Abstract : The "Light-weight On-demand Ad-hoc Distance-vector Routing Protocol-Next Generation" (LOADng) is a simple, yet e cient and flexible routing protocol, specifically designed for use in lossy networks with constrained devices. A reactive protocol, LOADng-as a basic mode of operation-o↵ers discovery and maintenance of hop-by-hop routes and imposes a state in intermediate routers proportional to the number of tra c paths served by that intermediate router. This paper o↵ers an extension to LOADng, denoted LOADng-PA (Path Accumulation). LOADng-PA is designed with the motivation of requiring even less state in each intermediate router, and with that state being independent on the number of concurrent tra c flows carried. Another motivation the design of LOADng-PA is one of monitoring and managing networks: providing more detailed topological visibility of tra c paths through the network, for either tra c or network engineering purposes.