A computer system that uses MRP techniques to manage the entire distribution network and to link it with manufacturing planning and control. The function of determining the need to replenish inventory at branch warehouses over a forward time period. A time-phased order point approach is used where planned orders at branch warehouse level are exploded via MRP logic to become gross requirements on the supplying source enabling the translation of inventory plans into material flows. In the case of multi-level distribution networks, this explosion process can continue down through the various levels of regional warehouses, master warehouse, factory warehouse etc and become input to the master production schedule.