This paper presents a novel technique for providing non-stop IP-based television broadcasting service on ISP's multicast network. Although ISP network is highly available in terms of both data link and network layers, the recovery time from some network layer trouble may be intolerable to provide broadcasting service. We propose a gateway approach for providing loss-less backup multicast distribution during the recovery operation. The verification results show that our prototype system saves more than one thousand packet losses without any changes in the implementation of servers, network nodes, and customer premises