Permanent Establishment determines source state taxation of business profits, distinct from the broader concept of business connection. The concept of Permanent Establishment determines source state taxing rights where an enterprise carries on business through a fixed place of business or via an agent who habitually concludes contracts; preparatory or auxiliary activities are excluded unless combined to form a cohesive operation or linked to a related enterprise's PE. The UN Model broadens the OECD approach by lowering thresholds for construction and recognizing service and insurance PEs. Indian law uses the broader concept of Business Connection, which can exist independently of PE.