NEC NTT Docomo Juniper Networks China Mobile The evolution of cellular mobile communication systems is aligned with an increasing demand for customized deployments, energy efficiency, dynamic re-configurability and the integration and use of other network technologies, such as non-cellular radio access technologies and non-terrestrial networks. In order to achieve and maintain the expected service quality and continuity, such systems should be designed and controllable end-to-end, taking all involved network domains and segments into account. This document discusses an end-to-end system from an advanced use cases perspective and substantiates the demand for solutions to share information and enable control interfaces between all connected network domains, including the mobile communication system and the transport network that stretches up to the data networks that host service instances. Two architectural principles are described and discussed in the view of existing or new IETF technology that enables end-to-end mobile traffic treatment and steering in such complex and dynamically changing networks.