A professional radiocommunication network infrastructure operating in packet mode includes a site controller with a specified geographic area including a base station capable of ensuring radio transmission and reception with a user terminal found in a cell attached to the base station; a centralized supervision device configured to detect if the infrastructure is in a nominal or isolated operating state; and a centralized device for associating with a centralized packet network to establish access between at least one centralized application and a first application during operation of the infrastructure detected according to a nominal state.