Two-layer restoration scheme for IP over optical networks with MPLS

Wavelength division multiplexing (WDM) based IP networks will provide capacity for the explosive growth in IP traffic. Network reliability gains importance with the huge volume of traffic carried by such IP-over-WDM networks. Providing survivability at the optical layer is inherently attractive, but raises many questions and challenges, given similar mechanisms already exist at IP layer. The emergence of MPLS and its extension, MPλS, opens up new possibilities for developing simple integrated protection/restoration schemes that can be coordinated at both the IP and optical layers. This paper first presents an overview of existing MPLS/MPλS recovery mechanisms. Then we propose a joint two-layer recovery scheme for IP-centric WDM based optical networks where the optical layer will take the recovery actions first and subsequently the upper IP layer initiates its own recovery mechanism, if the optical layer does not restore all affected services. A simulation-based analysis shows the benefits of the proposed two-layer recovery scheme compared to the single layer recovery schemes.