Efficient multicast communication provides a good opportunity for scaling bandwidth intensive application. Current multicast routing involves selection of a \emph{core} also known as rendez-vous point through which most of the multicast communication is routed. The purpose of this paper is to study the performance impact of migration techniques. Several studies were performed on heuristics to choose a good core but none of them presents and implements the migration itself. Moreover, by using active networking architecture, we are able to adapt our multicast protocol to the application needs. Indeed, the application may provide the cost function used to evaluate the "quality" of the multicast tree. Experimental results reveal that active multicast routing with migration performs well and uses network resources in a very efficient way.