This paper presents the practical development of a hybrid quantum-classical network through multiple links of four- and seven-core industrial jacketed multicore fiber. The network utilizes dense wavelength division multiplexing to propagate the C-band quantum and classical information in the same core, making full use of the unidirectional nature of quantum key distribution. Total network transmission of 1.16 Tbps is achieved with a total network secret key rate of approximately 7.4 kbps through a combination of 1 and 2 km links of multicore fiber. The deployment configurations presented are independent of the classical modulation format, and the maximal transmission rate for an operational hybrid network is found to be dependent only on classical optical power occupying the quantum channel wavelength. A model was developed to estimate the impact classical optical channels will have on coexisting quantum channels, which may allow engineers to quickly validate hybrid network designs.
{"title":"Demonstration of a three-node wavelength division multiplexed hybrid quantum-classical network through multicore fiber","authors":"Joshua Dugre;Samuel Fritsch;R. Krishna Mohan","doi":"10.1364/JOCN.537196","DOIUrl":"https://doi.org/10.1364/JOCN.537196","url":null,"abstract":"This paper presents the practical development of a hybrid quantum-classical network through multiple links of four- and seven-core industrial jacketed multicore fiber. The network utilizes dense wavelength division multiplexing to propagate the C-band quantum and classical information in the same core, making full use of the unidirectional nature of quantum key distribution. Total network transmission of 1.16 Tbps is achieved with a total network secret key rate of approximately 7.4 kbps through a combination of 1 and 2 km links of multicore fiber. The deployment configurations presented are independent of the classical modulation format, and the maximal transmission rate for an operational hybrid network is found to be dependent only on classical optical power occupying the quantum channel wavelength. A model was developed to estimate the impact classical optical channels will have on coexisting quantum channels, which may allow engineers to quickly validate hybrid network designs.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 2","pages":"71-80"},"PeriodicalIF":4.0,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10843975","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142993278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Piero Castoldi;Rana Abu Bakar;Andrea Sgambelluri;Juan Jose Vegas Olmos;Francesco Paolucci;Filippo Cugini
Data processing units (DPUs) with embedded graphics processing units (GPUs) have the potential to revolutionize optical network functionalities at the edge. These advanced units can significantly enhance the performance and capabilities of optical networks by integrating powerful processing capabilities directly at the network edge, where data is generated and consumed. We explore the use cases for DPUs in optical data monitoring with local artificial intelligence (AI) processing and embedded security. This paradigm shift aims to enable more efficient data handling, reduced latency, and improved overall network performance by leveraging local AI processing capabilities embedded within DPUs. In this paper, we show how DPUs can analyze vast amounts of optical data in real-time, implementing advanced data analysis algorithms and security protocols directly on the DPUs to provide robust monitoring and protection for the optical networks. Results indicate that DPUs with embedded GPUs can significantly improve the detection and response times to network anomalies, performance issues, and security threats.
{"title":"Programmable packet-optical network security and monitoring using DPUs with embedded GPUs [Invited]","authors":"Piero Castoldi;Rana Abu Bakar;Andrea Sgambelluri;Juan Jose Vegas Olmos;Francesco Paolucci;Filippo Cugini","doi":"10.1364/JOCN.534525","DOIUrl":"https://doi.org/10.1364/JOCN.534525","url":null,"abstract":"Data processing units (DPUs) with embedded graphics processing units (GPUs) have the potential to revolutionize optical network functionalities at the edge. These advanced units can significantly enhance the performance and capabilities of optical networks by integrating powerful processing capabilities directly at the network edge, where data is generated and consumed. We explore the use cases for DPUs in optical data monitoring with local artificial intelligence (AI) processing and embedded security. This paradigm shift aims to enable more efficient data handling, reduced latency, and improved overall network performance by leveraging local AI processing capabilities embedded within DPUs. In this paper, we show how DPUs can analyze vast amounts of optical data in real-time, implementing advanced data analysis algorithms and security protocols directly on the DPUs to provide robust monitoring and protection for the optical networks. Results indicate that DPUs with embedded GPUs can significantly improve the detection and response times to network anomalies, performance issues, and security threats.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 2","pages":"A178-A195"},"PeriodicalIF":4.0,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142993279","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}
Ramon Casellas;Ricardo Martinez;Ricard Vilalta;Raul Munoz
This paper, an extended version of a tutorial presentation given at OFC’24, aims to provide an overview of key aspects in the design and development of a control plane for multiband over spatial division multiplexing optical networks following software defined networking principles. The tutorial will address system design considerations such as the systematic use of data modeling model-driven development; will detail selected, industry-adopted northbound and southbound interfaces for full and partially disaggregated networks; and will introduce advanced considerations such as accounting for physical layer impairments, externalizing path computation and path validation functions or the multilevel control when considering the management of network media channels over dynamically switched spatial channels. We show a prototype of an SDN controller with multigranular nodes combining flexigrid DWDM switching over SDM/core switching, including transport API extensions for the new protocol layer qualifier.
