System reliability of a multistate flow network can be computed in terms all the lower boundary points, called d-minimal paths (d-MPs). Although several algorithms have been proposed literature for d-MP problem, there is still room improvement upon its solution. Here, some new results are presented to improve solution problem. A simple novel algorithm improved solve Diophantine system that appeared Then, an It also explained how used order assess smart grid communication networks. We provide...

Flexible optical network (FON) architectures are considered a very promising solution where spectrum resources allocated within flexible frequency grids. These must handle the more efficiently and support on-demand elastic bandwidth provisioning. However, when multi-bandwidth services coexist without suitable management, blocking of wider calls increases compared to narrower calls. This unfairness effect limits FONs' performance, not fulfilling much promise they hold. In this letter we...

This paper investigates quality of service fairness in grid-less, multi-rate optical networks. By means analytical modeling and simulation, results show that unfairness arises absence suitable control trunk reservation policies may solve the issue.

In this paper we show that the adoption of a simple weighted ordering heuristic strategy to find fixed shortest path routes in topology can improve load-balancing and, consequently, network performance. We compared our routing strategies against k-shortest paths (k-SP) fixed-alternate for three different mesh topologies considering grid networks (FGNs) and elastic optical (EONs). The results performance an system, even with alternate always using path. Results also such easy act mainly...

In this paper, we provide a performance comparison and analysis between hybrid 1-D WDM/OCDMA system 2-D WHTS OCDMA system. the system, OOC is employed as users code sequence of dimension. The simulation results show that presents better than also under standard BER scenario, i.e., = 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-9</sup> , can support at least 75% more simultaneous for analyzed case study. suggests qualified migration...

The Elastic Optical Network (EON) with multirate transmission and supported by bandwidth-variable switching technologies has provided more efficient utilization of spectral resources, leading to improvement the network throughput. However, EON experiences a higher degree fragmentation than conventional fixed-grid networks because spectrum continuity constraint due dynamic nature setup release connections. In this work we propose analyze some metrics, one them applied evaluate only contiguity...

Physical layer security is a crucial step towards fully secure communications systems. The flexibility and ubiquity of digital signal processors in modern wireless optical communication systems open up clear path for the development discrete-signals encryption techniques, which can be implemented relatively cheap. In this paper, we show fundamental role amplitude phase encoding practical implementation linear discrete cryptography (DSC). We focus on spectral these schemes consider...

In this work we study the influence of routing mechanisms when adopting a spectrum partitioning strategy in Flexible Optical Networks. Spectrum is considered because complete sharing available cannot be implemented already deployed optical network. allows coexistence different usage architectures. The influences service blocking probability as well does mechanism. Therefore, should for future studies aiming at fairness, by considering path lengths hybrid network

This paper proposes a methodology to compare scheduling algorithms for congestion resolution in optical burst switching or packet networks, focusing on the issue of wavelength conversion capabilities. The performance such when full is available at nodes are compared with case capabilities over limited range wavelengths. results presented show that not necessarily performing worse than conversion, as long correct terms comparison considered.

We present in this paper the study of electronic buffering an innovative architecture for optical packet/burst switched network (OPSN). This comprises bufferless nodes with packet queuing out layer, deflection routing to perform contention resolution and fully connected mesh topologies under uniform traffic distribution. demonstrate, by means simulation, that studied has a great improvement performance when we introduce such buffers, which are more efficient used optimized topologies.

We propose a novel all-optical encryption technique that shuffles spectral slices of multiple wavelength-division multiplexing (WDM) channels. In particular, we investigate the application this to two WDM 56-Gb/s quadrature phase-shift keying signals. Simulation results reveal encrypted signals could be propagated through transparent optical networks with diameters larger than 500 km and properly decrypted at receiver. The enhances security because it forces eavesdroppers discover shuffled...

We propose a novel digital signal processing (DSP) technique that encrypts multiple baseband signals by dividing them into several spectral slices, which are then shuffled. Afterwards, the shuffled modulate optical carriers and propagated through transparent communication systems. Simulation results reveal reach of is ~ 90% unshuffled ones. also evaluate scenario where transmitted routes to increase security investigate robustness against brute force chosen plaintext attacks.

This work presents an analysis of the performance different routing and wavelength assignment (RWA) spectrum (RSA) algorithms applied to transparent optical networks supporting channels with multiple bandwidths. Two cases are considered. The first one regards elastic grid. second concerns a situation where is divided in blocks that individually assigned A new RSA based on search for shortest path maximum number free frequency slot units (SPMFF) proposed. Investigation encompasses three...

Dynamic allocation and release of lightpaths cause spectral fragmentation degrade the bandwidth occupation in elastic optical networks (EON). Spectral reallocation defragmentation strategies are key issues to minimize this problem should be carefully chosen simplify network management avoid excessive use hardware. In paper, we investigate application three different routing assignment (RSA) algorithms reallocate EON traffic situations where new requested connections may potentially blocked....

The continuous increasing of the Internet traffic has brought serious concerns about capacity exhaustion optical infrastructure in a medium term horizon. Taking into account networks, comprising backbone, strategies to avoid this catastrophic scenario point development new technologies that enable expansion, as well better utilization network resources (spectrum or wavelengths). elastic network, considered realistic perspective for infrastructure, optimizes required spectrum and improve...

We have investigated the performance of various optical packet switched network (OPSN) architectures comprising bufferless nodes and fully connected mesh topologies, under uniform traffic distribution, i.e., all generate same traffic. demonstrate that increasing number in OSPNs does not necessarily increase performance, or even capacity. By establishing an efficiency parameter based on average hops effective capacity, decision tables graphs can be generated utilized planning. Moreover,...

This paper proposes and investigates the performance of a dynamic routing wavelength code assignment (RWCA) algorithm using hybrid technology with optical division multiplexing (WDM/OCDM) for Optical Burst Switching (OBS) network. An OCDM-based multigranularity cross-connect (MG-OXC) is used to enable better granularity in path (wavelength code) switching than wavelength-based path. The results show that Random-Random heuristic has when burst blocking probability as function traffic load...

In this paper we study the behavior of traffic in Metropolitan Access Optical Networks with technologies optical packet/burst switching (OPS/OBS), using computer modeling and simulations. We analyze network performance impact link failure when electronic buffering at ingress (client input) to is implemented. Mesh ring topologies are chosen parameters packet loss fraction average number hops adopted for metrics. The use minimum demonstrated improve access layer, necessary keep low throughput...