Multicasting has gained much attention in recent years because it can efficiently utilize network bandwidth and reduce the load at application servers.The shared tree multicast protocol is more preferable due to its good scalability. At the same time

more and more mobile users require to participate in multicast communication. However

current shared tree multicast protocol performs poorly in dynamic/mobile environment. Some proposed protocols-one core migration protocol

improves the performance of shared tree protocol at the expense of large overhead in tree adjustment. This paper presents a new shared tree multicast protocol-dynamic multi-core protocol. This protocol can adjust the multicast tree according to the locations of multicast group membership gradually and thus provide good performance to group members with low cost. Computer simulation and mathematical analysis both show that dynamic multi-core protocol outperforms old shared tree protocol and one core migration protocol.