Tencent Swisscom Huawei Huawei Huawei The generation of BGP adj-rib-in, local-rib or adj-rib-out comes from BGP route exchange and route policy processing. BGP Monitoring Protocol (BMP) provides the monitoring of BGP adj-rib-in [RFC7854], BGP local-rib [RFC9069] and BGP adj-rib-out [RFC8671]. By monitoring these BGP RIB's the full state of the network is visible, but how route-policies affect the route propagation or changes BGP attributes is still not. This document describes a method of using BMP to record the trace data on how BGP routes are (not) changed under the process of route policies.