The advent of SDN in mobile networks enables mobility management solutions with a flow-centric perspective. Based on SDN/NFV paradigms the softwarized data plane encourages new architectures for flexible mobile networks with autonomous adaptation and self-optimization capabilities. However, the inherent challenges of the SDN control plane such as scalability or protocol versioning issues are often neglected in those designs. In this work we demonstrate a possible transformation from the rather monolithic 3GPP architecture to a more flexible SDNized network by means of a vertical mobility management solution. We analyze restrictions of the current OpenFlow protocol and propose various extensions as enablers for an SDNized 3GPP architecture that addresses said control plane issues. Using the kernel Berkeley Packet Filter, we show a feasible realization of the extensions, which supports faster integration of novel flexible mobility management approaches.