Journal of Optical Communications and Networking最新文献

{"title":"Nonblocking conditions for Clos fabrics with non-uniform switch radixes","authors":"Takeru Inoue;Toru Mano;Kazuya Anazawa;Takeaki Uno","doi":"10.1364/JOCN.540792","DOIUrl":"https://doi.org/10.1364/JOCN.540792","url":null,"abstract":"Datacenter networks (DCNs) evolve over years and so comprise switches from different generations. Thus, each stage/layer of the Clos fabric may consist of switches with varying radixes (i.e., different port counts), leading to non-uniform stages. While optical circuit switches are increasingly deployed in DCNs to enhance transmission capacity and energy efficiency, the nonblocking condition, crucial for determining the performance of circuit-switched networks, has been established only for Clos fabrics with uniform stages. This study extends the nonblocking condition to Clos fabrics with non-uniform stages. To facilitate practicality, we formulate the condition using integer linear programming (ILP). Using our novel, to our knowledge, condition, we quantitatively demonstrate how much the nonblocking property is compromised under two practical scenarios, random link failures and network expansion, which would break network uniformity. In particular, we reveal that network expansion, common in DCN evolution, could significantly undermine the nonblocking property. Additionally, we assess the computational efficiency of our ILP formulation, which can successfully evaluate the nonblocking property of a large Clos fabric accommodating 32K terminals/uplinks in just 19 min.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 1","pages":"28-46"},"PeriodicalIF":4.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142844567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Raman scattering impairments caused by 50G-PON introduction and mitigation techniques","authors":"Gael Simon;Lise Pichard;Fabienne Saliou;Jeremy Potet;Dylan Chevalier;Philippe Chanclou","doi":"10.1364/JOCN.542178","DOIUrl":"https://doi.org/10.1364/JOCN.542178","url":null,"abstract":"We explore the impact of stimulated Raman scattering (SRS) in the context of multiple PON generations sharing the same optical distribution network. The 50G-PON, being the last specified ITU-T PON, imposes the use of high launch power to meet strong optical path loss requirements. We show that the XGS-PON upstream could be the first victim of the introduction of 50G-PON since its wavelength spacing maximizes Raman scattering. We exploit a model to describe both in simulation and experiment the SRS-induced depletion on XGS-PON. Assuming that 50G-PON will be deployed on the current passive infrastructure, we also exploit field data to precisely predict the amount of terminations exceeding the requirements. The results show that up to 1.8 dB can be lost on XGS-PON upstream signals, 1.3 dB on the 50G-PON upstream, and 0.5 dB on the G-PON upstream, over a distance of 20 km of fiber. Up to 3% of terminations may be affected, according to our field data exploitation. Improving the receivers’ sensitivity through either better photodiodes, signal processing, or forward error correction could relax the high launch power constraints, and thus the SRS. Deploying an optical splitter at the central office could also limit the power actually launched into the fiber while meeting high split ratios. Finally, decreasing the 50G-PON downstream wavelength seems a possible option to mitigate the Raman scattering.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 1","pages":"47-57"},"PeriodicalIF":4.0,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142843068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intent-based control and management framework for optical transport networks supporting B5G services empowered by large language models [Invited]","authors":"Anna Tzanakaki;Markos Anastasopoulos;Victoria-Maria Alevizaki","doi":"10.1364/JOCN.534909","DOIUrl":"https://doi.org/10.1364/JOCN.534909","url":null,"abstract":"This study focuses on the development of an intent-based networking (IBN) control and management framework automating operations of beyond 5G (B5G) infrastructures supported by optical transport networks to interconnect radio access and core networks. Currently, these infrastructures operate in accordance with the software defined networking (SDN) and network function virtualization (NFV) paradigm, relying on complex northbound and southbound interfaces to expose their (network) capabilities and apply suitable configuration policies to B5G infrastructure. B5G infrastructures are expected to operate over complex heterogeneous transport network and compute domains, each having its own programming language and interfaces. To address the increased complexity of this approach, the present study relies on generative artificial intelligence (GenAI) and large language models (LLMs) to significantly simplify the interaction between different layers and domains through automated translation of configuration policies from one domain to another. More specifically, the developed GenAI models are used to support automated operations of B5G infrastructures by 1) translating high-level intents provided by network operators expressed in the form of natural language into autogenerated optimization code used by the orchestrator and 2) creating autoconfiguration policies for the optical transport network. The semantic accuracy and complexity of the proposed framework to generate appropriate configuration policies are experimentally tested over an optical transport network interconnecting the radio access and core networks of a B5G infrastructure.