本文是在 OFC'24 上发表的教程演讲的扩展版，旨在概述按照软件定义网络原则设计和开发多频带空间分复用光网络控制平面的关键方面。该教程将讨论系统设计的注意事项，如系统地使用数据建模模型驱动开发；将详细介绍针对完全和部分分解网络选定的、业界采用的北向和南向接口；并将介绍一些高级注意事项，如考虑物理层损伤、路径计算和路径验证功能外部化或在动态交换空间通道上管理网络媒体通道时的多级控制。我们展示了具有多粒度节点的 SDN 控制器原型，该控制器将柔性网格 DWDM 交换与 SDM/核心交换相结合，包括针对新协议层限定符的传输 API 扩展。
{"title":"Overview of SDN control of multiband over SDM optical networks with physical layer impairments [Invited Tutorial]","authors":"Ramon Casellas;Ricardo Martinez;Ricard Vilalta;Raul Munoz","doi":"10.1364/JOCN.536816","DOIUrl":"https://doi.org/10.1364/JOCN.536816","url":null,"abstract":"This paper, an extended version of a tutorial presentation given at OFC’24, aims to provide an overview of key aspects in the design and development of a control plane for multiband over spatial division multiplexing optical networks following software defined networking principles. The tutorial will address system design considerations such as the systematic use of data modeling model-driven development; will detail selected, industry-adopted northbound and southbound interfaces for full and partially disaggregated networks; and will introduce advanced considerations such as accounting for physical layer impairments, externalizing path computation and path validation functions or the multilevel control when considering the management of network media channels over dynamically switched spatial channels. We show a prototype of an SDN controller with multigranular nodes combining flexigrid DWDM switching over SDM/core switching, including transport API extensions for the new protocol layer qualifier.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 2","pages":"A165-A177"},"PeriodicalIF":4.0,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142976072","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}
Giuseppe Rizzelli;Mariacristina Casasco;Valter Ferrero;Annachiara Pagano;Roberto Gaudino
We present in this paper a detailed brainstorming on the future option of merging the metro and the passive optical network (PON) access network segments, enabled by the introduction of end-to-end coherent transmission. We begin by reporting the experimental results presented by our group at OFC2024 (for which this paper is an invited extension). Starting from these preliminary but very promising results, we elaborate on two different possible schematics for metro+PON convergence using edge reconfigurable optical add-drop multiplexers (ROADMs) at the boundary of the two segments, and then we study their physical layer scalability by a mix of experimental characterization and numerical modeling. We show that coherent transceivers enable excellent performance in this scenario, allowing at least 200G per wavelength and even 400G in most cases when traversing all-optically two ROADMs before being routed towards a high splitting ratio PON in the access part of the network. We study several realistic conditions analyzing different bit rates, modulation formats, and network architectures, showing the physical layer conditions that would enable the PON optical distribution network loss to be in the range from 29 to 35 dB, as required by current international standards. The scalability analysis is first based on link budget and optical signal-to-noise ratio (OSNR) fundamental limitations, and it is then extended considering other physical layer issues, such as tight optical filtering in the ROADMs.
