Method for establishing a communication link between a communication end device terminal via a communication network, wherein the communication network has a plurality of subnetworks (307, 311, 315), with a first subnetwork and a second subnetwork, wherein a first identification entity is arranged in the first subnetwork and a second identification entity is arranged in the second subnetwork in order to identify the communication device, wherein a subnetwork identifier is assigned to each subnetwork (307, 311) of the communication network, wherein a management entity is arranged in the communication network and manages an assignment of the communication end device to one of the two subnetworks (307, 311), and wherein the method comprises the following steps: Receiving an identification of the communication end device by the first identification entity of the first subnetwork, wherein the identification identifies the communication end device; Identifying the communication end device by the first identification entity on the basis of the identification of the communication end device; Assigning a subnetwork to the communication end device by the management entity on the basis of an assignment of a subnetwork identifier to the communication end device, and; Establishing a communication link with the communication end device via the first subnetwork if the subnetwork identifier assigned to the identification of the communication end device corresponds to the subnetwork identifier of the first subnetwork; or establishing a communication link with the communication end device via the second subnetwork if the subnetwork identifier assigned to the transmitted identification and the subnetwork identifier of the first subnetwork are different, characterized in that in the assignment step, the management entity transmits the subnetwork identifier assigned for identification of the communication end device to the first identification entity, and wherein if the subnetwork identifier assigned for the identification of the communication end device and the subnetwork identifier of the first subnetwork are different the first identification entity transmits the transmitted subnetwork identifier to the communication end device, or if subnetwork identifier assigned for the identification of the communication end device and the subnetwork identifier of the first subnetwork are different, the first identification entity transmits the transmitted subnetwork identifier to the second identification entity, wherein the communication link is established via the second subnetwork if the subnetwork identifier assigned to the transmitted identification is the subnetwork identifier of the second subnetwork. Receiving an identification of the communication end device by the first identification entity of the first subnetwork, wherein the identification identifies the communication end device; Identifying the communication end device by the first identification entity on the basis of the identification of the communication end device; Assigning a subnetwork to the communication end device by the management entity on the basis of an assignment of a subnetwork identifier to the communication end device, and; Establishing a communication link with the communication end device via the first subnetwork if the subnetwork identifier assigned to the identification of the communication end device corresponds to the subnetwork identifier of the first subnetwork; or establishing a communication link with the communication end device via the second subnetwork if the subnetwork identifier assigned to the transmitted identification and the subnetwork identifier of the first subnetwork are different, characterized in that in the assignment step, the management entity transmits the subnetwork identifier assigned for identification of the communication end device to the first identification entity, and wherein if the subnetwork identifier assigned for the identification of the communication end device and the subnetwork identifier of the first subnetwork are different the first identification entity transmits the transmitted subnetwork identifier to the communication end device, or if subnetwork identifier assigned for the identification of the communication end device and the subnetwork identifier of the first subnetwork are different, the first identification entity transmits the transmitted subnetwork identifier to the second identification entity, wherein the communication link is established via the second subnetwork if the subnetwork identifier assigned to the transmitted identification is the subnetwork identifier of the second subnetwork.