Abstract: A method for identifying real-time traffic hop by hop in an Internet network including a sender, a receiver, and routers in the network is provided. The method comprises steps of registering source port number and/or destination port number of the UDP respectively for RTP, RTCP and RTSP with the Internet Assigned Numbers Authority (IANA) under the Internet Engineering Task Force (IETF) arrangement, then in one aspect, adding in the UDP header a Session ID field for identifying the session. The method can be used to identify the frames of the Real-time Transport Protocol (RTP) hop by hop during the packet's transmission, and to provide priority for real-time traffic transport so as to provide a QoS guarantee for real-time traffic even in the case of dramatically increasing network traffic.