A network engineering framework for upgrading service availability of optical mesh networks

• A general framework for network engineering of upgrading service availability.
• Optimization by integer linear programming (ILP).
• Two heuristic methods for calculating the sequence of installing protection links.
• Three common routing algorithms are used to evaluate the proposed NE framework.

We present a network engineering process to improve service availability of optical mesh networks by employing protection links. In the existing optical mesh networks, high service availability is usually achieved by network planning with an appropriate routing and wavelength assignment (RWA) algorithm. However, network planning cannot provide upgrade paths for unpredictable new demands. To meet the requirements of practical operations, a network engineering process is developed to improve service availability in an upgrade manner. A model of integer linear programming (ILP) is proposed to minimize the upgrade cost. In addition, heuristic methods for calculating the sequence of incrementally installing protection links are presented. Our experimental results show that the proposed network engineering process can improve service availability with low cost. They also demonstrate that the network engineering process can exclude the necessity of a routing algorithm optimized for service availability because such an algorithm usually results in higher upgrade cost than those optimized for path length or link load.