1. A method for planning optimal locations of a plurality of servers in a video-on-demand network of a tree topology and optimal assignment of a plurality of programs to each of the servers for requested demands at each node, comprising: minimizing a sum of costs of installed servers, costs of assigned programs, and costs of link bandwidths required to broadcast the programs over links of the network while satisfying the demands for a plurality of programs at a plurality of nodes as specified by a CONDIS model for the requested demands time invariant set of demands using dynamic programming optimization method specified by DPM-CONDIS to determine optimal locations of the plurality of servers and optimal assignment of the plurality of programs at each of the servers where said method uses dynamic programming equations specified by DPE-CONDIS.