On the cross-layer restoration to address packet layer failures in P2MP-TRX-based WSONs

Digital subcarrier multiplexing (DSCM)-based coherent point-to-multipoint transceivers (P2MP-TRXs) are promising for addressing the shift in traffic patterns from point-to-point (P2P) to hub-and-spoke (H&S), and their application in wavelength-switched optical networks (WSONs) can potentially offer enhanced flexibility and efficiency in handling the mixed traffic therein. In this paper, we study how to secure the survivability of P2MP-TRX-based WSONs against packet layer failures with cross-layer restoration (CLR). By analyzing the unique features of P2MP-TRXs, we first design three CLR strategies to restore the traffic affected by packet layer failure(s) and then formulate an integer linear programming (ILP) model to leverage them for cost-effective CLR, i.e., minimizing the cost introduced during the CLR process. Next, we propose a time-efficient heuristic, namely, hHAG-DP, which leverages hybrid dynamic programming (DP) and a hierarchical auxiliary graph (HAG) to find cost-effective CLR schemes quickly. Extensive simulations confirm the effectiveness of our proposals.