Retransmission-based error control for scalable streaming media systems

Large-scale continuous media (CM) system implementations require scalable servers most likely built from clusters of storage nodes. Across such nodes, random data placement is an attractive alternative to the traditional round-robin striping. One benefit of random placement is that additional nodes can be added with low data-redistribution overhead such that the system remains load balanced. One of the challenges in this environment is the implementation of a retransmission-based error control (RBEC) technique. Because data is randomly placed, a client may not know which server node to ask for a lost packet retransmission. We design and implement three RBEC techniques that utilize the benefits of random data placement in a cluster server environment while enabling a client to efficiently identify the correct server node for lost packet requests. We implement and evaluate our techniques with a one-, two-, four-, and eight-way server cluster and across local and wide-area networks. Our results show the feasibility and effectiveness of our approaches in a real-world environment and also identify one solution as generally superior to the other two.