Segmentation Strategy 
To efficiently plan your requirement, it is necessary to fulfill newly arising requirement (such as sales orders) with existing or future stock (for example, purchase requisition). If you have defined segments for your material, you can assign the stock to the requirement using these segments. Segmentation strategy determines how requirement segments are assigned to stock segments. This kind of assignment takes place during available-to-promise (ATP) check and material requirements planning (MRP).
Segmentation strategy is also important for the following requirement elements and stock elements:
For externally procured materials during planning run. For example, during the creation of purchase requisitions.
For the components of materials, i.e., the dependent requirements and the fulfillment of those requirements.
For consumption of planned independent requirements using the actual customer requirements during the planning run.
Segmentation strategies are defined in the Customizing for Define Segmentation Strategies under 
SAP Implementation Guide 
Logistics - General Segmentation 
Note
You have defined segmentation relevant characteristics using Master Data Characteristics Management (transaction CT04). For more information, see Maintain Segmentation Relevance for Functions.
Features
Assignment of Stock or Requirement Segments
If you have assigned segments to a material, you can assign stock to the requirements using segmentation. The assignment of stock to requirements takes place during the planning run. The system determines which requirement segment is covered by which stock segment.
You determine the following sequence for your segmentation using your segmentation strategy:
You receive a requirement, such as a sales order. For example, the requirement belongs to customer segment Wholesale and is of quality Quality 1.
Using segmentation strategy, you define that this customer will receive the requested segment first, if you have the segment in stock.
If the requested segment is not in stock, you decide that the customer will receive available stock segment in the next level.
It is not mandatory to attach a segmentation structure or a segmentation strategy to a material.
A segmentation strategy can have multiple requirement segments but can be assigned to only one blank stock segment. Such segmentation strategies are identified by Scope in Segmentation Strategy. Scope indicates if the segmentation strategy only contains requirement segments or both requirement and stock segments.
Deletion of Segmentation Values
You can delete segmentation values for segmentation combinations. However, if you wish to delete multiple segmentation values, you can use the transaction SE38 to execute the report program SGT_DELETE_CATS.