Before revision:  Thus, finding the right resource allocation requires striking a careful balance between blocking and costs, a problem which is further complicated by the stochastic nature of the network. Although certain classes of queueing networks allow for a closed form optimisation problem to be formulated and solved, such results only exist for highly stylised networks, and in particularly do not allow for blocking. Another class of current solution methods is simulation-based optimisation, where the resource allocation is evaluated and updated using simulation.
After revision:  Thus, finding the right resource allocation requires striking a careful balance between blocking and costs, a problem which is further complicated by the stochastic nature of the system. Owing to the complexity of the system there are no analytical results available that formulate and solve the relevant optimization problem in closed form. Traditional simulation-based optimisation, where the resource allocation is evaluated and updated using simulation.