Dynamic multi-layer service-provisioning framework operating with reduced performance margins

Abstract

The need to maximize the return on investment in optical transport networks (OTNs) drives network operators to pursue different strategies to increase the capacity per optical channel deployed with the aim of reducing the overall network cost. Traditionally, optical channels have been provisioned with large optical margins to account for worst-case performance degradation over the channel lifetime, which may limit the use of higher-order modulation formats. However, the adoption of flexible-rate line interfaces and progress in control-plane solutions and monitoring-performance platforms will enable more flexibility. In particular, real-time monitoring of the current performance, and forecasting its evolution, can be combined with an optimized multi-layer framework allowing the deployment of reduced margins while mitigating the impact of events where the optical channel time-to-live becomes shorter than that of the client demands it carries. This paper investigates the resulting multi-layer optimization problem that arises when exploiting the joint availability of accurate performance-monitoring platforms and OTN switching technology. In detail, it proposes a novel multi-period design framework based on an integer linear programing model to optimize the provisioning of optical channels with low margins while proactively diverting traffic demands from optical channels reaching the minimum performance level. Simulation results on two reference transport networks highlight that the proposed framework can reduce the number of line interfaces required when compared to existing provisioning schemes while minimizing the number of rerouting events.