Mobile ip

Nitheesh K

VIAHECS030Department of computer science

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Mobile IP

Mobile IP was designed to allow mobile device users to move from one network to another .Enables hosts to stay connected to the Internet

regardless of their location.Enables hosts to be tracked without needing to

change their IP address.Requires no changes to software of non-mobile

hosts/routers.Has no geographical limitations.Supports security.

Standardized by IETF .

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Mobile IP EntitiesMobile Node (MN)

The entity that may change its point of attachment from network to network in the Internet.

Two addresses:- 1. Home address – IP address assigned to the device

within its home network . 2. Care-of address (COA)– IP address of the device when it

is operating in a foreign network. Identifies Mobile Node’s current location. Sent by Foreign Agent to Home Agent when MN

attaches. Usually the IP address of the Foreign Agent.

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Mobile IP EntitiesHome Network – The network within which the

device receives its Home address Home Agent (HA)

Stores information about Mobile nodes whose permanent Home address is in Home Agent’s Network.

Located on home network of Mobile Node.Does mobility binding of MN’s IP with its COAForwards packets to network when MN is away

Does this through encapsulation

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Mobile IP Entities contd.Foreign network – Network in which the Mobile Node is

away from its Home network.Foreign Agent (FA)

Stores information about mobile nodes visiting its network.

If MN is away from HA then it uses a FA to send/receive data to/from HA

Advertises Care-of addresses which are used by Mobile IP.

Decapsulates messages for delivery to MNBinding – Association of Home address with Care-of

address.Correspondent Node(CN) – End host of MN.CS 640 5

Mobile IP OperationAgent Discovery

HA’s and FA’s broadcast their presence on each network to which they are attached

MN’s listen for advertisement and then initiate registration

Encapsulation – Attaching COA to the packet with HADecapsulation –Detaching COA to the packet with HARegistration

When MN is away, it registers its COA with its HA Registration happens as often as MN changes networks There is a specific lifetime for service for registration There is also a de-registration process if an MN returns

home

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Mobile IP OperationA MN listens for agent advertisement and then

initiates registrationAfter receiving the registration request from a MN,

FA request to HAThe HA acknowledges and registration is completeHA intercepts all packets destined for MNHA then encapsulates all packets addressed to MN

and forwards them to FAFA decapsulates all packets addressed to MN and

forwards them via hardware address

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Registration Process

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Tables maintained on routersMobility Binding Table

Maintained on HA of MN Maps MN’s home address

with its current COA

Visitor List Maintained on FA Maps MN’s home address

HA address

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Mobile IP Tunneling

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Across Internet

Mobile IP ProblemsSingle HA model may be damaged

Possible solution – have multiple HAFrequent reports to HA if MN is moving

ApplicationsFound in Wired and Wireless environments.Able to carry mobile devices across Multiple

LANS.

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