The lack of standards in the performance evaluation of new resource allocation algorithms in multicore fiber elastic optical networks (MCF-EONs) compromises the fairness when comparing them with the state of the art. This paper reviews the different transmission parameters, network parameters, performance metrics, and baselines used by the recent proposals to build a framework for future benchmarking of such algorithms according to the nature of the network operation, whether static or dynamic. This framework aims to provide standards regarding evaluation criteria, scenarios, and performance metrics, as well as recommendations concerning technology advances to promote methodology and reproducibility in further related studies.
Space division multiplexing (SDM) systems using few-mode fibers (FMF) are essential for next-generation fiber optic communications. Optical amplifiers with low noise, minimal differential modal gain (DMG), and minimal differential spectral gain (DSG) are essential for these systems. In this work, we present a method to design and optimize a two-stage few-mode erbium-doped fiber amplifier (FM-EDFA) using a joint DMG-DSG minimization approach. This methodology involves the pumping profile design and the gain flattening filter design. Simulation results show the two-stage FM-EDFA achieves DMG and DSG below 2.8 dB and 0.42 dB, respectively, with an optical signal-to-noise ratio above 19 dB across the C-band, enabling a system capacity of 48.6 Tbps. This work reveals the effectiveness of this two-stage FM-EDFA for optical amplification in the context of SDM systems.
CSNDSP (2024)
VLC/RF Network Simulator: An Integrated Approach to Optical and Radio Frequency Connectivity
Lisandra
Bravo Alvarez, Danilo
Bórquez-Paredes, Samuel
Montejo-Sánchez
, and
2 more authors
In 2024 14th International Symposium on Communication Systems, Networks and Digital Signal Processing (CSNDSP) , Jul 2024
Hybrid systems composed of visible light communication (VLC) and radio frequency (RF) networks have gained great popularity in recent years, due to their great adaptability, flexibility and reliability in different scenarios. To ensure the success and efficiency of a hybrid VLC/RF network, it is essential to have a simulator that allows different aspects to be evaluated and configured. Using a simulator, it is possible to simulate different scenarios and analyze the network response to these changes, identifying potential problems and defining improvement strategies. This work presents a discrete event simulator for hybrid VLC/RF networks in an indoor hybrid environment composed of VLC and RF networks. The simulator can be used to plan VLC/RF networks and evaluate resource allocation strategies. The developed simulator was validated using hybrid network resource allocation strategies published in the literature and, additionally, was used to evaluate network operation parameters including number of users per access point, connection time, slot and frame allocation for connection and delay.
ICTON (2024)
N-Try buffer allocation strategy for advanced reservation in dynamic Multiband-EON networks
Mirko
Zitkovich, and Danilo
Bórquez-Paredes
In 2024 24th International Conference on Transparent Optical Networks (ICTON) , Jul 2024
This paper presents a buffer-enabled allocation strategy for Advance Reservation (AR) in dynamic Multiband-EONs, targeting reduced bandwidth blocking probability (BBP) and improved Quality of Service (QoS). Utilizing a Search Depth method, it dynamically allocates buffer resources to optimize service time and network efficiency. Simulations demonstrate that higher Search Depth improves QoS and BBP, especially in networks with shorter distances and higher connectivity. However, increased Search Depth introduces a trade-off with computational complexity.
ICTON (2024)
Dynamic Multicore Elastic Optical Networks: A Comparative Study of Performance using Heuristics and Artificial Intelligence
Juan
Pinto-Ríos, Ariel
Leiva, Bárbara Dumas
Feris
, and
7 more authors
In 2024 24th International Conference on Transparent Optical Networks (ICTON) , Jul 2024
This study evaluates a deep reinforcement learning agent against a state-of-the-art heuristic for resource allocation in dynamic multicore elastic optical networks (dynamic MCF-EON), focusing on various multicore fiber architectures. The distance between cores influences inter-core crosstalk (InC-XT), a key parameter. The simulations considered the Eurocore topology, using three-core triangular fiber configurations and hexagonally arranged seven-core fibers. The results show that DRL agents outperform heuristics by an average of 18% in blocking probability, particularly under specific inter-core distance conditions. This superiority is attributed to the adaptability of DRL agents learned during training. The study suggests that DRL algorithms show promise in addressing resource allocation challenges in MCF-EON networks, even under strict constraints.
SIMULTECH (2024)
DREAM-ON GYM: A Deep Reinforcement Learning Environment for Next-Gen Optical Networks
Nicolás
Jara., Hermann
Pempelfort., Erick
Viera.
