A technique for flexibly performing processes depending on the type of a path for providing an additional service when there are a plurality of paths for providing additional services for the same session between terminals communicating with each other over a network is disclosed. According to the technique, when a mobile terminal (MN 100) establishes a QoS path using NSIS to a corresponding node (CN 124) on different types of data communication paths, a signaling message including information (MIE) representing the path type is created and transmitted. Each node (QNE) with an NSIS QoS function, which has received the message, identifies a plurality of QoS paths by comparing the MIE, a session identifier and a flow identifier, and performs processing of the QoS paths according to control information (CI) from MNs or/and the policy which the QNE has.