Optical layer-driven network restoration and redesign for improved fast reroute reliability

Fast Reroute (FRR) is a local restoration mechanism available in Multi-Protocol Label Switching (MPLS). With FRR, data traffic over a failing MPLS-link is swiftly rerouted through a pre-provisioned restoration tunnel. The FRR solution works well so long as the restoration tunnel is not adversely affected by other concurrent failures. Additional protection against this drawback is offered by the lower (optical) layer, which provides restoration lightpaths to replace the failing MPLS-link(s). The optical layer can also provide a second remedy, which consists of redesigning a portion of the MPLS-topology on-the-fly. This paper investigates the reliability improvement that these two optical layer-driven techniques can yield.