Provided is a management-system for use in a network environment including a first and second IP networks and a transport network which connects the first and second IP networks. The management system includes: a converter for optimizing a path in an IP-domain via a first algorithm and for converting IP-traffic-signals into transport-traffic-signals; and an optimiser which optimizes a topology that overlays the transport network by optimizing channels in the transport-network according to at least one second algorithm. The first algorithm is an IP multi protocol label switching routing optimization algorithm. The second algorithm is an algorithm based on a plurality of constraints and objectives such as a flow conservation constraint, logical link capacity constraint, optical router port constraint, wavelength cost objective, optical router port occupation objective, advertised link number objective, spare capacity objective, wavelength re-use benefit objective and optical service level agreement constraint.