This Recommendation defines the functional requirements of IP-based switched digital video (SDV) using data over cable service interface specifications (DOCSIS). The functionalities described in this Recommendation are defined according to the requirements of cable television system operators. The IP-based SDV is the service mechanism for providing interfaces and functionalities to enable cable television system operators to offer quality of service (QoS)- guaranteed broadcasting. SDV is a service mechanism for distributing digital video via RF-based cable networks; an IP-based SDV is a support SDV function which works via IP-based cable networks.