{"title":"Analysis and experimental demonstration of possible architectures for future coherent metro+PON converged networks [Invited]","authors":"Giuseppe Rizzelli;Mariacristina Casasco;Valter Ferrero;Annachiara Pagano;Roberto Gaudino","doi":"10.1364/JOCN.538835","DOIUrl":"https://doi.org/10.1364/JOCN.538835","url":null,"abstract":"We present in this paper a detailed brainstorming on the future option of merging the metro and the passive optical network (PON) access network segments, enabled by the introduction of end-to-end coherent transmission. We begin by reporting the experimental results presented by our group at OFC2024 (for which this paper is an invited extension). Starting from these preliminary but very promising results, we elaborate on two different possible schematics for metro+PON convergence using edge reconfigurable optical add-drop multiplexers (ROADMs) at the boundary of the two segments, and then we study their physical layer scalability by a mix of experimental characterization and numerical modeling. We show that coherent transceivers enable excellent performance in this scenario, allowing at least 200G per wavelength and even 400G in most cases when traversing all-optically two ROADMs before being routed towards a high splitting ratio PON in the access part of the network. We study several realistic conditions analyzing different bit rates, modulation formats, and network architectures, showing the physical layer conditions that would enable the PON optical distribution network loss to be in the range from 29 to 35 dB, as required by current international standards. The scalability analysis is first based on link budget and optical signal-to-noise ratio (OSNR) fundamental limitations, and it is then extended considering other physical layer issues, such as tight optical filtering in the ROADMs.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 2","pages":"A142-A154"},"PeriodicalIF":4.0,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142938003","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}
Digital signature (DS) is an essential application of cryptography, used to certify the provenance of a message and its authenticity, guaranteeing the non-repudiation, unforgeability, and transferability of messages. However, the forthcoming advent of quantum computation poses a significant threat to classical signature schemes. A possible solution could be the introduction of novel DS schemes based on the fundamental laws of quantum physics. Recently, several quantum DS (QDS) protocols have been proposed, even relying on the exploitation of off-the-shelf quantum key distribution (QKD) solutions. However, their efficiency and large signature size, uncorrelated to the size of the message to sign, represent the main limitation in their employment in a practical scenario. A trade-off solution could be a quantum-assisted DS (QADS), where the QKD technology is exploited together with classical cryptographic functions to achieve a stronger DS scheme, more resistant even to quantum attacks. We propose a generalized quantum-assisted digital signature (G-QADS) protocol based on a hybrid system, composed by the standard Wegman-Carter Message Authentication Code (WG-MAC) together with symmetric QKD keys, to enhance the security of the DS, allowing messages with arbitrary lengths to be signed while maintaining a suitable DS length. In this work, the G-QADS process is proposed for a three-party configuration (one signer and two verifiers), where the third participant is involved in the procedure just in the case of contention between the other two parties. The G-QADS protocol is then experimentally tested to prove its resilience to forging and non-repudiation attacks, demonstrating its capability in securing the message signature (with a success probability of the attacks ${ lt }10^{- 18}$ ). The performance is experimentally tested exploiting QKD prototypes based on standard BB84 protocol with decoy states and polarization encoding, in a software-defined network (SDN) infrastructure supervised by a single SDN controller, which provides the management of both classical and quantum communication channels. The proposed solution could push the practical exploitation of QKD into a new application domain, leading to a more pervasive integration of quantum technology in realistic scenarios.
