BSR-Based Weak Survivability Traffic Grooming in IP over Multi-Core Fiber Elastic Optical Networks with Crosstalk-Aware Optimization

In multi-core fiber elastic optical networks (MCF-EONs), a single fiber-link failure can disrupt traffic across every core of the failed fiber. This paper studies bandwidth-squeezed restoration (BSR) in IP over MCF-EON, where an admitted service must recover a demand-specific fraction of its original bandwidth. Four policy-matched mechanisms are considered: single-route IP-BSR, single-path optical SP-BSR, optical MP-BSR, and cross-layer Joint-MP-BSR. Joint-MP-BSR retains a complete IP-BSR branch and a flexible branch that assigns available bandwidth to one surviving IP route before using end-to-end optical multipath for the exact residual. A failure-scenario-indexed candidate-configuration MILP supplies an exact benchmark over an enumerated candidate set with core-slot collision, sharing, and cumulative inter-core-crosstalk constraints. In 30 paired NSFNET online-provisioning replications, Joint-MP-BSR reduces protected-service blocking by 0.0617 relative to IP-BSR (95% CI, 0.0308–0.0926) and by 0.1250 relative to MP-BSR (0.0632–0.1868); MP-BSR improves on SP-BSR by 0.2633 (0.1713–0.3553). On COST239, Joint-MP-BSR improves on IP-BSR, whereas its difference from MP-BSR is not statistically significant. In a separate 30-instance frozen N6S8 benchmark, heuristic/MILP admission totals are 112/112 for IP-BSR, 59/59 for MP-BSR, and 114/114 for Joint-MP-BSR. Joint’s conditional Tx/Rx overhead is 10.717% after the two admission objectives tie, exposing a resource refinement opportunity. These results support IP-first multipath BSR within the evaluated candidate, traffic, and physical-layer settings rather than universal or large-network dominance.