Dynamic Restoration Assessment in Partially Upgraded Networks from the C to the C+L bands

The attraction of new services and applications over the Internet makes it critical for the network operators to increase the capacity of optical networks. To this end, multi-band elastic optical networks (MB-EON) are at the forefront of this capacity improvement for the short and medium term. These networks employ additional spectrum bands from the optical fiber other than the C (conventional) band. Due to the current availability of L-band erbium doped fiber amplifiers (EDFAs), lighting up the L-band of already installed fibers is considered as a pragmatic approach. However, network operators envision a soft migration from current C-band to fully upgraded C+L-bands networks in order to distribute the high cost of equipping all fibers and nodes of a network with multi-band devices over several years. Therefore, it is essential to propose solutions for scenarios where just a subset of network elements has been upgraded, i.e., to consider a hybrid C/C+L optical network rather than a fully upgraded one. As using the L-band besides the C-band doubles the network capacity, the management of the potential fiber failures is an important factor. In this work, the focus is set on the evaluation of the network performance, when considering different levels of partial migration, and comparing the use of dynamic restoration versus dedicated protection. Simulation results demonstrate that the usage of dynamic restoration, mainly in the middle stages of migration towards a fully upgraded network can remarkably boost the supported traffic load compared to the use of dedicated protection.