Cross-layer handover for SIP applications based on media-independent pre-authentication with redirect tunneling

With the media-independent pre-authentication (MPA), a mobile node (MN) performs the pre-authentication and pre-configuration to get the new care-of-address (nCoA) as the layer 3 handover before the layer 2 handover, in order to lessen handover delay. However, in reality, the MN may perform the layer 2 handover due to the link going down before completing the layer 3 handover. It will cause the packet loss if there are packets destined to the MN with the old care-of-address (oCoA). To avoid packet loss, the MPA can be enhanced with redirect tunneling (RT), denoted by MPA-RT. Before performing the link layer handover, the MN would request the old access router (oAR) to create a redirect tunnel with the new access router (nAR) after deleting the proactive handover tunnel (PHT) that was built between the MN and the nAR. Then the oAR will forward data packets to the nAR via the redirect tunnel. The nAR also starts to buffer those packets until the MN completes the link layer handover, and flushes the packets to the MN. In addition, we integrate the MPA-RT with media independent handover (MIH) and session initiation protocol (SIP) to provide a seamless handover for SIP applications. Simulation results shows that the cross-layer handover can significantly reduce the packet transmission delay and the temporary packet buffer size, as compared with current alternatives.