scholarly journals Fragmentation-Aware Traffic Grooming with Lane Changes in Spectrally–Spatially Flexible Optical Networks

Electronics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1502
Author(s):  
Piotr Lechowicz ◽  
Aleksandra Knapińska ◽  
Róża Goścień

Traffic in current networks is constantly increasing due to the growing popularity of various network services. The currently deployed backbone optical networks apply wavelength division multiplexing (WDM) techniques in single-core single-mode fibers (SMFs) to transmit the light. However, the capacity of SMFs is limited due to physical constraints, and new technologies are required in the near future. Spectrally–spatially-flexible optical networks (SS-FONs) are proposed to provide a substantial capacity increase by exploring the spatial dimension. However, before this technology will reach maturity, various aspects need to be addressed. In particular, during traffic grooming, multiple small requests are aggregated into large-capacity optical corridors in an optical layer to increase the spectral efficiency. As the summary traffic volume is dynamically changing, it may be required to set up and tear down optical channels, which results in network fragmentation. As a consequence, in a congested network, part of the requests can be blocked due to the lack of spectrum resources. Thus, the grooming of traffic and the creation of lightpaths should be carefully designed to minimize network fragmentation. In this study, we present several fragmentation metrics and develop a fragmentation-aware traffic grooming algorithm that reduces the bandwidth blocking probability.

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Neeraj Mohan ◽  
Priyanka Kaushal

AbstractThe routing and wavelength assignment (RWA) schemes play an important role in all computer networks. The performance of a computer network and resource utilization largely depend on the RWA. The demand for higher bandwidth is increasing with each passing day, so more efficient RWA schemes need to be devolved to cater the increasing requirements. RWA becomes more challenging for dynamic traffic as the nature and flow of data are not known in advance. In this paper, a dynamic RWA scheme has been proposed for establishing a path in optical networks. The proposed scheme is based upon dynamic conversion sensing algorithm. It can be applied on a number of different network topologies. The proposed scheme is dynamic in nature, which is significantly useful for dynamic traffic grooming. The proposed scheme has been applied on 14 nodes National Science Foundation Network (NFSNet). Simulation results have shown that the blocking probability of this scheme is very low as compared to the existing schemes. So, the proposed dynamic RWA scheme enhances the network efficiency. It is useful for congestion hit networks. The reduced blocking probability in wavelength division multiplexing optical networks leads to better resource utilization and enhanced performance.


2008 ◽  
Vol 2008 ◽  
pp. 1-10
Author(s):  
Miroslav Bahleda ◽  
Karol Blunar

We study the blocking probability and performance of single-fiber and multifiber optical networks with wavelength division multiplexing (WDM). We extend the well-known analytical blocking probability model by Barry and Humblet to the general model, which is proposed for both single-fiber and multifiber network paths with any kind of wavelength conversion (no, limited, or full wavelength conversion) and for uniform and nonuniform link loads. We investigate the effect of the link load, wavelength conversion degree, and the number of wavelengths, fibers, and hops on blocking probability. We also extend the definition of the gain of wavelength conversion by Barry and Humblet to the gain of performance, which is fully general. Thanks to this definition and implementation of our model, we compare different WDM node architectures and present interesting results.


2019 ◽  
Vol 9 (16) ◽  
pp. 3366 ◽  
Author(s):  
Chao Wang ◽  
Yajing Zhang ◽  
Zheng Wu ◽  
Guoxu Zhang ◽  
Yiyang Zhang ◽  
...  

In this paper, the all-solid dual-concentric-core microstructure fiber (MSF) with ultra-broadband dispersion compensation characteristics is designed. The effects of microstructure fiber structure parameters on dispersion, phase-matching wavelength, and kappa value are analyzed by the multi-pole method and mode coupling theory. The average dispersion compensation multiple is 18.45, that is, 1 km long dispersion compensated MSF can compensate for the cumulative dispersion of standard single-mode fiber of 18.45 km in the wavelength range of 1385~1575 nm by optimizing MSF parameters. The change range of residual dispersion is within ±0.72 ps/(nm·km), and the splicing loss with standard single-mode fiber is controlled below 5 dB within the compensation bandwidth of 190 nm. Compared with the air hole-quartz structure dual-concentric-core microstructure fiber, the designed fiber reduces the difficulty of fiber drawing, is easy to splice with standard single-mode fiber, and has wider compensation bandwidth as well as larger compensation multiple than the existing microstructure fiber. This lays a solid foundation for the optimization of dense wavelength division multiplexing networks and the construction of all-optical networks.


2020 ◽  
Vol 41 (4) ◽  
pp. 403-409 ◽  
Author(s):  
Deepak Sharma ◽  
Suresh Kumar

AbstractElastic optical networks (EONs) are new generation optical networks that provide flexible bandwidth and spectrum assignment characteristics to accommodate diverse demand range over traditional dense wavelength division multiplexing (DWDM)-based networks. While overcoming spectrum contiguity and continuity constraints, Routing and Spectrum Assignment (RSA) is a challenging task in EONs. In this article, we have proposed an EON network model. Using existing RSA techniques we have analyzed the performance of the proposed model on the basis of Network Blocking Probability (NBP) and Network Utilization Efficiency (NUE) under variable load conditions. It has been found to be working optimally even at a load of 200 Erlangs.


