scope:

This Recommendation provides the stage 3 specification of the Rt interface. The localization of the Rt interface in the overall resource and admission control function (RACF) architecture is visualized in Figure 1. The functional requirements corresponding to this interface are contained in clause 8.5 of [ITU-T Y.2111] and in [b-ITU-T Q-Sup.51].

The Rt interface protocol operates between the policy decision and the transport control physical elements (Figure 2) of the resource and admission control function (RACF) and is used to control network transport resources required to convey the media flow.

NOTE - Protocols operate between physical entities which are instantiations of corresponding functional entities defined by functional architectures.