Seamless handoff in mobile IP

An Internet Protocol based wireless access network, comprising:

• a lower layer complying with Open Systems Interconnections (OSI) model wherein a handoff starting time is obtained;
• a mobile node adapted to obtain a new care-of address from a new sub-network router, and to issue a request message via the new sub-network router requesting a new binding, upon being notified from the lower layer of the OSI model that a connection with an old sub-network router will be discarded within a predetermined amount of time;
• and
• a base node adapted to create the new care-of address binding upon receiving the request message from the mobile node and to issue, at the same time, two registration reply messages being sent to both the old sub-network router and the new sub-network router, including:
• a registration reply message to the mobile node via the new sub-network router indicating that the new care-of address binding has been created, wherein the base node is adapted to delete an old care-of address binding therefrom upon receiving a deregistration request message and
• a deregistration binding acknowledgment message to the mobile node via the old sub-network router indicating that the old care-of address binding has been deleted;
• wherein the mobile node and the base node are further adapted to utilize the deregistration binding acknowledgment message to synchronize the transfer of old care-of address data packets stored on the old sub-network router from the base node to the mobile node in a synchronized manner, the base node sending the two registration reply messages including the deregistration binding acknowledgment message after receiving the registration request message and using the deregistration binding acknowledgment message as a synchronization point.

A method of handing off a mobile node from an old sub-network router to a new sub-network router in an Internet Protocol based wireless access network, comprising:

• obtaining a handoff starting time from a lower layer complying with Open Systems Interconnection (OSI) model;
• using information from the lower layer of the OSI model to notify the mobile node that a connection with the old sub-network router will be discarded within a predetermined amount of time;
• obtaining a new care-of address for the mobile node from the new sub-network router;
• sending a request message from the mobile node to a base node via the new sub-network router requesting a new binding, the base node being predetermined one of a home agent, a gateway foreign agent, and a mobility anchor point;
• creating a new care-of address binding in the base node;
• issuing two registration reply messages from the base node to the mobile node to both the old sub-network router and the new sub-network router;
• a registration reply message via the new sub-network router indicating that the new care-of address binding has been created and
• a deregistration reply message (DRR) via the old sub-network router indicating that the old care-of address binding has been deleted;
• and
• utilizing the deregistration reply message (DRR) to synchronize a transfer of old care-of address data packets stored on the old sub-network router from the base node to the mobile node, the home agent sending the two registration reply messages including the DRR after receiving the registration request message and using the DRR as a synchronization point.