k-connected network partitioning under shared risk link groups

Partitioning a large network into a connected hierarchy is a proven technique for scalability and manageability. Although a significant body of work is devoted to this area of interest, a reference to survivable hierarchical networks where each partition remains k-connected is missing (k ≥ 2). A k-connected partition ensures functional network organization even after any k - 1 failures occur. In optical networks, a failure of a physical component (e.g., a cable or line-card) disrupts multiple logical links that share the component. Such a shared risk link group (SRLG) failure is more common than a single link or node failure in the logical topology. Hence, we study the significance of a k-SRLG-connected (kSC) partitioning problem for optical networks. For a given network, we show that finding 2-SRLG-connected (2SC) partitioning, the simplest case, is NP-complete. We provide mathematical formulations and propose a distributed-scalable heuristic solution. We also solve 2SC partitioning with flexible mapping onto the physical topology, where lightpaths can be added to guarantee a solution. Simulation results verify that the kSC partitioning scheme performs better than traditional 1-connected partitioning schemes with regard to system survivability, stability, and repartitioning overhead.