Strategies for optical transport network recovery under epidemic network failures

The current trend in deploying automatic control plane solutions for increased flexibility in the optical transport layer leads to numerous advantages for both the operators and the customers, but also pose challenges related to the stability of the network and its ability to operate in a robust manner under different failure scenarios. This work evaluates two rerouting strategies and proposes four policies for failure handling in a connection-oriented optical transport network, under generalized multiprotocol label switching control plane. The performance of the strategies and the policies are evaluated under multiple correlated large-scale failures. We employ the Susceptible–Infected–Disabled epidemic failure spreading model and look into possible trade-offs between resiliency and resource efficiency. Via extensive simulations, we show that source rerouting outperforms on-site rerouting, and that there exist a clear trade-off between policy performance and network resource consumption, which must be addressed by network operators for improved robustness of their transport infrastructures. Applying proactive methods for avoiding areas where epidemic failures spread results in 50 % less connections requiring recovery, which translates in improved quality of service to customers and lower recovery expenses for the network operator.