Mobile IP
순천향대학교 정보기술공학부
이상정
oIP 특론
2003-1-V
References
T
utorial: Mobile IP
http://www.computer.org/internet/v2n1/perkins.htm?SMSESSIO
N=NO
Mobile IP
http://www.acm.org/crossroads/xrds7-2/mobileip.html
How Mobile IP Works1.ppt
http://www.mnlab.cs.depaul.edu/seminar/spr2002/MobileIP
.pdf
mobile IP and TCP
http://distcomp.ethz.ch/lectures/mobicomp/lecture/8/Chapte
r8MobileIPandTCP4Slides.pdf
순천향대학교 정보기술공학부 이상정 2
oIP 특론
2003-1-V
Motivation for the Mobile IP design
1. Amobile node has to change its IP address
whenever it changes its point of attachment,
so that packets destined to the node are
routed correctly
2. o
T maintain existing TCP connections, the
mobile node has to keep its IP address the
same.
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oIP 특론
2003-1-V
Requirements to Mobile IP (RFC 2002)
Compatibility
• support of the same layer 2 protocols as IP
• no changes to current end-systems and routers required
• mobile end-systems can communicate with fixed systems
T
ransparency
• mobile end-systems keep their IP address
• continuation of communication after interruption of link possible
• point of connection to the fixed network can be changed
Efficiency and scalability
• only little additional messages to the mobile system required
(connection typically via a low bandwidth radio link)
• world-wide support of a large number of mobile systems
Security
• authentication of all registration messages
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oIP 특론
2003-1-V
erminology
T
Mobile Node (MN)
• system (node) that can change the point of connection to the
network without changing its IP address
HomeAgent (HA)
• system in the home network of the MN, typically a router
• registers the location of the MN, tunnels IP datagrams to the COA
ForeignAgent (F A)
• system in the current foreign network of the MN, typically a router
• typically the default router for the MN
Care-ofAddress (COA)
• address of the current tunnel end-point for the MN (at FAor MN)
• actual location of the MN from an IP point of view
• can be chosen, e.g., via DHCP
Correspondent Node (CN)
순천향대학교 정보기술공학부 이상정 5
oIP 특론
2003-1-V
순천향대학교 정보기술공학부 이상정 6
oIP 특론
2003-1-V
순천향대학교 정보기술공학부 이상정 7
oIP 특론
2003-1-V
순천향대학교 정보기술공학부 이상정 8
oIP 특론
2003-1-V
Mobility Binding
The home agent maintains the mobility binding
in a mobility binding table
순천향대학교 정보기술공학부 이상정 9
oIP 특론
2003-1-V
Mobility Binding
The foreign agent maintains a visitor list
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oIP 특론
2003-1-V
Agent Discovery
HAand F
Aperiodically send Advertisement
messages into their
MN listens to these messages and detects, if it
is in the home or a foreign network
• If MN does not wish to wait for the periodic
advertisement, it can send out Agent Solicitation
messages that will be responded by HAor FS
MN reads a COAfrom the F
Aadvertisement
messages
순천향대학교 정보기술공학부 이상정 1
oIP 특론
2003-1-V
Registration
MN signals COA to the HA via the FA, HA
acknowledges via FA to MN
• these actions have to be secured by authentication
순천향대학교 정보기술공학부 이상정 12
oIP 특론
2003-1-V
IP-in-IP Encapsulation
Mandatory in
RFC 2003
Tunneling
between HA and
COA
순천향대학교 정보기술공학부 이상정 13
oIP 특론
2003-1-V
IP-in-IP Encapsulation
순천향대학교 정보기술공학부 이상정 14
oIP 특론
2003-1-V
Triangular Routing
Sender sends all
packets via HA to MN
Higher latency and
network load
순천향대학교 정보기술공학부 이상정 15
oIP 특론
2003-1-V
Change of FA
Packets on-the-fly during the change can be
lost
New FA informs old FA to avoid packet loss,
old FA now forwards
Remaining packets to new FA
This information also enables the old FA to
release resources for the MN
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oIP 특론
2003-1-V
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oIP 특론
2003-1-V
Data transfer from the mobile system
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oIP 특론
2003-1-V
Reverse tunneling (RFC 2344)
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oIP 특론
2003-1-V
Mobile IPv6
Mobility support in IPv6 solves many of the
problems of basic Mobile IP
Some advantages of Mobile IPv6 over Mobile
IPv4
• Route Optimization is built as a fundamental part of
Mobile IPv6
• ForeignAgents are not needed in Mobile IPv6. The
enhanced features of IPv6 like Neighbour Discovery
andAddressAutoconfiguration enable mobile nodes to
function in any location without the services of any
special router in that location.
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