Algorithms for server placement in multiple-description-based media streaming

Multiple description coding (MDC) has emerged as a powerful technique for reliable real-time communications over lossy packet networks. In its basic form, it involves encoding media into m substreams that are routed independently towards a given destination. Each substream can be decoded independently and with every successful reception of a substream, the overall quality of the decoded signal is improved. In this paper, we consider the problem of placing a set of servers in the network such that a desired QoS can be provided to a community of clients that request MDC coded traffic. Specifically, we consider the server placement (SP) problem where the goal is to identify the "optimal" server positions and associated set of client-server paths such that if MDC content is placed at these servers a cost function that is a linear combination of average delay and path disjointness is minimized. We propose an MILP formulation and a highly efficient heuristic to solve the SP problem. Simulations are conducted to evaluate the performance of the proposed algorithm and compare it with the optimal solution obtained by using the MILP solution.