  Mobility support for the next generation IPv6 networks has been one of the
recent research issues due to the growing demand for wireless services over
internet. In the other hand, 3GPP has introduced IP Multimedia Subsystem as the
next generation IP based infrastructure for wireless and wired multimedia
services. In this paper we present two context transfer mechanisms based on
predictive and reactive schemes, to support seamless handover in IMS over
Mobile IPv6. Those schemes reduce handover latency by transferring appropriate
session information between the old and the new access networks. Moreover, we
present two methods for QoS parameters negotiations to preserve service quality
along the mobile user movement path. The performances of the proposed
mechanisms are evaluated by simulations.
