Abstract. End System Multicasting (ESM) is fast becoming a feasible alternative to IP multicasting. ESM approaches can be broadly classified into two main categories: (i) Tree first approaches, where an overlay tree is constructed on the physical network, (ii) Mesh first approaches, where a mesh is constructed on the physical network and then a tree is created on the constructed mesh. In this paper, we propose a generic Mesh Tree Interaction (MTI) mechanism, which combines the management efficiency of the mesh first approaches and the performance benefits of the tree first approaches. To achieve this, MTI uses the concept of mesh and enables interactions between the mesh and the underlying multicast tree. Our simulation studies show that MTI results in significant improvement in the quality (average delay metric) of the multicast tree.