2019 ◽  
Vol 19 (1) ◽  
pp. 13 ◽  
Author(s):  
Akhmad Hambali ◽  
Brian Pamukti

In this research, we propose hybrid Coarse Wavelength Division Multiplexing/Time Division Multiplexing (CWDM/TDM)-Passive Optical Networks (PON) scheme for optimizing the new technology of Gigabit-PON (GPON) called Next Generation-PON Stage 2 (NG-PON2). The simulation of using this scheme proved that Q-Factor increase and Bit Error Rate (BER) decreased, significantly. We use CWDM scheme for downstream while TDM is used for upstream, and we assimilate both of them with new configuration in bidirectional cable setting. CWDM is used due to low nonlinearity effect like Kerr effects. It has the same working principle based on (Time Wavelength Division Multiplexing-PON) TWDM-PON by differentiating the use of wavelength, it can be easily implemented on existing PON technology, and can be used in single-mode optical fiber (SMF) with greater bandwidth and much cheaper operational costs. From the calculations and simulations, it can be analyzed that the network Hybrid of CWDM / TDM-PON able to work on bit rate of 40/10 Gbps on the number of users 32, 64, and 128, with Q-Factor value is above 6 equal to International Telecommunication Union of Telecommunication (ITU-T) standard. The number of users 32 with two cable lengths of 10 and 20 km have value of Q-Factor 25.960 and 14.815 respectively, while64 users with the same cable length have Q-Factor value of 15.808 and 13.046 respectively. In addition, 128 users with the same cable length have BER value of 17.778 and 12.944 respectively.


2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Himanshi Saini ◽  
Amit Kumar Garg

AbstractDense Wavelength-Division Multiplexing (DWDM) optical networks meet ever-increasing bandwidth demand of internet applications. Network failure results in massive information loss particularly in networks carrying a huge volume of data. Survivability techniques ensure uninterrupted network functioning even in case of failure. Research in the domain of DWDM network survivability has contributed toward the development of protection and restoration techniques to provide resilience in optical networks. In this paper, basic concept of protection and restoration in optical networks has been introduced followed by review and analysis of existing routing and survivability techniques. It is observed that a trade-off among network performance parameters exists for any survivability scheme. A novel scheme, Dynamic Hybrid Technique based on Failure Location and Traffic Priority (DHbLP) adaptable to Quality of Service (QoS) demands, has been proposed. DHbLP is tested for one of the possible failure scenarios in the standard National Science Foundation NETwork (NSFNET) and it is observed that this technique improves network performance in terms of throughput and blocking probability.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Georg Rademacher ◽  
Benjamin J. Puttnam ◽  
Ruben S. Luís ◽  
Tobias A. Eriksson ◽  
Nicolas K. Fontaine ◽  
...  

AbstractData rates in optical fiber networks have increased exponentially over the past decades and core-networks are expected to operate in the peta-bit-per-second regime by 2030. As current single-mode fiber-based transmission systems are reaching their capacity limits, space-division multiplexing has been investigated as a means to increase the per-fiber capacity. Of all space-division multiplexing fibers proposed to date, multi-mode fibers have the highest spatial channel density, as signals traveling in orthogonal fiber modes share the same fiber-core. By combining a high mode-count multi-mode fiber with wideband wavelength-division multiplexing, we report a peta-bit-per-second class transmission demonstration in multi-mode fibers. This was enabled by combining three key technologies: a wideband optical comb-based transmitter to generate highly spectral efficient 64-quadrature-amplitude modulated signals between 1528 nm and 1610 nm wavelength, a broadband mode-multiplexer, based on multi-plane light conversion, and a 15-mode multi-mode fiber with optimized transmission characteristics for wideband operation.


2019 ◽  
Vol 0 (0) ◽  
Author(s):  
I. S. Amiri ◽  
Fatma Mohammed Aref Mahmoud Houssien ◽  
Ahmed Nabih Zaki Rashed ◽  
Abd El-Naser A. Mohammed

AbstractThe 16-channels dense wavelength division multiplexing (DWDM) systems have been optimized by utilizing hybrid configurations of conventional optical fiber amplifiers (EDFA, RAMAN and SOA) and optical photodetectors (PIN, APD(Si) and APD(InGaAs)). The DWDM systems were implemented for 5 Gb/s channel speed using one of these configurations with 100 GHz channel spacing and 25 km amplifying section. The hybrid configurations are the combinations of (PIN + EDFA), (PIN + RAMAN), (PIN + SOA), (APD(Si) + EDFA), (APD(Si) + RAMAN), (APD(Si) + SOA), (APD(InGaAs) + EDFA), (APD(InGaAs) + RAMAN) and (APD(InGaAs) + SOA). Based on BER, Q-factor and eye diagrams, the performance was compared for these configurations under influences of various thermal noise levels of photodetectors over different fiber lengths ranging from 25 km up to 150 km. The results revealed that both APD structures give optimum performance at input power Pin = 5 dBm due to high internal avalanche gain. EDFA outperforms RAMAN and SOA amplifiers. SOA amplifier shows degraded performance because of nonlinearity effects induced. RAMAN amplifier seems to be the best alternative for long reach DWDM systems because it minimizes the effects of fiber nonlinearities. The configuration (APD(Si) + EDFA) is the most efficient and recommended to be used for transmission distance beyond 100 km due to its larger Q-factor.


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