Fixed-mobile Convergence in TISPAN/3GPP IMS

Great efforts for protocol and architecture standardization are being made towards converged IP based telecommunication networks merging the wireless (3GPP/2) and the fixed worlds (ETSI TISPAN) towards the so called Next Generation Network (NGN).§§NGNs are envisioned as the seamless integration of different access network technologies requiring a converged network architecture that allows true access technology independence when accessing services. The promising IP Multimedia Subsystem (IMS) is being considered the Fixed Mobile Convergence (FMC) enabler.§§Mobility management over heterogeneous networks is a major requirement for FMC systems. Users expect an always best connected solution that provides seamless services anywhere, anytime and anyhow. How IMS can provide service continuity when changing the network access point is a complex matter of study arising many questions: Traf?c anchoring architecture or a distributed one? Network- or mobile station-based? At network layer or application level? Mobile IP or SIP? These questions have not a simply yes/no answer. An adaptive and autonomous but still ef?cient mobility management solution is called for the envisioned IMS-based NGN.