I. Introduction
The anticipated complexity of 5th Generation (5G) mobile networks pushes towards minimizing human engagement and relying on vast amounts of (quasi-) real-time monitoring data in a new era of Data-Driven Control & Management (DDCM). A crucial aspect of DDCM regards delivering network monitoring as a service on a per-use-case basis. Currently, there are different monitoring tools targeting specific use cases and network domains, namely, the 5G Core Network (CN), the transport network, and the Radio Access Network (RAN), hence a requirement for a multiservice execution environment to unify all of the earlier into customized virtual views tailored to use case requirements. Dynamic bit rate video optimization poses such a representative example, requiring to utilize both User Equipments (UEs) and RAN information, each monitored by different tools. Last, complexity gets further amplified by the concept of network "slicing" into multiple (possibly recursive) logical networks (a.k.a. "slices") composed of virtual and/or physical resources over a common infrastructure, with implications on monitoring spanning from practical up to policy contradictions between the various stakeholders.