TMRCC: a congestion control mechanism for tree-based many-to-many reliable multicast protocols

Congestion control is a key task in reliable multicast along with error control. However, existing tree-based congestion control schemes such as MTCP[11] and TRAMCC[3] are designed for one-to-many reliable multicast and have some drawbacks when they are used for many-to-many reliable multicast. We propose an efficient congestion control mechanism, TMRCC, for tree-based many-to-many reliable multicast protocols. The proposed scheme is based on the congestion windowing mechanism and a rate controller is used in addition. The feedback for error recovery is exploited for congestion control as well to minimize the overhead at the receivers. The ACK timer and the NACK timers are set dynamically reflecting the network condition changes. The rate regulation algorithm in the proposed scheme is designed to help the flows sharing the same link to achieve the fair share quickly. The performance of the proposed scheme is evaluated using ns-2 [2]. The simulation results show that the proposed scheme outperforms TRAMCC in terms of intra-session fairness and shows good level of responsiveness, TCP-friendliness, and scalability.