Post on 31-Mar-2015
Mobile Networking through Mobile IP
Presenter: Guimin Zhang
Truly Mobile Networking
Provide confident access to the Internet anytime, anywhere
Reconnection occurs automatically and noninteractively
Mobility transparent to applications and higher level protocols such as TCP
Today’s Internet Protocol
Packets are routed to destinations based on IP address
128.143.71.50 128.143.77.83
router 71 gilmer
garrett
IP Network
Apply to Mobile Networking
128.143.71.50 128.143.77.84
IP Network
Apply to Mobile Networking
128.143.71.50
IP Network
128.143.77.84
X
Mobile IP Approach
Mobile IP uses two IP addresses:
Home address: The IP address assigned to the
mobile node, making it logically appear attached to its home network.
Care-of address: An IP address at the mobile node's
current point of attachment to the Internet, when the mobile node is not attached to the home network.
Mobile Network Terminology (1)
Home network: The network at which the mobile node
seems reachable, to the rest of the Internet, by virtue of its assigned IP address.
Foreign network: The network to which the mobile
node is attached when it is not attached to its home network, and on which the care-of address is reachable from the rest of the Internet.
Mobile Network Terminology (2)
Home agent: A router on the home network that
effectively causes the mobile node to be reachable at its
home address even when the mobile node is not attached
to its home network.
Foreign agent: A router on the foreign network that
can assist the mobile node in receiving datagrams
delivered to the care-of address.
How Mobile IP Works
128.143.71.50
router 71router 77
virginia.net
IP Network
128.143.77.84
HA
128.143.71.50
router 71router 77
virginia.net
IP Network
How Mobile IP Works
128.143.77.84
HA
FA
Register
Discovery
Discovering the care-of address Registering the care-of address Tunneling to the care-of address
Agent Discovery Protocol
Extends ICMP Router Discovery protocol
ICMP Router Discovery Protocol enables hosts attached to multicast or broadcast networks to discover the IP
addresses of their neighboring routers. Agent advertisements: The mobile agent
broadcast agent advertisements at regular intervals. Agent solicitation: The mobile node broadcast or
multicast a solicitation that will be answered by any foreign agent or home agent that receives it.
Advertisement Message Formats ICMP Router Advertisement Agent Advertisement extension
Type: 16 R: register required B: busy H: home agent F: foreign agent M: minimum encapsulation G: GRE encapsulation V: Van Jacobson header compression
Advertisement Message Formats ICMP Router Advertisement Prefix Length extension
Type: 19 Prefix Length:network number of
the corresponding Router Address listed in the ICMP Router Advertisement portion of the message.
Mobile Node Move Detection
Lifetime basedThe mobile node record the Lifetime of advertisement message. If it fails to receive another advertisement from the same agent until the the Lifetime expires, it considers to find a new agent.
Network prefixes basedThe Prefix-length extension is used to determine if the newly received advertisement is in the same subnet as the mobile node’s current care-of-address.
Registration
MH: mobile host; FA: Foreign Agent; HA: Home Address
Exchange of Registration Request and Registration Reply messages: UDP using well-known port 434
Foreign Agent Consideration
Each foreign agent must be configured with a care of address
For each pending or current registration, the foreign agent maintains a visitor list entry containing: Link-layer source address of the mobile node The mobile node’s Home Address The Home Agent address The identification field The requested registration Lifetime The remaining Lifetime of the pending or current registration
Security Considerations in Registration
Danger: Registration Request works remotely to the
home agent to affect the home agent's routing table Security:
Authentication: Home agents and mobile nodes perform authentication using MD5 algorithm and key size of 128 bits.
Replay Protection: The Identification field is used to verify that a registration message has been freshly generated.
timestamp , random number
Tunneling to the Care of Address
Changes with IP Version 6
Route Optimization When it knows the mobile node's current care-of
address, a correspondent node can deliver packets directly to the mobile node's home address without any assistance from the home agent
Security Strong authentication and encryption features are
included in IP V6
Problems Facing Mobile IP
Security issues Routing inefficiency
Triangle routing Ingress filtering User perceptions of reliability Competition from other protocols
Mobile IP Related Projects
The CMU Monarch Project: Protocols for Adaptive Mobile and Wireless Networking
Portland State Secure Mobile Networking Project
State University of New York, Binghamton's Linux-Mobile IP
Stanford's Operating Systems and Networking Group's MosquitoNet
BBN Technologies' Mobile IP Security page
Reference
"Mobile Networking through Mobile IP," C. Perkins, IEEE Internet Computing, Vol. 2, No. 1, 1998.
"Mobile IP ," C. Perkins, IEEE Communications Magazine, Vol. 35, No. 5, 1997.