Mathematical Programming for Joint Protection/Restoration of IP over DWDM Networks

A novel joint multilayer restoration scheme for IP-over-DWDM networks is proposed, where the restoration algorithm manages network resources from both the IP layer and the optical layer in a synergistic manner. Since IP router ports are typically more expensive than optical switch ports, the essence of the approach is to attempt to reuse IP service ports or the service wavelengths associated with optical switch ports for restoration rather than reserve additional standby IP ports exclusively for network recovery. This can be done when there are concerted actions between the IP and optical layers. Since in our approach network recovery is performed by joint actions in the IP and optical layers, we compare this to an approach where a node failure is recovered in the IP layer alone with no assistance from the optical layer.