This Recommendation describes the functional requirements of IP-based smart digital audio services. To provide IP-based smart digital audio services over broadcasting networks, there are several functional requirements to be considered: transmission and coding efficiency, bit rates, IP-based transport packaging for interoperability with diverse networks, scheduling, metadata services, and auxiliary services. This Recommendation is Part 2 of a multi-part deliverable composed of 3 parts. Part 2 describes the functional requirements of IP-based smart digital audio services. The other parts are identified below: Part 1: Requirements for IP-based Smart Digital Audio Service; Part 2: Functional requirements for IP-based Smart Digital Audio Service; Part 3: Specifications for IP-based Smart Digital Audio Service;