The Radio Access Network (RAN) architecture proposed by the Open RAN (O-RAN) Alliance separates Baseband Unit (BBU) functionalities in Central Unit (CU), Distributed Unit (DU) and Radio Unit (RU). The first two of these units are candidates of being deployed as fully virtual functions hosted on Commercial off the Shelf (CotS) hardware. In doing so, their dynamic deployment between different sites according to the different services requirements becomes an attractive solution to maximize a networks efficiency. In this paper it is proposed the dynamic allocation of transport network resources, through a drop-in Software Defined Network (SDN) controller. By duplicating and processing control plane messages at the sdn controller, it is adressed the resource allocation perData Radio Bearer (DRB) for each User Equipment (UE) in the transport network. This in turn will enable the adaptive relocation of computing resources in the network while ensuring traffic prioritization. In this work it is implemented such a SDN controller, targeting F1 interface communication between CU and DU. It is delineated which messages of the F1 Application Protocol (F1AP) control plane protocol are instrumental to realize the proposed framework. This is followed by the demonstration of the dynamic real-time flow setup per F1 User Plane (F1U) tunnel for each UE session.