A Broadband Network Gateway (BNG) in a fixed wireline access network is an Ethernet-centric IP edge router and the aggregation point for subscriber traffic. Control and User Plane Separation (CUPS) for such a BNG improves flexibility and scalability but requires various communication between the User Plane (UP) and the Control Plane (CP). China Mobile, Huawei Technologies, and ZTE have developed a simple CUPS control channel protocol to support such communication: the Simple Control and User Plane Separation Protocol (S-CUSP). S-CUSP is defined in this document.
This document is not an IETF standard and does not have IETF consensus. S-CUSP is presented here to make its specification conveniently available to the Internet community to enable diagnosis and interoperability.