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Mobile IP v6
“Stay connected.”
Guide : Mr. Murali Mohan
By : V.S.Shailesh (125/2002)
19 September 2018
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Ahead….
Current Scenario
Need for Mobile IP
How it works
What’s new in MIPv6
Conclusion
19 September 2018
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3. Trends in the wireless world
Mobile subscribers exceeded 1.2 Billion in 2004
Crashing prices of laptops in 2005
The merger between the mobile world and the Internet
Peer to peer applications on the rise
Heterogeneous access technologies
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Communication with IP
IP addresses enable routers to send packets to the correct network (not host)
Each IP address has network part and host part
By logically ANDing an IP address with a subnet mask, we get the network address
This keeps host specific information out of routers
DHCP is used to get packets to end hosts in networks
This whole procedure assumes that the end host is “fixed”
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Need for Mobile IP
IP assumes end hosts are in fixed physical locations
What if a user wants to roam between networks?
Mobile users want transparent roaming
Why can’t mobile users change IP when running an application?
Historical assumptions about “fixed” hosts has led to most protocols disallowing the changing of IP during a transaction
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Scenario
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MOBILE IP
Enables hosts to stay connected to the Internet regardless of their location
No modification of applications
Maintain connections while moving between subnets
Requires no changes to software of “fixed” hosts/routers
Requires no modifications to IP addresses or IP address format
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Where does it go ?
Network Applications
and Protocols
Telnet, FTP, HTTP, etc.
Mobility is seamless
to these.
TCP
UDP
TCP/IP
Protocol
STACK
Mobile IP
Ethernet
Token Ring
PPP
WLAN
802.11b
Bluetooth
The link layer can be anything.
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Terminology
Mobile Node (MN)
Correspondent Node (CN)
Home Agent (HA)
Foreign Agent (FA)
Home Address
Care of Address (CoA)
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Mobile IP strategy
Use two IP addresses per mobile host
One permanent address (called Home Address ) used for identification
Another IP address (called CoA) which changes constantly and is used for routing
The binding (association) between these two IP addresses is kept at the home agent (HA)
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Example
You are on a tour
You are the Mobile Node (MN)
Your mother is the Home Agent
Your hotel manager is the Foreign Agent
Your friend Jack who sends you letters is the Correspondent Node
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Step-1
When a MN moves to a new location, a foreign agent should be broadcasting advertisements on the subnet
The MN will be able to receive this broadcast message and will learn the IP address of the foreign agent
This will be the care-of-address(CoA) of the MN
In IPv6, the FA is absent and so the MN gets its own IP via DHCP (called collocated CoA)
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Step-2
Registration Request
Type
Flags
Lifetime
Home address HA
REQ
Home agent FA
Care-of-address
REQ
Identification M
Extensions
Registration Request Format
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Step-3
Registration Reply HA
RPL FA
Type
Code
Lifetime
Home address
RPL
Home agent M
Code:
Indicates the result of registration Some code values:
0 registration accepted
70 poorly formed request
131 mobile node failed authentication
Identification
Extensions
Registration Reply Format
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Binding
Registration updates binding. A binding consists of mobile hosts address and the care-of address
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Binding Tables
Mobility Binding Table
Maintained on Home Agent of MN
Maps MN’s home address with its current CoA
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Binding Tables
Visitor List
Maintained on FA serving an MN
Maps MN’s home address to its MAC address and Home Agent address
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Working 2 3
Home Agent 4
Foreign Agent
Mobile
Node
Internet 1 5
Correspondent Host
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JACK : IP of Correspondent Host
YOU: IP of Mobile Host (home address)
MOM: IP Address of Home Agent
HOTEL: IP Address of Foreign Agent. (CoA)
YOU
Dst
Src
Message
YOU
JACK ….
Tunnel
IP Header
Dst
Src
MOM
PACKET
HOTEL
MOM ….
HOTEL
Outer IP Header
Dst
INTERNET
Src
Message
YOU
JACK ….
