Signalling aspects of optimized inter-domains point to multipoint paths in Multi Protocol Label Switched networks

We propose a method to compute point to multipoint (P2MP) traffic engineered paths that cross several MPLS domains. It relies on the use of multiple Path Computation Elements (PCEs), in the goal of calculating a P2MP tree along a given tree of domains by using a recursive path computation technique. Indeed, the calculation is started by the PCEs of the destination domains, i.e. those ones that are not connected to any domain downstream and it is continued upstream from PCE to PCE until reaching the P2MP tree source. A PCE should determine the total number of paths downstream and send them to an upstream PCE. This is required in order to ensure that the obtained inter domain P2MP tree is optimized, where the optimization criteria is the minimization of the number of links of the tree. A detailed signaling example is hence highlighted and discussed.