Recommendation ITU-T H.626.3 defines an architecture of visual surveillance system interworking. A visual surveillance system is deployed as a standalone and fully autonomous system, and the data and resources cannot be shared between different visual surveillance systems. The visual surveillance system interworking mechanism enables communication among the different visual surveillance systems, and this interworking mechanism can realize the cross-system sharing of data and resources. This Recommendation describes the architecture, entities, reference points, service control flows and deployment models for visual surveillance system interworking.