Simultaneous Mobility Support with IEEE 802.21 Media Independent Handover

Abstract

The simultaneous mobility is a special case when two communication nodes start handover at about the same time. The IEEE 802.21 Media Independent Handover (MIH) and the Media-independent Pre-Authentication (MPA) techniques have been integrated to improve heterogeneous handover performance; however, they cannot resolve the simultaneous mobility problem. Hence, this article proposes an enhanced IEEE 802.21 MIH in order to resolve the simultaneous mobility problem. We first introduce new messages and service primitives for handover information exchange between the Point of Server (PoS) and the mobile node (MN) in the enhanced IEEE 802.21 MIH services. In addition, we extend the handover execution function of the mobility manager (MM) on the MN, and also enhance the intelligence of the PoS. When the MN and the corresponding node (CN) establish a connection, their MMs will advise the IP address of their corresponding PoSs to each other. If the MN starts handover, its MM will send a message with its new IP address to the PoS of the CN. After completing the handover procedure and attaching the new network, the MN performs the information query procedure to inquire its PoS about the latest IP address of the CN to check whether the CN also moves simultaneously. Furthermore, the Master-Slave Determination procedures derived from H.245 are proposed on the PoS in order to handle the racing conditions fairly when two nodes in a simultaneous mobility issue the re-establishment process at about the same time. We demonstrate the message flows of the simultaneous mobility based on the enhanced IEEE 802.21 MIH separately with two mobility protocols, SIP and MIPv6. Mathematical analysis presents that the handover latency can be shortened with our proposal.