Recommendation ITU-T Q.3304.1v2 provides the Stage 3 technical specifications for a protocol variant which uses the common open policy service (COPS) (described in IETF RFC 2748) to satisfy the requirements for information transfer across the Rc reference point, as defined in clause 9.3 of Recommendation ITU‑T Y.2111. This protocol allows a transport resource control physical entity (TRC-PE) to collect network topology and resource status information from elements of an access or a core network.