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In order to deal with the recent rapid increase in Internet traffic, a transmission technology is required to enable the efficient use of the optical fiber spectrum while offering flexibility in network bandwidth. To meet these challenges, the emergence of Elastic Optical Networks (EON) has brought new conceptions in the operation of optical networks, improving flexibility and efficiency for the next generation core networks. In EON, traffic demands are typically supported by allocating bandwidth-variable optical channels with heterogeneous modulation formats in a spectral-efficient manner. Elastic optical path networks require the routing, modulation level, and spectrum allocation (RMLSA) to efficiently allocate optical spectrum resources to optical paths. To address the RMLSA problem, Modulation Scheme approaches have recently been proposed to allow the use of any routing and spectrum assignment (RSA) algorithm to solve the RMLSA problem. In this paper, we propose a new Modulation Scheme that enables the routing of traffic through dynamic multi-modulation allocation in multiple hops to achieve blocking performance improvement. Numerical results demonstrate that the proposed adaptive modulation scheme achieves a reduction in bandwidth blocking of up to two orders of magnitude in an underloaded network scenario, and 86% with higher loads, playing an important role in spectrum savings compared with the literature schemes., Comment: 10 pages, 16 figures

Software Defined Networks (SDN) emerged as a new paradigm for network management, defining an architecture the physically decouples the control and data planes. An SDN architecture based on a central controller does not scale and neither is fault-tolerant since it presents a single point of failure. Distributed SDN controllers based on an eventually consistent model for the network state also bring serious drawbacks: a complex programming model for network applications; and it can lead to network anomalies. Consequently, solutions considering a consistent model for the network state are emerging. In these approaches, the distributed controllers use a consistent and fault-tolerant data store that keeps relevant network and applications state. Unfortunately, these approaches do not consider security requirements for the SDN. This work aims to design, implement and evaluate a secure and consistent model for the control plane based on DepSpace, a secure tuple space implementation used to coordinate distributed processes. Experimental results show the practical feasibility of the proposed architecture.

Elastic optical networks enter as a promising technology for the future of high-capacity networks. Its features provide flexibility and superior scalability in spectrum allocation following the growing demands of Internet traffic. In this letter, we propose a novel approach to address the routing, modulation level, and spectrum allocation (RMLSA) problem through the use of a distance-adaptive modulation scheme that enables the routing of traffic through multiple hops in virtual topology, enabling smoothing out the spectrum continuity and transmission distance constraints. The results showed that the use of the proposed scheme provide a gain of up to 82% in the bandwidth blocking rate using 7% less spectral resources in the network compared with the literature. This proposal opens a new avenue for future research, allowing new solutions for RMLSA problem.

The technology used for data transmission in optical networks is going through significant changes in response to the rapid growth of Internet traffic and emerging high performance applications, boosting research on how to satisfy the increasing demands with the available resources. In this scenario, the elastic optical networks paradigm enables improved provisioning through flexibility and scalability in spectrum assignment. This work proposes data and optical grooming and the use of spectral modulation control as a solution to the Routing, Modulation Level, and Spectrum Allocation problem in a dynamic traffic context. The proposed algorithm obtains the greatest spectrum aggregation possible using higher modulation levels through multiple hops in the virtual topology. Experiments show that this approach results in reduced blocking without impacting the use of the network's resources.