Patent ID: 8379655

Claim:
A data network comprising: at least one policy manager arranged to reserve communication resource for call sessions, a plurality of proxy-call session control functions serving user equipments, each proxy-call session control function of the plurality of proxy-call session control functions being arranged to request resource reservation from an associated policy manager when initializing a call session for a user equipment served by the proxy-call session control function; a serving-call session control function arranged to: receive a first call session setup message for initializing a first call session between an originating user equipment and a terminating user identity; determine a set of terminating user equipments associated with the terminating user identity, the set of terminating user equipments having an associated set of proxy-call session control functions of the plurality of proxy-call session control functions that serve the user equipments of the set of terminating user equipments; and transmit a call session initialization message for each user equipment of the set of terminating user equipments to an associated proxy-call session control function of the set of proxy-call session control functions associated with the user equipment, the call session initialization message comprising a session identity indication for the first call session and a forking indication arranged to indicate if the first call session is a forked call session; and wherein at least one of a first proxy-call session control function of the set of proxy-call session control functions and a first policy manager supporting at least a proxy-call session control function of the set of proxy-call session control functions is arranged to restrict a combined resource reservation for a first and second user equipment of the set of terminating user equipments to a resource requirement of only one of the first and second user equipment in response to a detection that call session initialization messages for the first and second user equipment have matching session identity indications and forking indications indicative of a forked call session setup, and wherein the serving-call session control function is arranged to determine a serving policy manager for each proxy-call session control functions of the set of proxy-call session control functions, and to include the forking indication only for proxy-call session control functions of the set of proxy-call session control functions that have a common serving policy manager.