Core network supported multicast routing protocol for wireless sensor networks Multicast routing protocols improve the network performance by optimising the parameters such as bandwidth, channel utilisation and throughput rate. In wireless sensor network, the primary multicast routing protocol is geographic multicast routing. This study proposes core network supported multicast routing (CNSMR) protocol, a stateful-based distributed multicast routing protocol for sensor networks. The proposed protocol comprises of heterogeneous nodes such as cluster head (CH) nodes, core nodes (CNs) and sensor nodes (SNs). The distinct set of nodes known as CNs have computing, storage and energy resources more than the SNs. CH nodes and CNs form the core network, and CNs with core network and SNs form the core network supported multicast tree. SNs participate in multicast routing supported by the core network and thus save the node energy. Multicast routing in the proposed core network supported multicast trees balance the load in the network and improve the network performance as compared to the existing WSN multicast routing protocols. The proposed CNSMRprotocol is compared with the existing WSN multicast routing protocols such as DCME-MR, Intelligent-MR, H-GMR and OnDemand-MR. Simulation results indicate improvements in delay latency, energy save ratio, throughput rate, end-to-end packet delay, multicast control overhead ratio and packet delivery ratio for the proposed protocol.