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[Communications in Computer and Information Science] Futuristic Trends in Network and Communication Technologies Volume 958 (First International Conference, FTNCT 2018, Solan, India, February 9–10, 2018, Revised Selected Papers) || Future Perspectives in Elastic Optical Networks
摘要： The new generation Elastic Optical Networks (EONs) based on Orthogonal Frequency Division Multiplexing (OFDM) can accommodate exponentially increasing heterogeneous data traffic efficiently and economically. In EONs, the optimum channel spacing between various subcarriers is very crucial for its efficient performance. The use of Sub-Carrier Multiplexing (SCM) in EONs is visualized as an evolving field. This paper present the evaluation of SCM based EONs for both mathematical and simulative model. The designed SCM-EON network is analytically evaluated for its performance with different modulation techniques (Direct Modulation and External Modulation). The performance of system is also evaluated for amplification using Semiconductor Optical Amplifier (SOA) and Erbium Doped Fiber Amplifier (EDFA). Simulative results show that Optical Phase Modulation (OPM) along with EDFA offers enhanced performance for the proposed model. It has also been observed that OPM is a better technique for SCM and hence it can be deduced that the combination will boost EONs efficiency in handling network resources.
关键词： SCM,Elastic Optical Networks,OFDM,EDFA,OPM,Bandwidth variable-wavelength cross-connects (BV-WXC),Quadrature Amplitude Modulation (QAM),Coherent Optical Orthogonal Frequency Division Multiplexing (CO-OFDM),Mach-Zehnder modulator (MZM)
更新于2025-09-23 15:23:52
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On the efficient optimization of unicast, anycast and multicast flows in survivable elastic optical networks
摘要： The paper investigates efficient allocation of three types of flows (unicast, anycast, multicast) in elastic optical network with dedicated path protection. We model the problem as an integer linear programming and propose efficient solution methods: greedy randomized algorithm (GRA) and column generation (CG)-based approach implemented in two versions, which differ in the method used to find a final problem solution for the selected columns. Then, we evaluate in detail methods efficiency with respect to four reference algorithms. What is more, for CG-based methods we use five different algorithms to find initial sets of columns and, by these means, evaluate how the quality of these methods influences the efficiency of CG-based approaches. The simulation results show that the proposed GRA significantly outperforms reference greedy methods and finds very good solutions (the average gap to optimal result was not higher than 13.4%). The CG-based methods allow to further improve results and obtain solutions very close to optimal ones (for the best CG-based version, the highest average gap to optimal result was 2.1%). Moreover, the results show that the traffic pattern influences the algorithms performance. The methods perform the best for scenarios with high amount of multicast volume while high anycast volume brings the most difficult problem instances. Eventually, the study reveals that the efficiency of CG-based methods depends strongly on the quality of initial columns as well as on the method used to find final solution for the selected columns.
关键词： Network optimization,Multicast traffic,Anycast traffic,Column generation technique,Elastic optical networks,Dedicated path protection
更新于2025-09-23 15:23:52
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Microwave photonics‐based all optical wavelength conversion of Nyquist‐DP‐16QAM for flex‐grid optical networks with 112 Gbps
摘要： We propose and demonstrate an all optical wavelength conversion of Nyquist differential phase 16 quadrature amplitude modulation based on microwave photonics signal processing for flex-grid optical networks. By analyzing the mechanism of the microwave photonics and the components, multi-adjusting the parameters of wavelength tunable laser with smooth and adjustable optical intensity can be obtained. Then, the multi-channel photonic signals with the minimal guard space of 5 GHz can be obtained, which provide more than 20 flex-grids for optical transmission with transparent rate and format. The optical power of converted wavelengths, optical signal-to-noise ratio, error vector magnitude, and bit error rate (BER) are studied under the condition of different flex-grids, the frequencies of which are from 15 GHz to 36 GHz. The channel frequency spacing and amplitude of the converted wavelength can be dynamically adjusted via parameter configuration. Flex-grid spacing strategies and channel selecting strategies are given. The BER performance of all converted channels can fall below the forward error correction threshold of 3.8 × 10?3 by optimizing the optical power of the receiver end. The results show the tradeoff between the BER and the detected optical power of the receiver end. These research findings could provide solutions for spectrum allocation and routing selection when wavelength conversion is needed in optical links.
