As a first step, we should be able to split a demand into 2 demands if the PCE fails in finding a path. We can imagine a simple process that considers that 2 network ports available on the same switch, or 2 network ports available on a regen could be seen as a simple bypass, This means that if we find a path with in the midle such a bypass, we could split the demands into 2 : the 1st starting in A end ending in an intermediate point, and the 2nd starting from the same intermediate point to the Zend. This 2 demands will be handled internally and transparently to the user (if we find a way to provide an information about the fact it is splitted into 2 and that a regenator is beeing used. Only the case of the regen will be considerd in a first step.