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 1","pages":"A112-A123"},"PeriodicalIF":4.0,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142825945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Meta-learning-aided QoT estimator provisioning for a dynamic VNT configuration in optical networks","authors":"Xiaoliang Chen;Zhenlin Ouyang;Hanyu Gao;Qunzhi Lin;Zuqing Zhu","doi":"10.1364/JOCN.534417","DOIUrl":"https://doi.org/10.1364/JOCN.534417","url":null,"abstract":"Machine learning (ML)-based quality-of-transmission (QoT) estimation tools will be desirable for operating virtual network topologies (VNTs) that disclose only abstracted views of connectivity and resource availability to tenants. Conventional ML-based solutions rely on laborious human effort on model selection, parameter tuning, and so forth, which can cause prolonged model building time. This paper exploits the learning-to-learn nature by meta learning to pursue automated provisioning of QoT estimators for a dynamic VNT configuration in optical networks. In particular, we first propose a graph neural network (GNN) design for network-wide QoT estimation. The proposed design learns global VNT representations by disseminating and merging features of virtual nodes (conveying transmitter-side configurations) and links (characterizing physical line systems) according to the routing schemes used. Consequently, the GNN is able to predict the QoT for all the end-to-end connections in a VNT concurrently. A distributed collaborative learning method is also applied for preserving data confidentiality. We train a meta GNN with meta learning to acquire knowledge generalizable across tasks and realize automated QoT estimator provisioning by fine tuning the meta model with a few new samples for each incoming VNT request. Simulation results using data from two realistic topologies show our proposal can generalize QoT estimation for VNTs of arbitrary structures and improves the estimation accuracy by up to 18.7% when compared with the baseline.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 1","pages":"A103-A111"},"PeriodicalIF":4.0,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142821267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Discrete-variable quantum key distribution services hosted in legacy passive optical networks [Invited]","authors":"Alessandro Gagliano;Alberto Gatto;Pierpaolo Boffi;Paolo Martelli;Paola Parolari","doi":"10.1364/JOCN.534366","DOIUrl":"https://doi.org/10.1364/JOCN.534366","url":null,"abstract":"Fiber-based quantum key distribution (QKD) systems are mature and commercialized, but their integration into existing optical networks is crucial for their widespread use, in particular in passive optical networks (PONs) if end-to-end quantum-secured communications are to be addressed. While discrete-variable QKD coexistence with classical channels is well-studied in point-to-point links, its performance in point-to-multipoint topologies like PONs has received less attention. We thus developed a numerical tool to estimate quantum-available bandwidth and maximum link lengths for QKD systems in single-fiber PON architectures in coexistence with GPON, XG-PON, NG-PON2, and HS-PON standards. The QKD channel performance is obtained by setting thresholds on the quantum bit error rate and the secret key rate, ultimately limited by spontaneous Raman scattering noise and high optical distribution network losses. We perform a comparison between the performance obtained assuming the asymptotic infinite-key generation rate or taking into account actual implementations in the finite-key regime. We evidence that proper design rules can be obtained as a function of both classical and quantum system parameters to support end-to-end quantum security services in existing optical networks.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 1","pages":"A96-A102"},"PeriodicalIF":4.0,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142810660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optical switching for data centers and advanced computing systems [Invited]","authors":"Giannis Patronas;Nikos Terzenidis;Prethvi Kashinkunti;Eitan Zahavi;Dimitris Syrivelis;Louis Capps;Zsolt-Alon Wertheimer;Nikos Argyris;Athanasios Fevgas;Craig Thompson;Avraham Ganor;Julie Bernauer;Elad Mentovich;Paraskevas Bakopoulos","doi":"10.1364/JOCN.534317","DOIUrl":"https://doi.org/10.1364/JOCN.534317","url":null,"abstract":"We explore optical switching to extend network programmability to the physical layer and discuss applications of a Layer-1 software-defined network (SDN) in AI/HPC clusters. In this context we identify two applications for optical circuit switches (OCSs): failure resilience and reconfigurable topologies for deep learning workloads. We present experimental results from a DGX-based testbed towards improving failure resilience and a simulation analysis for efficient deep learning training in AI clusters.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 1","pages":"A87-A95"},"PeriodicalIF":4.0,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142810662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Topology Bench: systematic graph-based benchmarking for core optical networks","authors":"Robin Matzner;Akanksha Ahuja;Rasoul Sadeghi;Michael Doherty;Alejandra Beghelli;Seb J. Savory;Polina Bayvel","doi":"10.1364/JOCN.534477","DOIUrl":"https://doi.org/10.1364/JOCN.534477","url":null,"abstract":"Topology Bench is a comprehensive topology dataset designed to accelerate benchmarking studies in optical networks. The dataset, focusing on core optical networks, comprises publicly accessible and ready-to-use topologies, including (a) 105 georeferenced real-world optical networks and (b) 270,900 validated synthetic topologies. Prior research on real-world core optical networks has been characterized by fragmented open data sources and disparate individual studies. Moreover, previous efforts have notably failed to provide synthetic data at a scale comparable to our present study. Topology Bench addresses this limitation, offering a unified resource, and represents a 61.5% increase in spatially referenced real-world optical networks. To benchmark and identify the fundamental nature of optical network topologies through the lens of graph-theoretical