关键词： coherent communication,microwave photonics,wavelength conversion,flex-grid optical networks
更新于2025-09-23 15:22:29
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[IEEE 2017 International Conference on Optical Network Design and Modeling (ONDM) - Budapest (2017.5.15-2017.5.18)] 2017 International Conference on Optical Network Design and Modeling (ONDM) - Orchestrating data-intensive vNF service chains in inter-DC elastic optical networks
摘要： We investigate the problem of data-intensive vNF service chain (vNF-SC) orchestration in inter-datacenter EONs. After analyzing the N P-hardness of this problem, we solve it in a sequential manner by optimizing both the request serving sequence and the data-intensive vNF-SC orchestration. Specifically, we propose a request sorting algorithm and a data-intensive vNF-SC orchestration algorithm based on dynamic programming to minimize the service completion time. We conduct simulations to evaluate the proposed algorithms, and simulation results verify their effectiveness.
关键词： Network Function Virtualization,vNF Service Chain,Bulk-Data Transfer,Elastic optical networks
更新于2025-09-23 15:22:29
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[IEEE 2018 Asia Communications and Photonics Conference (ACP) - Hangzhou, China (2018.10.26-2018.10.29)] 2018 Asia Communications and Photonics Conference (ACP) - A Marketplace for Real-time Virtual PON Sharing
摘要： We propose a marketplace where multiple network operators coexisting on the same passive optical network (PON) infrastructure can share their excess capacity. We designed a double auction to assure efficient allocation of optical access capacity.
关键词： Network sharing,Passive Optical Networks,Auction,Infrastructure sharing
更新于2025-09-23 15:22:29
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A Performance Comparison of Centralized and Distributed Spectrum Management Techniques in Elastic Optical Networks
摘要： Elastic optical networks (EONs) have emerged to provide higher spectrum efficiency than traditional Dense Wavelength-Division-Multiplexing (DWDM) by utilizing enabling technologies such as flexible spectrum grid, Orthogonal Frequency Division Multiplexing (OFDM), and distance adaptive rate and modulation. The choice of the control-plane is an important consideration when deploying any new technology, especially in optical networks. This paper considers generic distributed and centralized spectrum assignment policies in conjunction with the accompanying connection set-up signaling protocols in EONs. A network simulator for Generalized Multiprotocol Label Switching (GMPLS) was developed with Forward Reservation Protocol and Backward Reservation Protocol signaling methods. These signaling techniques are used with the First Fit (FF) and Random Fit (RF) Routing and Spectrum Allocation (RSA) algorithms. The paper discusses control elements (central and distributed architectures) decisions under busy hour and normal network conditions and presents a comprehensive performance analysis of key performance metrics such as connection success rate, connection establishment time, and capacity requirement.
关键词： distributed control,signaling protocols,GMPLS,routing and spectrum allocation,centralized control,spectrum allocation,Elastic optical networks
更新于2025-09-23 15:22:29
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Modeling the Effect of Wavelength Selective Switch Latency on Optical Flow Switching Performance
摘要： Optical networks are well suited to enable massive data exchanges between datacenters. Elephant data flows can be routed over custom provisioned and dedicated lightpaths (optical flows) while other (mice) flows, which are routed by electronic switches, are unaffected. In some solutions, wavelength-selective switch (WSS) devices are employed in the optical nodes to physically and individually route each lightpath toward its destination. WSS devices take time to be switched and consequently delay the lightpath setup completion time. In this paper, the authors present three approximate Markov chain models to account for three different WSS service policies. These models estimate the expected lightpath setup and teardown time across an optical node that makes use of WSS devices. The first and more conventional policy (model) assumes that each setup and teardown request is handled individually, while the other two policies (models) assume that groups of setup and/or teardown requests are handled together by the WSS. The models’ estimates are compared against the results obtained from a computer-based simulator, where both analytical models and simulator account for experimentally measured WSS response times. The simulator is also used to investigate the end-to-end lightpath setup time across an arbitrary mesh network. Results obtained from the models and simulator show that the group-based service policies outperform the conventional policy at high loads. The group-based policies are especially useful in the presence of lightpaths that are frequently set up and have relatively short holding time (i.e., short duration of elephant-optical flows).
