The use of centralized signal processing for dense urban mobile networks is gaining interest both in research and in industry. Gathering most of the base station functionalities in a processing pool would enable capacity sharing and the implementation of advanced techniques such as coordinated multi-point. Nevertheless, this puts stringent requirements on the network interconnecting the processing pool and the sites, especially in terms of maximum latency. In this paper, we provide results for dimensioning the fronthaul network that are obtained through modelling and discrete-event simulation. We model the full protocol stack for the network end-to-end in order to use realistic application-layer traffic and user behavior models. Our results show that the fronthaul latency should be kept below 0.6 ms in order to ensure optimal performances for the application.