This paper proposes a managed IP multicast platform that enables IP multicast services to be used for business. Nowadays, many business applications have switched from traditional network platforms to the IP platform. Among these applications, one-to-many or many-to -many types of applications are especially essential to business users. These applications may use IP Multicasting for transmitting data to many users. However, for business applications, it is difficult to use the present IP Multicast services, because they lack many requirements for business usage. The requirements are address management, authentication, time management, and guaranteed throughput. To satisfy the business users, we made the design of a managed IP multicast platform that will meet these requirements. Our platform, which separates the routing control layer and the packet forwarding layer, is called GMN-CL (Connection Technologies for Global Mega-media Network). The routing control layer manages routing information and controls network routing centrally, so it can understand the whole network situation and perform efficient routing. The packet forwarding layer can concentrate completely on forwarding, so the forwarding speed and copying speed is higher than when using routers. We have implemented our design of a managed IP multicast platform over GMN-CL. This paper reports the system design, implementation, and evaluation.