Each system in the system landscape must be assigned a unique key block range. This range is used to ensure that when a business object is transported to another system in the system landscape, the primary keys and other unique ids used by the entities that make up the business object do not clash with those of entities already present on the target system. This subsection provides information on configuring systems with a unique key block range. In advance of reading this subsection, the chapter on Unique IDs in the Cúram Server Developer Guide should be read - it provides details of how unique IDs are used within the application.