as you probably know, there is no functionality in SAP ERP to perform a multi-level availability check throughout your supply chain. If you have a network of multiple DCs and manufacturing plants and a customer order needs to check where in the network there is inventory, then the ERP check can look from a specific DC back to the source for that DC… and no further.
The Global ATP Check in APO can do it, but if you have no APO, you have to resort to other means.
A valid solution to the problem is using the special procurement indicator ‘Direct Production’. Assume you have a DC in Ohio, a Warehouse in Texas and the manufacturing plant also in Texas. If the warehouse is close enough to the plant, you don’t need stock transport orders to move the product to the warehouse but you can use direct production. That means that the Production Order is visible in the Warehouse. Now if the DC in Ohio receives a customer order asking for more than what is in inventory, the availability check looks in the warehouse in Texas and if there is no inventory either, it can check whether a future production order would provide enough quantity to fulfill the order in Ohio.
Note that this only works because the production order is visible in the Warehouse’s MD04 through direct production. The availability check can not look into the manufacturing plant – it stops at the warehouse. This solution is not nearly as sophisticated as the Global ATP in APO, but, at least it gives you one more entity for the scope of check