ZTE Corp. Apstra, Inc. Google Huawei CMCC Segment Routing (SR) architecture leverages the paradigm of source routing. It can be realized in the Multiprotocol Label Switching (MPLS) network without any change to the data plane. A segment is encoded as an MPLS label, and an ordered list of segments is encoded as a stack of labels. Bidirectional Forwarding Detection (BFD) is expected to monitor any existing path between systems. This document defines how to use Label Switched Path Ping to bootstrap a BFD session, control an SR Policy in the reverse direction of the SR-MPLS tunnel, and applicability of BFD Demand mode in the SR-MPLS domain. Also, the document describes the use of BFD Echo with BFD Control packet payload.