MRP system include: inventory control, bill of material processing, and elementary scheduling. MRP helps organizations to maintain low inventory levels. It is used to plan manufacturing, purchasing and delivering activities.
Material Requiremnts plan and master schedule (MRP) answers two quisitions:
1. How mauch you need to supply (Make/Buy).
2. How much resource Hours needed to produce.
MRP is an unconstrained, and infinite planning engine. this means, if you have a demand (Sales order/Forecast), the planning engine recommend actions to be done based on demand due date only regardless of capacity or material availability, and it gives you exception messages to take action; as a planner; regarding anything that may violate satisfying the demand in that due dates.