IP Header
JACK
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20. Dest Address = Addr of MN
IP in IP encapsulation
Ver HL
TOS
Total Length
Outer
Header
Identification
Flags
Fragm. Offset
TTL
Protocol=4
Header Checksum
Src Address = HA Addr
Dest Address = CoA of MN
Ver HL
TOS
Total Length
Inner
Header
Identification
Flags
Fragm. Offset
TTL
Protocol
Header Checksum
Src Address = Addr of CN
Dest Address = Addr of MN
IP PAYLOAD
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21. Minimal Encapsulation
Tunneled to
care-of-address
Ver HL
TOS
Total Length
Identification
Flags
Fragm. Offset
Outer
header
TTL
Proto=55
Header Checksum
Ver HL
TOS
Total Length
Src Address = Addr of home agent
Identification
Flags
Fragm. Offset
Dest Address = Care-of-addr of mobile
TTL
Protocol
Header Checksum
Protocol S
Reserved
Header Checksum
Src Address = Addr of CN
Minimal
Inner header
Src Address = Addr of CN
Dest Address = Addr of MN
Dest Address = Addr of MN
IP PAYLOAD
IP PAYLOAD
Encapsulated using
Minimal Encapsulation
Method
Packet comes from
Correspondent host
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Internet Protocol v6
128 bit addresses as compared to 32 bits in v4.
1038 possible addresses : every electronic device can have an IP
Static header with 40 bytes,optional extension header.In v4 it goes upto 60 bytes
Routing extensions to provide for host mobility
Autoconfiguration : Newly attached host can learn its new IP
Better security (IP authentication Header)
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23. Triangular Routing Problem2 3
Home Agent
Foreign Agent 4
Mobile
Node
Internet 1 5
All traffic to MN goes through Home agent
Correspondent Host
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Solutions in MIP v6
Let the CN (JACK) know the current mobility binding (HOTEL)
They will store this binding.
They will use this binding to directly send the packets to the current location of the mobile node
They will again use encapsulation since the care-of-address may not be always collocated at the mobile node (foreign agent should decapsulate).
Correspondent nodes should support the binding protocol: Need for modification at correspondent nodes
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How to know the binding
Let the mobile node inform the correspondent host For example when it receives a packet from a correspondent host
Let the home agent inform the correspondent host. This is the method chosen, since it is easier to establish security association between a home agent and a correspondent host
Binding update should be secure so the malicious users can not send binding updates to the corresspondent hosts without authenticating themselves
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Binding Update
YOU
Dst
Src
IP Payload
YOU
JACK ….
MOM
First Packet
INTERNET
Foreign
Agent F
Other
Fields
Dst
Src
IP Payload
YOU
JACK ….
Other Packets
Dst
Src
IP Header
Dst
Src
Binding Update
(YOU,HOTEL )
IP Payload
YOU
JACK ….
HOTEL
JACK ….
Inner IP Header
Outer IP Header
JACK
YOUHOTEL
.....
Binding Cache
Packet Transport from a Correspondent Host to a Mobile
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27. Other MIPv6 optimizations
Localised mobility management:
Uses Hierarchical MIPv6 (HMIPv6) to allocate a local Home Agent (Mobility Anchor Point, MAP) in the visited network.
MNs only need to update the local MAP whenever they move within the local domain
Saves sending Binding Updates to all CNs every time the MN moves
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28. Optimizations (contd..)
The foreign Agent can be done away with if required
The protocol enables the node itself to do encapsulation-decapsulation
The node acquires its own local IP via Autoconfiguration and registers it with HA
IPv6 provides security protocols hence simplifying the authentication process
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Conclusion
With the unavoidable advent of IPv6, Mobile IPv6 will become the prevalent technology for providing seamless connectivity as we roam
With continuing research into areas like Hierarchical Mobile IP and the likes, the current protocol is only going to improve
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30. Mobile IP – Stay connected
THANK YOU
Mobile IP – Stay connected
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QUESTIONS ?
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