Multicast is a one-To-many communication model that is important for video streaming like IPTV. However, multicast does not guarantee the reliability of data transfer, and packet loss beyond the performance of error correction mechanism introduce significant degradation of the quality of Multicast streaming. Monitoring quality of multicast streaming is difficult because a) generally intermediate multicast routers and switches do not maintain the fine-grained state about multicast flow and b) sampling QoS statistics from destination clients introduces significant operational overhead. Therefore, it is difficult to properly locate where packet losses happen and how severe they are. This paper proposes selective packet tagging based monitoring (SPTM) mechanism to detect and locate packet losses in real-Time using a packet tagging technique in Software-Defined Network(SDN). The proposed system also re-calculates the Multicast Delivery Tree(MDT) upon the detection of packet losses in the tree links. The evaluation results show the feasibility of the proposed approach to detect, locate as well as recover the MDTs from the packet loss. © 2019 Copyright held by the owner/author(s).