Copyright © 2004 John Wiley & Sons, Ltd. Pre-handover signalling for QoS aware mobility management By Hakima Chaouchi* ,† and Pedro Marques Antunes In this paper we present a new approach to provide fast handover in Mobile IP. A new Pre-Handover Signalling (PHS) protocol is proposed to allow the network to achieve accurate handover decisions considering different constraints such as QoS, load balancing in the base stations, the user profile, the mobile node service requirements, etc. In addition we propose to minimize the time discovery of the new base station in order to minimize the handover latency. We propose to start the PHS as soon as the mobile node crosses a predefined critical zone area in its current location, this signalling will provide a list of candidate cells to the mobile node with corresponding priorities; the mobile node will select the highest priority base station as soon as the layer two handover occurs. We propose in the current work to use an extension of COPS (Common Open Policy Service) to support the proposed PHS mechanism and overcome the blind handover decisions of Mobile IP and improve the handover performance. Copyright © 2004 John Wiley & Sons, Ltd. Hakima Chaouchi is with LIP6, Paris VI University, Paris, France, and CTR, King’s College, University of London, London, UK. Pedro Marques Antunes is with LIP6, Paris VI University, Paris, France. *Correspondence to: Hakima Chaouchi, LIP6, Paris VI University, Paris, France. † E-mail: hakima.chaouchi@kcl.ac.uk Introduction I n order to avoid service disruption, the handover management framework must perform a smooth and/or fast handover. A smooth handover requires minimum packet loss and a fast handover requires minimum delay. The handover is composed of an initiation phase, a decision phase and an execution phase. During the initiation phase, the mobile node detects the neighbouring cells. During the decision phase, the mobile node decides to switch to the next cell. Finally, during the execution phase, the mobile node configures its wireless interface to move to the next cell. Several mobility schemes, and particularly the Mobile IP scheme, have an important drawback which is to perform all the actions related to the mobility of the node after the handover execution phase. That means the physical layer is connected to the physical layer of the new cell, but the network layer is not already configured to use the resources of the new cell. In Mobile IP, the mobil- ity actions needed to be performed after the han- dover execution are mainly the authentication, getting the new IP address and the new location registration of the mobile node. Why not perform certain mobility functions during the handover initia- tion in order to minimize the delay due to all these mobility actions? In this paper we introduce a Pre- Handover Signalling (PHS) framework to support the triggering of a predictive handover that will obviously achieve a fast handover, and provide handover decisions based on constraints other than the fading of signal strength such as the cost or the resource availability in the neighbouring cells. The rest of this paper is structured as follows. First, we present the background to this work, then we propose our PHS framework, fol- INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT Int. J. Network Mgmt 2004; 14: 367–374 Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/nem.533