The DRP process is managed by a source and destination logic otherwise known as a bill of distribution. The destination is the ship from (stock) location to either another location or to the customer. The source is where the supply for the destination is received from. This relationship is shown in the selection interface as follows:

1. The location of the item is defined in the location column. This is where the inventory is maintained for a give item / location.
2. The locations may be filtered by selecting one or more locations in the drop down selection filter.
3. The supplier of a given item/location is defined in the supplier column
4. A Supplier with an * after its name means the supplier is a location.
5. When the source and destination is the same, the item is manufactured in the location. The replenishment orders are handled by production orders and the lead time is either the production time or order time.
6. If the source and destination locations are different, the location receives its inventory via a transfer order from the source location. The time required to transfer the item is defined by the transfer time lead time.
7. When the supplier does not have an * and there is a name in the column, its source is a supplier and managed via a purchase order. The lead time to purchase is the Lead Time or Order Lead Time if a Transfer (transit) Time is applied.
8. An "unknown" supplier is undefined and either is manufactured in the location or should be corrected if the item location requires a transfer order or a purchase order.

The Distribution Requirement Plan is part of the Requirement Planning process. The process is managed as follows:

1. It starts with a forecasts and/or customer orders in the ship from location which we also call the destination location.
2. The forecast and customer orders are translated to a requirement plan where suggested orders are generated to maintain inventory based on the item/locations inventory attributes.
3. These requirements are then translated from the Destination location to its source as defined in the Distribution Panel. The Distribution Panel is opened by hovering your cursor over the word "Distribution Panel."
4. The translation of the requirements from the destination to the source is done so by the transfer lead time (read the article DRP Lead Time Logic to learn more). The transfer lead time is the second lead time value in the image below.

Note: The graph in the image below is hidden via the graph button in tool bar.

1. The requirements from the destination are passed to the source with a ship date at the source offset by the transfer time. These requirements are placed in the dependent demand column of the source location. Placing the cursor over any of the orders in the Dependent Demand column shows the orders and where they are coming from.
2. The history in the source is the sum of the sources independent demand locations.