A growing interest in third generation wireless IP network and service technologies, push up the demand on IPv6 transition. Most of these services require mobility, multicast and multimedia service supports. However, the transition to such a NG IP networks and services is slowed down because of the richness and complexity of the applications and the integration of legacy systems. Existing IETF and academic proposals permit to solve several transition problems but they don’t cope with the multimedia or wireless aspects of some next generation IP services. In the other hand, most transition solutions are limited to LANs and couldn’t scale well. Therefore, this article describes the architecture and the implementation of an integrated multi-functional IP gateway for IPv4/IPv6 network transition with multimedia, multicast and mobility service management. This gateway, named M3G, has been partially implemented and validated on a Linux-based testbed with MPEG4 video streaming application...