This Recommendation describes the service scenarios@ functional requirements and reference model for visual surveillance system interworking (VSSI)@ based on the requirements and architectures defined by [ITU-T F.743]@ [ITU-T H.626]@ [ITU-T H.626.1] and [ITU-T H.627]. A visual surveillance (VS) service is a telecommunication service focusing on video (and audio) application technology@ which is used to remotely capture multimedia (such as audio@ video@ image and various alarm signals)@ and present them to end users in a friendly manner (including accessibility aspects)@ based on a broadband network with ensured quality@ security and reliability. The VSSI mechanism can achieve cross-system scheduling of multimedia (such as video@ audio and image) and enables the resource and data sharing of different visual surveillance systems (VSSs).