IP Multimedia System: general aspects and migration perspectives Dr. Leo Lehmann, OFCOM Switzerland

This presentation gives an introduction to the architecture of the IP Multimedia Subsystem (IMS). It describes the standardization history of IMS and explains the major functional elements of IMS. Furthermore the relationship with UTRAN and eUTRAN based access networks is exemplified. Considering the Next Generation Network (NGN) architecture, as specified in the Y.2000 series by ITU-T, the given presentation elucidates the IMS integration into the NGN service stratum and the relationship between the related 3GPP functional entities and the NGN functional entities, as specified by the ITU-T. Finally some typical general migration scenarios with regard to the IMS realization in mobile and fix-mobile converged networks are presented.