IP MultiMedia Subsystem (IMS) : un outil de convergence fixe-mobile

This paper gives an overview of business stakes and technical progress about IMS (IP Multimedia Subsystem). With the generation of IP as universal protocol for transport, vocal services have to migrate from dedicated PSTN toward VoIP solutions. This is a technical challenge, especially for quality of service and security (as IP having not been conceived for real time). This radical change, which coincides with the emergence of fixed mobile convergence, destabilizes the economic conditions for the operators and services providers. IMS specifications are an answer to this challenge. Coming from the mobiles to facilitate multi-media services in UMTS area, IMS was adopted and extended for the fixed Next Generation network. This architecture, natively IP, multi-media oriented, completely, fixed and mobile, will support various applications liberated from strong network constraints. This tool would unite IP dynamics and creativity with high quality of service (one of the main winning cards of operators).