
