, and
3 more authors
In Proceedings of the 14th International Conference on Simulation and Modeling Methodologies, Technologies and Applications - SIMULTECH , May 2024
A novel open-source toolkit for a straightforward implementation of deep reinforcement learning (DRL) techniques to address any resource allocation problem in current and future optical network architectures is presented. The tool follows OpenAI GYMNASIUM guidelines, presenting a versatile framework adaptable to any optical network architecture. Our tool is compatible with the Stable Baseline library, allowing the use of any agent available in the literature or created by the software user. For the training and testing process, we adapted the Flex Net Sim Simulator to be compatible with our toolkit. Using three agents from the Stable Baselines library, we exemplify our framework performance to demonstrate the tool’s overall architecture and assess its functionality. Results demonstrate how easily and consistently our tool can solve optical network resource allocation challenges using just a few lines of code applying Deep Reinforcement Learning techniques and ad-hoc heuristics algori thms.
2023
SCCC (2023)
Input Buffer in Dynamic Elastic Optical Networks
Mirko
Zitkovich, and Danilo
Bórquez-Paredes
In 2023 42nd IEEE International Conference of the Chilean Computer Science Society (SCCC) , Oct 2023
This paper explores the implementation of a buffer allocation strategy within Elastic Optical Networks (EONs) to manage connection requests that cannot be immediately allocated. The proposed strategy was evaluated using NSFNet and EuroCore topologies, employing RSA and RMSA algorithms. The results demonstrated a significant reduction in blocking probability with the application of the buffer, especially in lower traffic loads. Nevertheless, this approach led to quality of service challenges and introduced a head-of-line blocking issue. The paper discusses future research directions focusing on achieving a balanced trade-off and exploring multiband contexts.
SIMULTECH (2023)
Event-Oriented Simulation Module for Dynamic Elastic Optical Networks with Space Division Multiplexing
Mirko
Zitkovich, Gabriel
Saavedra, and Danilo
Bórquez-Paredes
In Proceedings of the 13th International Conference on Simulation and Modeling Methodologies, Technologies and Applications - Volume 1: SIMULTECH , Jul 2023
It is well-known that creating Space Division Multiplexing-Elastic Optical Networks (SDM-EON) allocation algorithms can be challenging, especially without the right tools. This paper presents the development of a module of an event-oriented simulator designed to code C++ allocation algorithms in the context of Space Division Multiplexing-Elastic Optical Networks. The built module was tested and validated using an allocation algorithm previously published in the literature. The results were consistent with those in the original article, indicating that the module developed is effective and reliable. The use of specialized tools, such as the module being shown, can significantly increase the effectiveness and precision of this process and can stimulate additional developments in the telecommunications industry.
ONDM (2023)
Geometric Constellation Shaping in Elastic Optical Networks: Performance Analysis on Resource Allocation
Y.
Christiansen, M.
Zitkovich, D.
Bórquez-Paredes
, and
3 more authors
In 2023 International Conference on Optical Network Design and Modeling (ONDM) , May 2023
The benefits from geometrical constellation shaping (GCS) are explored in a dynamic elastic optical network context. Using simulations, we evaluate the blocking performance of different forward error correction schemes and modulation formats over the NSFTNET and EUROCORE network topologies. Results show that GCS leads to a selection of denser modulation formats when solving the resource allocation problem in the network, which in turn reduces the network blocking performance compared to conventional QAM modulation formats. Traffic load increases between 5 and 13% for a blocking probability of 10 −3 are reported.
ONDM (2023)
Approaches to dynamic provisioning in multiband elastic optical networks
A.
Beghelli, P.
Morales, E.
Viera
, and
4 more authors
In 2023 International Conference on Optical Network Design and Modeling (ONDM) , May 2023
The funa is a prevalent concept in Chile that aims to expose a person’s bad behavior, punish the aggressor publicly, and warn the community about it. Despite its massive use on the social networks of Chilean society, the real dissemination of funas among communities is unknown. In this paper, we extract, generate, analyze, and compare the Twitter social network’s spread of three tweets related to “funas” against three other trending topics, through the analysis of global network characteristics over time (degree distribution, clustering coefficient, hop plot, and betweenness centrality). As observed, funas have a specific behavior, and they disseminate as quickly as a common tweet or more quickly; however, they spread thanks to several network users, generating a cohesive group.
