Because one MPLS label only identifies one single flow on a link between two MPLS routers, information related to one MPLS label is exchanged only between (physically and logically) neighbour routers. In other words, MPLS label have a link-local significance on which two neighbour routers have previously agreed on. It is therefore not a trivial task for a network operator to know where a flow is going as it implies to retreive the MPLS labels mappings on each hops in order to get a complete view of end-to-end LSP paths. This taks is even harder when it comes to get the MPLS label mappings over time in a purpose of monitoring and/or troubleshooting network services. This document thus defines a new method to monitor MPLS label mappings that collects and stores MPLS labels mapping information so as to offer to one IP/MPLS network operator a reliable and clear view of its network LSPs end-to-end establishment over time while minimising the impact on network convergence and router CPU.