Disclosed is a technique for guaranteeing high-level QoS for emergent traffic to enable the transmission of the traffic. According to the technique, when a transmission unit 110 sends a content to a reception unit through a network 130, identification information is added to a data packet including the content to indicate that the data packet is a packet to be transmitted to a permitted content using node 150. This packet is duplicated by a network node (e.g., an intermediate node (management node) 140) and forwarded to both the reception unit and the permitted content using node. The content stored on the permitted content using node can be referred to check whether this content is to be transmitted in high priority. A content owner can get compensation (e.g., the cost required for high-priority network transmission) by providing the right of use of the content to the permitted content using node.