Mobile IP

Mobile IP

Abstract:

A few years ago we experienced a mobile phone revolution. This enabled us to maintain a telephone connection while we were on the move. Waiting around the corner, is yet another revolution all set to bend the rules of conventional computing. It is formally known as ‘Mobile Computing’. Mobile IP is the heart of mobile computing. Mobile IP is a protocol put forth by the IETF (Internet Engineering Task Force). It is designed to augment the existing Internet Protocol (IP) and provide support for maintaining Internet connection while the computer is moving. The protocol is not allowed to assume any changes in the existing IP infrastructure as large amount of investment has been already done by the companies.
Thus to ensure that the connection between the mobile node and the Internet is maintained we must device some method to deliver the packets destined to the node when it is away from its original network.

To understand Mobile IP lets consider the example of the snail mail forwarding facility of our Post Office. When a person is going away from his usual residence for some days, he can request the post office in his city to forward all his mail to his new address where he intends to go. Now the home post office takes the new address from the person and records it. Whenever mail is received, the home post office puts the mail into another envelope, puts the address of the foreign post office and sends it to the new city (foreign) post office. The foreign post office then removes the mail from the outer envelope and gives it to the original person who is temporarily in this city.

This is precisely how Mobile IP works. Mobile node intimates the home agent of its current point of attachment to the Internet. The home agent records this information and forwards any further packets destined to the mobile node to this point. At this point the foreign agent simply gives these packets to the mobile node.

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