1. A control device for controlling an IP core network, said IP core network comprising at least one router to an external data packet network and at least one switch connected to said at least one router, said at least one switch being connected to at least one base station of an access network, said control device comprising: a communication module configured to communicate with a mobility management entity of the IP core network and to receive state information from said entity that is representative of a mobility state and/or an IP connectivity state of a terminal; an updating module configured to update topology information representing connections existing between said at least one router, said at least one switch, said at least one base station, and terminals registered with the core network, said updating module being configured to update at least some of said topology information as a function of said state information; and a control module configured to control said at least one router and/or said at least one switch via processing rules to be applied to data streams for said terminals registered with the core network, said processing rules being defined on the basis of said updated topology information.