A deep reinforcement learning (DRL) approach is applied, for the first time, to solve the routing, modulation, spectrum, and core allocation (RMSCA) problem in dynamic multicore fiber elastic optical networks (MCF-EONs). To do so, a new environment was designed and implemented to emulate the operation of MCF-EONs - taking into account the modulation format-dependent reach and intercore crosstalk (XT) - and four DRL agents were trained to solve the RMSCA problem. The blocking performance of the trained agents was compared through simulation to 3 baselines RMSCA heuristics. Results obtained for the NSFNet and COST239 network topologies under different traffic loads show that the best-performing agent achieves, on average, up to a four-times decrease in blocking probability with respect to the best-performing baseline heuristic method.
Network virtualization is a key enabling technology for “Infrastructure as a Service” provisioning, increasing the flexibility and cost savings offered to customers. By extending the concept of server virtualization to the network infrastructure, the allocation of different, independent virtual networks over a single physical network is carried out on demand. A fundamental challenge in network virtualization systems is to choose which physical nodes and links to use for hosting virtual networks in the physical infrastructure, known as the “virtual network allocation” problem. All virtual network allocation proposals on elastic optical networks assume a centralized operation, deploying a single node with access to the network state global information and assigning resources accordingly. However, such configuration might exhibit the inherent problems of centralized systems: survivability and scalability. In this paper, we present a distributed protocol for resource discovery, mapping, and allocation of network virtualization systems. The distributed protocol is generic enough as to be used with different substrate networks. However, in this paper, it has been adapted to work over an elastic optical network infrastructure, where further considerations regarding the spectrum continuity and contiguity constraints must also be taken into account. The distributed protocol is based on the concept of alliances: upon the arrival of a virtual network request, agents located in the physical network nodes compete to form the first alliance able to host the virtual network. Because the first alliances to be formed are also the ones composed by nearby nodes, a good network resource usage is achieved. The feasibility of the distributed protocol was studied by evaluating its ability to successfully establish virtual networks within acceptable time and with low bandwidth consumption from the coordination messages.
SUM (2022)
Dynamic resource allocation in different ultrawideband optical network topologies
F.
Calderón, D.
Bórquez-Paredes, N.
Jara
, and
4 more authors
In 2022 IEEE Photonics Society Summer Topicals Meeting Series (SUM) , Jul 2022
We study the blocking performance of dynamic resource allocation strategies in ultrawideband elastic optical networks under different topologies. State-of-the-art heuristics are evaluated on four different network topologies. Results show consistent better performance of heuristics that prioritise allocation based on the connections bitrate.
Multi-band elastic optical networks are a promising alternative to meet the bandwidth demand of the ever-growing Internet traffic. In this letter, we propose a family of band allocation algorithms for multi-band elastic optical networks. Employing simulation, we evaluate the blocking performance of 3 algorithms of such a family and compare their performance with the only heuristic proposed to date. Results show that the three new algorithms outperform the previous proposal, with up to one order of magnitude improvement. We expect these results to help advance the area of dynamic resource allocation in multi-band elastic optical networks.
This paper studies the impact of demand-prioritization on Space-Division Multiplexing Elastic Optical Networks (SDM-EON). For this purpose, we solve the static Routing, Modulation Level, Spatial Mode, and Spectrum Assignment (RMLSSA) problem using 34 different explainable demand-prioritization strategies. Although previous works have applied heuristics or meta-heuristics to perform demand-prioritization, they have not focused on identifying the best prioritization strategies, their inner operation, and the implications behind their good performance by thorough profiling and impact analysis. We focus on a comprehensive analysis identifying the best explainable strategies to sort network demands in SDM-EON, considering the physical-layer impairments found in optical communications. Also, we show that simply using the common shortest path routing might lead to higher resource requirements. Extensive simulation results show that up to 8.33% capacity savings can be achieved on average by balanced routing, up to a 16.69% capacity savings can be achieved using the best performing demand-prioritization strategy compared to the worst-performing ones, the most used demand-prioritization strategy in the literature (serving demands with higher bandwidth requirements first) is not the best-performing one but the one sorting based on the path lengths, and using double-criteria strategies to break ties is key for a good performance. These results are relevant showing that a good combination of routing and demand-prioritization heuristics impact significantly on network performance. Additionally, they increase the understanding about the inner workings of good heuristics, a valuable knowledge when network settings forbid using more computationally complex approaches.
