RTCPn

RTCPn is a term occasionally encountered in academic literature and vendor documentation to denote an experimental or forthcoming extension to the Real-Time Control Protocol (RTCP), the control plane protocol paired with the Real-Time Transport Protocol (RTP). There is no formal IETF standard named RTCPn, and interoperability with standard RTCP implementations cannot be assumed. RTCP itself, defined in RFC 3550 and supplemented by related documents such as RTCP XR (Extended Reports), provides mechanisms for monitoring transmission statistics, quality of service, and participant information. Typical RTCP functionality includes sender and receiver reports that convey packet counts, jitter, and timing information, as well as source descriptions (CNAMEs) to identify participants. RTCP XR defines extended reporting blocks for more detailed QoS diagnostics.

If present in literature, RTCPn would be understood as an extension intended to augment RTCP with additional feedback channels, more granular QoS metrics, or scalable reporting for large-scale or multi-channel deployments. Potential goals of RTCPn proposals include finer-grained reception quality feedback, enhanced control for adaptive streaming, and improved support for multicast or many-to-many sessions. However, since RTCPn is not standardized, implementations are likely proprietary or experimental, and real-world interoperability remains limited. When encountering RTCPn in documentation, it should be treated as non-normative or speculative until a formal specification is published.

See also: Real-Time Transport Protocol, RTCP XR, QoS in RTP.