关键词： Circuit switching,Markov chain model,Optical networks,Wavelength selective switch
更新于2025-09-23 15:22:29
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On spectrum assignment in elastic optical tree-networks
摘要： To face the explosion of the Internet traffic, a new generation of optical networks is being developed; the Elastic Optical Networks (EONs). EONs use the optical spectrum efficiently and flexibly, but that gives rise to more difficulty in the resource allocation problems. In this article, we study the problem of Spectrum Assignment (SA) in Elastic Optical Tree-Networks. Given a set of traffic requests with their routing paths (unique in the case of trees) and their spectrum demand, a spectrum assignment consists in allocating to each request an interval of consecutive slots (spectrum units) such that a slot on a given link can be used by at most one request. The objective of the SA problem is to find an assignment minimizing the total number of spectrum slots to be used. We prove that SA is NP-hard in undirected stars of 3 links and in directed stars of 4 links, and show that it can be approximated within a factor of 4 in general stars. Afterwards, we use the equivalence of SA with a graph coloring problem (interval coloring) to find constant-factor approximation algorithms for SA on binary trees with special demand profiles.
关键词： Chordal graphs,Elastic optical networks,Interval coloring,Spectrum assignment
更新于2025-09-23 15:21:21
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Alien Wavelengths Over Optical Transport Networks
摘要： To reduce network infrastructure cost, network operators want to integrate interoperable and open transponders, since these transponders allow application of the latest technologies over legacy networks at a competitive price. This process of using third-party transponders in a given network is commonly called “alien wavelength” support. Yet, moving toward interoperability raises several challenges: incompatible physical parameters, vendor lock-in, and proprietary software. Manual set up of alien wavelengths has been demonstrated, but automating this process is essential to enable alien wavelength operation in the field. This paper sheds light on the prevailing literature on the concept of alien wavelengths, taking into account many challenges that accompany the concept on its various levels. We particularly focus on several approaches proposed in the literature: protocol message translation, controller cooperation, and open line systems, including our own proposals, an OpenROADM-based approach and a RSVP-TE-based approach. We analyze these approaches with respect to several criteria: applicability to legacy equipment, added operational cost, and the offered level of interoperability and openness. According to these characteristics, we note that, even though some non-interoperable approaches might be applicable to legacy equipment and easy to maintain, they remain infeasible with advanced alien scenarios (high level of interoperability). Finally, a combination has to be made between at least two of the given approaches in order to get the optimal solution.
关键词： Optical networks,Network interoperability,Alien wavelength
更新于2025-09-23 15:21:21
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Characterization of a Low-Cost, Monolithically Integrated, Tunable 10G Transmitter for Wavelength Agile PONs
摘要： Dynamically reconfigurable passive optical networks (PONs) using time-division multiplexing and dense wavelength division multiplexing will require low-cost, high-performance customer premises equipment to be economically viable. In particular, substantial cost savings can be achieved through the use of efficient re-growth free, foundry-compatible fabrication techniques. Using this strategy, this paper presents the first detailed characterization of a monolithically integrated transmitter comprised of a discretely tunable slotted Fabry–Pérot ridge waveguide laser, an absorptive modulator and a semiconductor optical amplifier (SOA) produced using a standard off-the-shelf AlInGaAs/InP multiple quantum well epitaxial structure. This first generation device demonstrates a discrete single-mode tuning range of approximately 12 nm between 1551nm and 1563 nm with a side-mode suppression ratio ≥30 dB. Moreover, the integrated modulator section is shown to support transmission at 10 Gb/s using non-return to zero on-off keying with an extinction ratio in excess of 8 dB. Furthermore, using a time-resolved chirp measurement technique to examine dynamic deviations in the set carrier frequency, the modulator section exhibits a chirp contribution of <6 GHz using test patterns with high and low frequency content. In addition, the generation of optical bursts through the application of a gating function to the SOA section was found to shift the unmodulated carrier of a typical lasing mode by ≤8 GHz for gating periods comparable with a typical PON burst durations of 125 μs which are faster than the thermal response time of the transmitter material.
关键词： Optical communications,tunable semiconductor lasers,dense wavelength division multiplexing,passive optical networks,time division multiplexing,monolithic integration
更新于2025-09-23 15:21:01