How are partitions and calling search spaces in Cisco Unity Connection different from partitions and calling search spaces in Cisco Unified Communications Manager?

This is factually incorrect - calling search spaces in Unity Connection explicitly contain lists of partitions, which is the foundation of their access control function.

This reverses the relationship; objects are placed into partitions, and calling search spaces reference those partitions - partitions do not contain calling search spaces.

Partitions and calling search spaces are actively used in Unity Connection and are central to its access control and directory visibility architecture.

Cisco Unity Connection adopted the same partition and calling search space model used in Cisco Unified Communications Manager, where objects such as users and call handlers are assigned to partitions, and a CSS defines an ordered list of partitions a caller is permitted to search or reach. This design consistency means administrators experienced with CUCM can apply the same logical framework directly in Unity Connection. The model governs directory visibility, transfer access, and call routing in both products using identical hierarchical logic.

Both partitions and calling search spaces are required in Unity Connection; using only partitions without a CSS would provide no mechanism for specifying which partitions a given caller or handler is permitted to access.