Combining Electronic Layer Protection And Pre-Planned Optical Restoration For Improved And Resource-Efficient Reliability

Wavelength Division Multiplexing (WDM) backbone networks carry large volumes of traffic. Even a single network element outage (e.g., a fiber, a site, a port) can cause significant traffic loss due to the ensuing disruption of many active data flows. Pre-planned restoration schemes ensure that spare resources are readily available in the network for promptly provisioning backup paths that can mitigate the disruption caused by such outages. In this study, the authors investigate the efficiency of a pre-planned restoration scheme applied to a two-layer network, consisting of Multiprotocol Label Switching (MPLS) over WDM. In this architecture, the MPLS layer implements a fast reroute (FRR) protection scheme, while the optical layer underneath implements pre-planned restoration of lightpaths. This architecture is increasingly gaining traction due to the reduced resource overhead that it requires to offer extra reliability against multiple failures.