Reliable multicast requires that all packets are safely delivered to the destinations. Such communication patterns are in-tensively used in the so-called grid computing infrastructure where many computing resources are spread over the Internet to offer to the users the access to a huge amount of computational power. However, meeting the objectives of reliable multicast is not an easy task and this paper presents active solutions that aim to reduce the end-to-end latency and to increase the achievable throughput of reliable multicast protocols for grid computing over the Internet. More specifically, the performances of several active mechanisms such as NACK aggregation and subcasting are investigated.