This paper studies the physical layer’s impact on the blocking probability and energy consumption of wide-area dynamic elastic optical networks (EONs). For this purpose, we consider five network configurations, each named with a network configuration identifier (NCI) from 1 to 5, for which the Routing, Modulation Level, and Spectrum Assignment (RMLSA) problem is solved. NCI 1–4 are transparent configurations based on all-EDFA, hybrid Raman/EDFA amplifiers (with different Raman gain ratio ΓR ), all-DFRA, and alternating span configuration (EDFA and DFRA). NCI 5 is a translucent configuration based on all-EDFA and 3R regenerators. We model the physical layer for every network configuration to determine the maximum achievable reach of optical signals. Employing simulation, we calculate the blocking probability and the energy consumption of the different network configurations. In terms of blocking, our results show that NCI 2 and 3 offer the lowest blocking probability, with at least 1 and 3 orders of magnitude of difference with respect to NCI 1 and 5 at high and low traffic loads, respectively. In terms of energy consumption, the best performing alternatives are the ones with the worst blocking (NCI 1), while NCI 3 exhibits the highest energy consumption with NCI 2ΓR=0.75 following closely. This situation highlights a clear trade-off between blocking performance and energy cost that must be considered when designing a dynamic EON. Thus, we identify NCI 2 using ΓR=0.25 as a promising alternative to reduce the blocking probability significantly in wide-area dynamic EONs without a prohibitive increase in energy consumption.
arXiv
Flex Net Sim: A Lightly Manual
Felipe
Falcón, Gonzalo
España, and Danilo
Bórquez-Paredes
A common problem in elastic optical networks is to study the behavior of different resources allocation algorithms, such as signal modulation formats or quality of service, in optical networks in dynamic scenarios where connections are assigned and released following different traffic profiles. To achieve this, one of the busiest tools is simulators. Normally each research group has its own simulator created entirely by them, which works on a particular simulation scenario, generating multiple versions of the same simulator. For this reason, this project aims to create a tool that allows focusing on the creation of algorithms, generating a common platform for simulation. We present a C ++ library that contains the most common modules belonging to an event-oriented simulator for flexible grid optical networks. This library allows researchers to worry about algorithm generation rather than maintaining/modifying a simulator. The final product is a library capable of being included in any program written in C ++, allowing the design of resource allocation algorithms through macros used in the same source file of the user that uses the library.
Wide-area optical networks face significant transmission challenges due to the relentless growth of bandwidth demands experienced nowadays. Network operators must consider the relationship between modulation format and maximum reach for each connection request due to the accumulation of physical layer impairments in optical fiber links, to guarantee a minimum quality of service (QoS) and quality of transmission (QoT) to all connection requests. In this work, we present a BER-adaptive solution to solve the routing, modulation format, and spectrum assignment (RMLSA) problem for wide-area elastic optical networks. Our main goal is to maximize successful connection requests in wide-area networks while choosing modulation formats with the highest efficiency possible. Consequently, our technique uses an adaptive bit-error-rate (BER) threshold to achieve communication with the best QoT in the most efficient manner, using the strictest BER value and the modulation format with the smallest bandwidth possible. Additionally, the proposed algorithm relies on 3R regeneration devices to enable long-distances communications if transparent communication cannot be achieved. We assessed our method through simulations for various network conditions, such as the number of regenerators per node, traffic load per user, and BER threshold values. In a scenario without regenerators, the BER-Adaptive algorithm performs similarly to the most relaxed fixed BER threshold studied in blocking probability. However, it ensures a higher QoT to most of the connection requests. The proposed algorithm thrives with the use of regenerators, showing the best performance among the studied solutions, enabling long-distance communications with a high QoT and low blocking probability.
ICTON (2020)
3R Regeneration in Elastic Optical Networks and its Impact on the Network Quality of Service
D.
Bórquez-Paredes, F.
Calderón, N.
Jara
, and
4 more authors
In 2020 22nd International Conference on Transparent Optical Networks (ICTON) , 2020
Signal re-amplification, re-shaping, and re-timing (3R) opto-electronic regeneration is a crucial function to scale elastic optical networks. These devices are especially important on large-scale optical networks, enabling long-distance communications. In this work, we analyze the impact of these devices on the quality of service in wide-area optical networks in terms of blocking probability. To this end, we performed network simulations to obtain the blocking probability of users on diverse scenarios, modifying the number of regeneration devices per node jointly with several parameters such as link distances, bit-error-rate (BER) threshold, and network capacity. We use a physical layer model considering linear and non-linear impairments to compute the maximum reach of each communication for a given bitrate and modulation format for a variety of BER thresholds. The results show the importance of using 3R regeneration in wide-area elastic optical networks (EON). Notwithstanding, a limit was found where adding regenerators per node does not substantially improve the blocking probability. Therefore, a cost-benefit analysis must be done considering the cost involved in installing more of these devices.
