In this paper, we study the scalability issues of SDNized wireless networks, specifically those relevant to mobility management. We study the improvements in handover delays: i) when a proposed proactive mobility management algorithm is implemented, ii) when the controller delegates partial control of mobility management to the forwarding entities. For the implementation of the proposed approaches on the OpenFlow network, the paper also suggests potential extensions to OpenFlow protocol. The contributed approaches are validated on a full scale demonstrator and results show that proactive outperforms reactive and the delegated control approach performs better than proactive for smaller topology sizes. Furthermore a proposal for LTE-X2 specific control delegation is discussed as use-case.