This paper analyzes the performance of a reliable multicast transport protocol and discusses experimental test results. The Reliable Multicast Transport Protocol has been proposed to support “reliable” information delivery from a server to thousands of receivers over unreliable networks via IP-multicast. The protocol provides high-performance for most receivers through the advantage of IP multicast while also supporting temporarily unavailable or performance impaired receivers. Its applicability to large scale delivery is examined using an experimental network and the backoff time algorithm which avoids ACK implosion. The two types of flow control with the protocol are also examined. Separate retransmission is used to offset the local performance decline limited to a small number of receivers. Monitor-based rate control is used to offset the global performance declines due to causes such as network congestion.