A system and method for generating a stochastic model of network traffic demands in a network is disclosed. The system receives information characterizing a network to be modeled, the information including network component data describing the nodes of the network, demand data describing projected traffic demands for the overall network, and weight data describing which nodes contribute relatively more or less to traffic within the network. Using the network information, the system probabilistically allocates the projected traffic demands to the nodes of the network, over multiple trials, to generate a stochastic model of network traffic. In the stochastic model, flows within the network from a source node to a destination node are each associated with a distribution curve of demand that represents the probabilities of different levels of demand that may be required of each of the flows.