Supplier Release Scheduling (SRS) or Vendor Release Scheduling (VRS) can be used as part of MRP plan where planning and location information about items are shared real time with vendor or supplier so that vendors can replenish the items when needed. Examples of industries using this would commonly include those importing global food stuffs, harvested crops, Industries sourcing goods with very long lead times. Industries with limited storage capability could use this for long lead-time large Configured project part scheduling. SRS will process Order (O), Order & Expedite (B), & Increase Order Quantity (G) message types only.
The see Understanding Supplier Release Scheduling (SRS) (Doc ID 637829.1) for detailed insight on this functionality.