presented by: indhra priya shanmugam submitted to: professor ivan stojmenovic

Mobile Communications-Network Protocols/Mobile IP

Presented by: Indhra Priya ShanmugamSubmitted To: Professor Ivan Stojmenovic

WHY MOBILE IP

• The node must change its IP address whenever it changes its point of attachment. (impossible for a node to maintain transport and

higher layer connections when the node changes location)

• Host-specific routes must be propagated throughout much of the Internet.

(does not scale very well)

Indhra P Shanmugam, Wireless Networks and Mobile Computing

• Mobile IP is an Internet Engineering Task Force (IETF) standard communications protocol that is designed to allow mobile device users to move from one network to another while maintaining a permanent IP address.


http://en.wikipedia.org/wiki/Internet_Engineering_Task_Force

http://en.wikipedia.org/wiki/Protocol_(computing)

• Mobile Node (MN)– system (node) that can change the point of connection

to the network without changing its IP address• Home Agent (HA)

– system in the home network of the MN, typically a router– registers the current location of the MN, tunnels IP datagram's to

the COA• Foreign Agent (FA)

– system in the current foreign network of the MN, typically a router– De-tunnels and delivers datagram's to the MN

• Care-of Address (COA)– address of the current tunnel end-point for the MN (at FA or MN)– actual location of the MN from an IP point of view– can be chosen, e.g., via DHCP

• Correspondent Node (CN)– communication partner


HOW MOBILE IP WORKS


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FUNCTIONS OF MOBILE IP

• The main functions of Mobile IP are:

1.Agent Advertisement2.Registration3.Tunneling


AGENT ADVERTISEMENT

• Agent Discovery• MN detect whether its has moved and it is

connected to Home Network (HN) or Foreign Network (FN)

• Agent Advertisement• Routers broadcast an advertisement to links to

offer services• ICMP Router Advertisement Message.• Two types of Message

» Agent Advertisement» Agent Solicitation


• Agent Solicitation

– When a MN needs information about Foreign agents, it broadcasts Solicitation messages

– Foreign Agents respond with a router advertisement message directly to the MN.


Type: 10Code: 0Reserved: 0Checksum: 0

AGENT ADVERTISEMENT• type = 16• length = 6 + 4 * #COAs• R: registration required• B: busy, no more

registrations• H: home agent• F: foreign agent• M: minimal encapsulation• G: GRE encapsulation• r: =0, ignored• T: FA supports reverse

tunneling• reserved: =0, ignored


REGISTRATION

• MN communicate their reachability to HA• MN request service when visiting FN• MN inform HA the current COA• Deregister


REGISTRATION CRTITERIA

• There are 2 types Registration Procedures:– Through Foreign Agent– Directly with Home Agent

1. If MN registering a Foreign Agent COA , then register via FA

2. If MN got an advertisement from FA, then register via Foreign Agent

3. If MN has returned to HA, it registers directly with its Home Agent

4. If MN is using Co-located COA, it registers naturally with its HA


REGISTRATION MESSAGE

– Registration messages in Mobile IP use the User Datagram Protocol (UDP).

– There are two registration Message:» Registration Request» Registration Response


AUTHENTICATION

• To allow additional security for registration process, Mobile IP defines registration extensions:

» Mobile-Home Authentication extension» Mobile-Foreign Authentication extension» Foreign-Home Authentication extension

• Each extension includes SPI and IP address that contains secret information needed to compute others

• The default algorithm uses MD5(Message Digest) to authenticate the request and response messages


AUTHENTICATION FORMAT

• Secret key is used both – Prefix and Suffix to data• SPI selects authentication algorithm, mode and secret

key used in authenticator• SENDER = Message + algorithm +secret key• RECEIVER = Message Received + algorithm to be

used + Secret Key• IF Sender = Receiver ( Authenticated)


TUNNELING

• After successful Registration, Mobile IP requires encapsulation to deliver datagram

• The encapsulation and decapsulation methods are called tunneling

• When data transfer, Home agent intercepts the data sent to MN and tunnels them to the COA of MN

• There are 3 main Tunneling algorithm:» IP-in-IP Encapsulation (Default)» Minimal Encapsulation» Generic Record Encapsulation (GRE)


