Recent progress in sensor and communications have opened the road for the ever-growing development of Internet of Things (IoT) services, where a massive number of devices require access to the transport network, using widely deployed fixed or wireless access technologies and/or mobile Radio Access Network (RAN). Supporting IoT in the RAN is challenging, as IoT services may generate a multitude of short and bursty sessions, thus impacting the performances of mobile users sharing the same RAN. To this end, network slicing is envisioned as a promising design approach to enable optimal support for heterogeneous service segments sharing the same RAN, i.e., the key requirement of the upcoming fifth generation (5G) mobile network. In this paper, we propose a network slicing solution for enabling efficient coexistence of enhanced mobile broadband (eMBB) and IoT services, sharing the same RAN. Our solution aims at efficiently sharing the bandwidth resources among different slice segments, while considering their requirements. We validate the proposed solution in a 5G prototype based on the Cloud Radio Access Network (C-RAN) architecture, which makes use of the Open Air Interface (OAI) platform and the FlexRAN SDN controller. The main goal of our work is to validate the feasibility of the prototype of supporting the creation and configuration of network slices on-demand, taking into account diverse requirements that are elaborated by a northbound SDN-based slicing application. By means of emulations, we show that the prototype is capable to dynamically manage the slicing process in real-time, providing isolation among eMBB and IoT services.