Coordination of production/distribution networks with unbalanced leadtimes

We investigate multiproduct, multilocation production/distribution networks with deterministic, stationary demands. Most research on such systems assumes zero leadtime. Methods using fixed reorder intervals that are power-of-two multiples of a base planning period have proved to be very successful for such systems. The same methods apply to networks with positive leadtimes, provided the leadtimes are balanced in a specific sense. We explore networks with general, unbalanced leadtimes. A key result is a lower bound on the cost of any feasible policy. Other results concern policy heuristics and their performance. For a large class of networks, we construct a policy whose cost is within 45% of the lower bound. For general networks, the performance guarantee is 1.02√(1 + η), where η is a number dependent on the network topology only. In general, the best performance bound is obtained by systematically reducing the order intervals derived from the corresponding zero-leadtime system.