Tsinghua University Zhongguancun Laboratory Zhongguancun Laboratory This document specifies a BGP Flow Specification extension that conveys per-route feedback binding for a FlowSpec route using the BGP Extended Community attribute. The proposed mechanism introduces a single Feedback Action, encoded as a Generic Transitive Extended Community, which enables downstream routers to report telemetry information or operational events associated with a FlowSpec rule. The Feedback Action carries parameters including a Feedback Identifier (FID), a window exponent (WINC) that defines the periodic aggregation interval, an event flag, and a scope selector to control where feedback is generated. These parameters are attached to the FlowSpec route and are propagated across AS boundaries unchanged. This document focuses on the signaling aspect; a companion document may define how feedback information is exported as part of a network telemetry framework (e.g., leveraging the BGP Monitoring Protocol (BMP)) or equivalent mechanisms to report periodic and event-driven feedback keyed by the FID.