analysis, we analyze both real and synthetic networks using structural, spatial, and spectral metrics. Our comparative analysis identifies constraints in real optical network diversity and illustrates how synthetic networks can complement and expand the range of topologies available for use. Currently, topologies are selected based on subjective criteria, such as preference, data availability, or perceived suitability, leading to potential biases and limited representativeness. Our framework enhances the generalizability of optical network research by providing a more objective and systematic approach to topology selection. A statistical and correlation analysis reveals the quantitative range of all of these graph metrics and the relationships between them. Finally, we apply unsupervised machine learning to cluster real-world topologies into distinctive groups based on nine optimal graph metrics using K-means. It employs a two-step optimization process: optimal features are selected by maximizing feature uniqueness through principal component analysis, and the optimal number of clusters is determined by maximizing decision boundary distances via support vector machines. We conclude the analysis by providing guidance on how to use such clusters to select a diverse set of topologies for future studies. Topology Bench, openly available via Dataset 1 (https://zenodo.org/records/13921775) and Code 1 (https://github.com/TopologyBench), promotes accessibility, consistency, and reproducibility.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 1","pages":"7-27"},"PeriodicalIF":4.0,"publicationDate":"2024-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142810661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coherent passive optical network: applications, technologies, and specification development [Invited Tutorial]","authors":"Zhensheng Jia;Haipeng Zhang;Karthik Choutagunta;L. Alberto Campos","doi":"10.1364/JOCN.535200","DOIUrl":"https://doi.org/10.1364/JOCN.535200","url":null,"abstract":"This paper presents a comprehensive overview of the emerging coherent passive optical network (CPON) technology and its role in the evolution of next-generation PON architectures. After reviewing the fundamental principles of traditional time-division multiplexed PON and tracking its development across successive standards, the unique benefits of applying coherent detection to PONs are examined. These include enhanced reach, increased split ratios, and improved overall network scalability. The paper explores various use cases, deployment scenarios, and architectural options for CPONs. Critical enabling technologies driving CPON development are analyzed, including upstream preamble design and burst-mode detection, techniques for transceiver cost reduction and implementation simplification, forward error correction, and out-of-band communication channels. Finally, the major industry standardization efforts currently underway to specify CPON across the physical, media access control, and system architecture layers are reviewed. By cohesively covering CPON’s evolution from core concepts to real-world specifications, this tutorial paper provides a definitive reference on this disruptive access network technology.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 1","pages":"A71-A86"},"PeriodicalIF":4.0,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic control, routing, and resource assignment in multi-granular optical node topologies combining wavelength, waveband, and spatial switching for 6G transport networks [Invited]","authors":"Varsha Lohani;Raul Munoz;Ramon Casellas;Lluis Gifre Renom;Carlos Manso;Ricard Vilalta;Ricardo Martinez","doi":"10.1364/JOCN.534789","DOIUrl":"https://doi.org/10.1364/JOCN.534789","url":null,"abstract":"Effective management of end-to-end 6G network services is crucial, with peak capacity requirements for 6G transport connections expected to exceed 1 Tb/s. As demand for high bandwidth rises, there is a growing necessity for high-capacity optical fiber links, including ultra-wideband (UWB) and multiple fiber links within the network. Scaling up to accommodate these demands, designing wavelength-selective switches (WSSs) for such networks significantly increases the port count. To tackle this issue, we propose various multi-granular optical node (MG-ON) architectures utilizing heterogeneous wavelength, waveband, and spatial switching. We evaluate these architectures’ performance against high-capacity wavelength division multiplexed (WDM) networks through various simulation parameters.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 1","pages":"A59-A70"},"PeriodicalIF":4.0,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142777853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Leveraging PLOAM messaging for environmental temperature mapping in aerial-deployed time-division multiple access PONs","authors":"Borja Vidal;Cristian Salgado-Cazorla","doi":"10.1364/JOCN.530723","DOIUrl":"https://doi.org/10.1364/JOCN.530723","url":null,"abstract":"The use of optical access networks with aerial-deployed fiber for deriving maps of environmental temperature is investigated. Telecom operators have thousands of kilometers of deployed fiber to provide last-mile broadband services, which could be leveraged to extract temperature information with no additional cost since data are already available as part of the physical layer operations, administration, and maintenance (PLOAM) traffic. Here, it is shown how this information can be used to develop maps of environmental temperature as a method to complement present weather observation platforms. Preliminary experimental results with a G.984 passive optical network (PON) in operation show the feasibility of the technique.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 1","pages":"1-6"},"PeriodicalIF":4.0,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142777852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}