HiTi graph model–based routing algorithm for fast path recovery in large-scale optical networks

The rapid growth of traffic demand together with edge-oriented deployments has driven the extension of core bearer capabilities toward the edge to accommodate increasingly fine-grained service demands, thereby significantly enlarging the network scale. In such large-scale networks, fiber link failures are more likely to occur, and a single fiber cut may affect thousands of services. Consequently, achieving rapid path recovery has become a critical challenge, as traditional Dijkstra searches over vast candidate sets are highly inefficient. We propose a HiTi graph model–based fast routing algorithm for optical networks (HOFR). By leveraging the multi-layer graph partitioning mechanism of the HiTi graph model, HOFR swiftly reduces the search space for path computation while strictly adhering to O/E/O regeneration constraints. Simulation results demonstrate that the proposed HOFR algorithm significantly reduces post-failure rerouting time compared with the traditional Dijkstra algorithm on a real-world operator network topology with 500 nodes, while achieving recovery path lengths comparable to those of shortest-path solutions.