IP-IN-IP ENCAPSULATION

• IP datagram is encapsulated within another IP datagram. Data is carried as payload

• Outer header is added before existing IP header• Additional headers can be added for security reasons


MINIMAL ENCAPSULATION

• Devised to avoid redundancy from IP-in-IP• Datagram should be not fragmented before

encapsulation• Minimal Forwarding Header is used• No additional IP header is added


GRE ENCAPSULATION

• It is more general method. Also used for many other Protocols


REVERSE TUNNELING

• Tunneling starts at the HA and is decapsulated by either FA or MN (end)

• Decapsulation depends on type of COA» Foreign Agent COA – FA» Co-located COA – MN

• When MN sends message to CN, the process is called Reverse Tunneling


ROUTE OPTIMIZATION

• One of the problem with Mobile IP – Triangle Routing• To overcome this, Route Optimization is implemented


ROUTE OPTIMIZATION OVERVIEW

• There are 4 operations in Route Optimization:– Binding Caches:

• It maintains COA of mobile nodes and directly tunnels data to MN

– Manage Smooth Handoff:• When MN moves from one FA to another

– Registration Keys:• Securely perform operations for handoff and

authentication– Using Special Tunnels:

• To perform tunneling in special cases


ROUTE OPTIMIZATION MESSAGE FORMATS

• There are 4 Message Formats:– Binding Warning Message:

• To warn MN that it has no cache entry• When MN detunnels and is not in current FA

– Binding Request Message:• Request for MN’s current mobility binding

– Binding Update Message:• Update or notify MN’s current mobility binding

– Binding Acknowledge Message:• Acknowledge the receipt of update message


MOBILE IP - ROUTE OPTIMIZATION


SECURITY IN MOBILE IP

• Network Security in Mobile IP is important.• Compromise in Security may lead too:

» Unauthorized access» Disclosure of information» Unreliability» Denial of Service» Corruption of Data


SECURITY ENHANCEMENTS

• Security can be maintained in Mobile IP using:» Confidentiality» Authentication» Non-Repudiation» Integrity» Authorization» Security in IP» Firewall


FUTURE OF MOBILE IP

• Mobile IP is the Voice and Data of Future• It is currently used in:

» 3G Wireless, CDMA, GSM» VOIP Services» VPN» CISCO» WLAN» IOS» Campus Mobility» Metro Mobility


Question – 1: In Mobile IP Protocol, Explain with Diagram how the Registration Process takes place:a) When Mobile Node (MN) is in Home Network (HN)b) When Mobile Node (MN) is in Foreign Network (FN)


Question – 2: In Mobile IP Protocol, a) What are the three main Tunneling algorithm?b) Which approach is used to solve the Triangle Routing Problem and explain its message Format ?


Answer : a) The three main Tunneling algorithm are :

IP-In-IP EncapsulationMinimal EncapsulationGRE Encapsulation

b) Route Optimization. Its message format are : Binding Warning Message

Binding Request Message

Binding Update Message

Binding Acknowledgement Message

Question – 3: The given diagram explains how datagrams are transferred from Correspondent Node (CN) to Mobile Node (MN) in the current Foreign Agent (FA) using Mobile IP Protocol. Consider that the Mobile Node moved from Foreign Agent Old to Foreign Agent New. Using Route Optimization, Complete the following diagram, explaining how a Mobile Node can move from FA old to FA new.


Answer:


REFERENCES

1. C. Perkins, Mobile IP: Design Principles and Practice, Addison-Wesley Longman

2. Handbook of Wireless Networks and Mobile Computing, Edited by Ivan Stojmenovic

3. Stefan Raab and Madhavi W. Chandra, Mobile IP Technology and Applications

4. Abdul Sakib Mondal, Mobile IP – Present State and Future

5. Dr.-Ing. Jochen Schiller, http://www.jochenschiller.de/6. http://ubiquity.acm.org/article.cfm?id=12178247. http://en.wikipedia.org/wiki/Mobile_IP#Applications


presented by: indhra priya shanmugam submitted to: professor ivan stojmenovic

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