Close-By Plant Assignment 
You use this function to create assignments between your own plant and other plants.
When you execute a search in the Enhanced Material Search function, it is done within the context of your own plant. It is also possible to extend that search beyond that plant to other plants. Close-by plants represent the list of predefined plants, for example, in the neighborhood of your own plant, or the list of plants for which employees at your own plant are usually interested in seeing stock levels and prices.
The close-by plant assignment application allows you to manually maintain assignments between plants. The close-by plant assignment screen is split into two windows. The source window lists every plant in the system, whereas the target window lists every plant in addition to all the close-by plant assignments you create.
Prerequisites
You can define your own display hierarchies for your close-by plant assignment application. Hierarchies group plants together in a logical business context (for example, by geographical location). You can define your own hierarchies in Customizing by choosing 
Logistics
– General 
Material Master Enhanced Material Search with Material Creation Define Hierarchy for Close-By Plants 
Features
Close-by plant assignments are created in the context of an application. For example, you can create a set of close-by plants for the Sales Order application, and an entirely different set for the Procurement application.
You can prioritize close-by plants for a given plant. When you execute a search in the Enhanced Material Search function, the system sorts close-by plants according to your prioritization. The priority assignment is entirely relative; it can represent proximity to the local plant, the physical size of the plant, or whatever you decide.
Activities
Access the Close-by Plant function in the SAP Easy Access menu by choosing Logistics Materials Management Material Master Other Additional Functions
for Material Close-By Plants (transaction WSD_CBP).
To create a close-by plant assignment, select a source plant, a target plant, and choose Assign. The source plant is then designated to be “close by” the target plant. You can also bidirectionally assign close-by plants, in which case two assignments are created (from source to target and target to source). Close-by plant assignments are usually done by a plant manager for their own plant.