With network virtualization, the physical infrastructure can be partitioned into multiple parallel virtual networks for sharing purposes. However, different transport technologies or quality of service (QoS) levels may impact both the requested amount of resources and the characteristics of different virtual instances that can be built on top of a single physical infrastructure. In this paper we propose a novel mixed integer linear programming (MILP) formulation for different schemes of protection in scenarios where multiple virtual topologies run over an elastic optical network. The proposed MILP formulation uses the concept of bandwidth squeezing to guarantee a minimum bandwidth for surviving virtual topologies. It achieves a high level of survivability for traffic that is subject to a different committed service profile for each virtual topology. Case studies are carried out in order to analyze the basic properties of the formulation in small networks, and three heuristics are proposed for larger networks.

Wavelength conversion capability has been shown to significantly improve the blocking performance of all-optical networks. In order to transport payloads that may be of different bit-rates and modulation formats, a transparent wavelength conversion method is desirable. Recently, parametric wavelength converters, that are capable of multi-channel wavelength conversion for heterogeneous optical services, have been experimentally demonstrated for optical circuits. In this letter, we analyse the performance of an asynchronous optical packet-switch (OPS) architecture that exploits such devices. A sensitivity analysis of the number of converters, as a function of the main switch design parameters, demonstrate a significant reduction in the number of converters when compared with architectures employing single- channel wavelength conversion.

The performance improvement imparted by routing and spectrum assignment on flexible grid optical networks is a subject of current extensive investigation. Proposed is an efficient spectrum‐assignment algorithm based on reducing the loss of capacity of future bandwidth‐variable path requests. In all scenarios analysed the proposed algorithm outperformed currently investigated slot assignment algorithms.

Elastic optical network (EON) is fast becoming a key solution for designing optical network with better usage of spectrum resources or other objectives of interest to tenant and/or operators. A primary concern of EONs is to protect the network against failures of its elements, because this kind of event can provoke the loss of substantial amount of traffic. In this paper, we propose a new mixed integer linear programming (MILP) formulation for protecting the network traffic against multiple link failures. The key idea is to use bandwidth squeezing together with grooming capability to provide few extra traffic for protection and guarantee a minimum bandwidth for each source-destination node pair under multiple failure events. The proposed formulation solves the virtual topology design problem jointly with the grooming, routing, modulation and spectrum allocation (RMSA) tasks. Due to the non-deterministic polynomial time (NP-hard) nature of the proposed MILP formulation, a heuristic strategy (referred to as two-step MILP) for large networks is also proposed. The solutions and performance of the proposed MILP formulation and two-step MILP analyzed through case studies in a small network. In addition, the performance of three large networks is assessed for cases scenarios where connections are under different service-level agreement (SLA). In view of proposed formulation and two-step MILP, it is possible to identify the configurations that ensure better usage of spectrum resources with different kinds of protection against single or multiple link failures.