21-12-2012, 12:21 PM
MOBILE IP
MOBILE IP.pptx (Size: 668.87 KB / Downloads: 29)
Mobile IP solves the following problems:
If node moves from one link to another without changing its IP address, it will be unable to receive packets at the new link
If a node changes its IP address when it moves, it will have to terminate and restart any ongoing communications each time it moves
Mobil IP solves these problems in secure, robust, and medium-independent manner whose scaling properties make it applicable throughout the entire Internet
Mobile IP
Mobile IP (or IP mobility) 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.
What Are the Requirements for Mobile IP?
A mobile node must be able to communicate with other nodes after changing its link-layer point-of-attachment to the Internet
Must be able to communicate using its home (permanent) IP address, regardless of its current link-layer point-of-attachment to the Internet
Must be able to communicate with other computers that do not implement the Mobile IP mobility functions
The Mobile IP implementation should be limited only to the mobile nodes themselves and the few nodes which provide special routing functions on their behalf
Must not be exposed to any new security threats over and above those to which any fixed node on the Internet is exposed
Terminology
Home network
The home network of a mobile device is the network within which the device receives its identifying IP address (home address).
Home address
The home address of a mobile device is the IP address assigned to the device within its home network.
Foreign network
A foreign network is the network in which a mobile node is operating when away from its home network.
Care-of address
The care-of address of a mobile device is the network-native IP address of the device when operating in a foreign network.
Mobile IP mechanismsAgent Discovery
MN discovers its location (home network, foreign network)
MN learns a COA
Registration
MN securely signals the COA to the HA (via the FA)
Tunneling
MN encapsulates IP packets from CN and sends them to the COA
FA (or MN) decapsulates these packets and sends them to the MN
Route Optimization in Mobile IP
Route optimization
HA provides the CN with the current location of MN (FA)
CN sends tunneled traffic directly to FA
Optimization of FA handover
Packets on-the-fly during FA 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
Extension: not part of the core Mobile IP (RFC 3344)
Violates compatibility (CN needs to be Mobile-IP-aware)
Security problems
Mobile IP Summary
Allows node mobility across media of similar or dissimilar types
Uses the Mobile Node’s permanent home address when it changes its point of attachment to the Internet
Not requires any hardware and software upgrades to the existing, installed base of IPv4 hosts and routers – other than those nodes specifically involved in the provision of mobility services
Mobile Node must provide strong authentication when it informs its Home Agent of its current location
Uses tunneling to deliver packets that are destined to the Mobile Node’s home address
3 main entities: Mobile Nodes, Foreign Agents and Home Agents
3 basic functions: Agent Discovery, Registration, Packet Routing