Most spectrum allocation algorithms in elastic optical networks apply a greedy approach: A new connection is allocated as long as there are enough spectrum slots to accommodate it. Recently, a different approach was proposed. Named Deadlock–Avoidance (DA), it only establishes a new connection if the portion of spectrum left after allocating it is zero (full-link utilization) or is big enough to accommodate future requests. Otherwise, the connection request is blocked as a way to avoid fragmentation. The performance of DA has been evaluated in a single-link scenario, where its performance is not affected by the slot continuity constraint. In this paper, we evaluate for the first time the blocking performance and fragmentation level of DA in a fully dynamic network scenario with different bitrates and number of slots for a single link, a 4-node bus and a mesh topology. The performance was evaluated by simulation, and a lower bound was also derived using a continuous Markov chain model. Results are obtained for DA and three greedy algorithms: First Fit, Exact Fit and First–Last Fit. Results show that DA significantly decreases fragmentation, and thus, it exhibits a much lower blocking due to fragmentation than the greedy algorithms. However, this decrease is compensated by a new type of blocking due to the selective acceptance of connections. As a result, the extra computational complexity of DA does not compensate a gain in performance.
2017
OFWC (2017)
Network Virtualization Over Elastic Optical Networks: A Survey of Allocation Algorithms
Danilo
Bórquez-Paredes, Alejandra
Beghelli, and Ariel
Leiva
In Optical Fiber and Wireless Communications , Jun 2017
Network virtualization has emerged as a paradigm for cloud computing services by providing key functionalities such as abstraction of network resources kept hidden to the cloud service user, isolation of different cloud computing applications, flexibility in terms of resources granularity, and on-demand setup/teardown of service. In parallel, flex-grid (also known as elastic) optical networks have become an alternative to deal with the constant traffic growth. These advances have triggered research on network virtualization over flex-grid optical networks. Effort has been focused on the design of flexible and virtualized devices, on the definition of network architectures and on virtual network allocation algorithms. In this chapter, a survey on the virtual network allocation algorithms over flexible-grid networks is presented. Proposals are classified according to a taxonomy made of three main categories: performance metrics, operation conditions and the type of service offered to users. Based on such classification, this work also identifies open research areas as multi-objective optimization approaches, distributed architec-tures, meta-heuristics, reconfiguration and protection mechanisms for virtual networks over elastic optical networks.
2016
CSC (2016)
Behavior evaluation of dynamic flexible wavelength allocation algorithms by Markovian and simulation-based analysis
Danilo
Bórquez-Paredes, Alejandra
Beghelli, Ariel
Leiva
, and
1 more author
\textcopyright OSA 2016. Network virtualization and elastic networks have emerged as a paradigm for cloud computing and a solution to the ever increasing traffic, respectively. We review virtual allocation algorithms over elastic networks and identify open research issues.
2015
ICTON (2015)
Deadlock-Avoiding vs. greedy spectrum allocation algorithms in dynamic flexible optical networks
Danilo
Borquez, Alejandra
Beghelli, and Ariel
Leiva
In 2015 17th International Conference on Transparent Optical Networks (ICTON) , Jul 2015
Greedy spectrum allocation algorithms assign the required number of slots to a connection request as long as there are enough contiguous slots available for it. Instead, a deadlock-avoidance algorithm only assigns slots if future connections can be fit in the spectrum void left after assigning the current connection. That is, a deadlock-avoidance algorithm avoids leaving available slots that cannot be used by a future connection. The mean time required to exhaust the spectrum of a deadlock-avoidance approach has been studied in the context of a single flexible-grid link under incremental traffic. However, such algorithm has not been studied under dynamic traffic, where the blocking ratio is relevant, neither considering routes longer than 1 hop. In this paper we evaluate the blocking performance of greedy and deadlock-avoidance algorithms under dynamic traffic, in routes from 1-hop to 3-hops. Simulation results show that - with respect to a greedy approach - there is no benefit from deadlock-avoidance algorithms in 1-hop routes. However, the deadlock-avoidance strategy achieves up 2 orders of magnitude lower blocking than the greedy algorithm when longer routes are considered. This result highlights the importance of using algorithms that prevent spectrum fragmentation for efficient resource utilization in dynamic flexible grid networks.
2014
SENACITEL (2014)
Revisión de algoritmos de asignación de redes virtuales sobre redes ópticas de grilla flexible
Danilo
Bórquez-Paredes, Alejandra
Beghelli, and Ariel
Leiva
In XV Congreso Internacional de Telecomunicaciones , Nov 2014