Transcript Indhra Priya Shanmugam. Mobile Communications

Mobile Communications-Network
Protocols/Mobile IP
Presented by: Indhra Priya Shanmugam
Submitted 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)
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• 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.
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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
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HOW MOBILE IP WORKS
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FUNCTIONS OF MOBILE IP
• The main functions of Mobile IP are:
1.Agent Advertisement
2.Registration
3.Tunneling
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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
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• 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: 10
Code: 0
Reserved: 0
Checksum: 0
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AGENT ADVERTISEMENT
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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
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Computing
REGISTRATION
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MN communicate their reachability to HA
MN request service when visiting FN
MN inform HA the current COA
Deregister
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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
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REGISTRATION MESSAGE
– Registration messages in Mobile IP use the User
Datagram Protocol (UDP).
– There are two registration Message:
» Registration Request
» Registration Response
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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
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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)
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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)
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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
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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
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GRE ENCAPSULATION
• It is more general method. Also used for many other
Protocols
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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
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ROUTE OPTIMIZATION
• One of the problem with Mobile IP – Triangle Routing
• To overcome this, Route Optimization is implemented
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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
Indhra P Shanmugam, Wireless Networks and Mobile
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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
Indhra P Shanmugam, Wireless Networks and Mobile
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MOBILE IP - ROUTE
OPTIMIZATION
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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
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SECURITY ENHANCEMENTS
• Security can be maintained in Mobile IP using:
» Confidentiality
» Authentication
» Non-Repudiation
» Integrity
» Authorization
» Security in IP
» Firewall
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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
Indhra P Shanmugam, Wireless Networks and Mobile
Computing
Indhra P Shanmugam, Wireless Networks and Mobile
Computing
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)
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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 Encapsulation
Minimal Encapsulation
GRE Encapsulation
b) Route Optimization. Its message format are :
Binding Warning Message
Binding Request Message
Binding Update Message
Binding Acknowledgement Message
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Computing
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.
Indhra P Shanmugam, Wireless Networks and Mobile
Computing
Answer:
Indhra P Shanmugam, Wireless Networks and Mobile
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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=1217824
7. http://en.wikipedia.org/wiki/Mobile_IP#Applications
Indhra P Shanmugam, Wireless Networks and Mobile
Computing
Indhra P Shanmugam, Wireless Networks and Mobile
Computing