MPLS On-Path Telemetry Network Action Flag for OAM

This document describes the postcard-based on-path telemetry with packet marking (PBT-M) using an MPLS Network Actions (MNA) flag to support OAM in MPLS networks. The scheme uses a single bit in the MNA header opcode dedicated for the flag-based actions. The document provides the solutions to address the requirements for applying PBT-M in MPLS networks.