{"title":"Generalized quantum-assisted digital signature service in an SDN-controlled quantum-integrated optical network","authors":"Alessio Giorgetti;Nicola Andriolli;Marco Ferrari;Elisabetta Storelli;Gennaro Davide Paduanelli;Antonino Cacicia;Rudi Paolo Paganelli;Alberto Tarable;Emilio Paolini;Giada Sajeva;Marco Brunero;Alessandro Gagliano;Paolo Martelli;Pietro Noviello;Giovanni Schmid;Alberto Gatto","doi":"10.1364/JOCN.534089","DOIUrl":"https://doi.org/10.1364/JOCN.534089","url":null,"abstract":"Digital signature (DS) is an essential application of cryptography, used to certify the provenance of a message and its authenticity, guaranteeing the non-repudiation, unforgeability, and transferability of messages. However, the forthcoming advent of quantum computation poses a significant threat to classical signature schemes. A possible solution could be the introduction of novel DS schemes based on the fundamental laws of quantum physics. Recently, several quantum DS (QDS) protocols have been proposed, even relying on the exploitation of off-the-shelf quantum key distribution (QKD) solutions. However, their efficiency and large signature size, uncorrelated to the size of the message to sign, represent the main limitation in their employment in a practical scenario. A trade-off solution could be a quantum-assisted DS (QADS), where the QKD technology is exploited together with classical cryptographic functions to achieve a stronger DS scheme, more resistant even to quantum attacks. We propose a generalized quantum-assisted digital signature (G-QADS) protocol based on a hybrid system, composed by the standard Wegman-Carter Message Authentication Code (WG-MAC) together with symmetric QKD keys, to enhance the security of the DS, allowing messages with arbitrary lengths to be signed while maintaining a suitable DS length. In this work, the G-QADS process is proposed for a three-party configuration (one signer and two verifiers), where the third participant is involved in the procedure just in the case of contention between the other two parties. The G-QADS protocol is then experimentally tested to prove its resilience to forging and non-repudiation attacks, demonstrating its capability in securing the message signature (with a success probability of the attacks \u0000<tex>${ lt }10^{- 18}$</tex>\u0000). The performance is experimentally tested exploiting QKD prototypes based on standard BB84 protocol with decoy states and polarization encoding, in a software-defined network (SDN) infrastructure supervised by a single SDN controller, which provides the management of both classical and quantum communication channels. The proposed solution could push the practical exploitation of QKD into a new application domain, leading to a more pervasive integration of quantum technology in realistic scenarios.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 2","pages":"A155-A164"},"PeriodicalIF":4.0,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142938004","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}
This paper discusses an optical continuum as a key technique to help telecom operators reduce the total cost of ownership (TCO) of their optical networks. Enabling photonic technologies are reviewed, with a focus on recent advances in reconfigurable optical add drop multiplexers (ROADMs) based on silicon photonics.
{"title":"Will a metro-access optical continuum ever fly? Access network evolution trends and enabling technologies [Invited]","authors":"Fabio Cavaliere;Paola Iovanna;Alberto Bianchi;Roberto Sabella;Alessandro Percelsi","doi":"10.1364/JOCN.533992","DOIUrl":"https://doi.org/10.1364/JOCN.533992","url":null,"abstract":"This paper discusses an optical continuum as a key technique to help telecom operators reduce the total cost of ownership (TCO) of their optical networks. Enabling photonic technologies are reviewed, with a focus on recent advances in reconfigurable optical add drop multiplexers (ROADMs) based on silicon photonics.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 2","pages":"A134-A141"},"PeriodicalIF":4.0,"publicationDate":"2025-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142938002","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}
Oscar Gonzalez de Dios;Pablo Armingol Robles;Liesbeth Roelens;Alejandro Muniz-Da-Costa;Ignacio de Miguel;Ramon J. Duran Barroso;Juan Pedro Fernandez-Palacios
With increasing demand for customized connectivity, transport networks must evolve towards autonomous and customer-driven network management. This paper presents a comprehensive overview of network autonomy and the challenges associated with evolving toward higher levels of autonomy. Moreover, various use cases of artificial intelligence in network automation in IP-over-DWDM transport networks are also analyzed, in particular related to traffic prediction, quality of transmission, anomaly detection, network planning, and proactive failure management. Additionally, the role of generative AI in network operation is explored. Central to our discussion is a proposed control architecture based on open and standard SDN APIs, which incorporates network slicing for multi-layer transport networks and enables real-time access to normalized data, facilitating autonomous network operation.
{"title":"Automation of multi-layer multi-domain transport networks and the role of AI [Invited]","authors":"Oscar Gonzalez de Dios;Pablo Armingol Robles;Liesbeth Roelens;Alejandro Muniz-Da-Costa;Ignacio de Miguel;Ramon J. Duran Barroso;Juan Pedro Fernandez-Palacios","doi":"10.1364/JOCN.537463","DOIUrl":"https://doi.org/10.1364/JOCN.537463","url":null,"abstract":"With increasing demand for customized connectivity, transport networks must evolve towards autonomous and customer-driven network management. This paper presents a comprehensive overview of network autonomy and the challenges associated with evolving toward higher levels of autonomy. Moreover, various use cases of artificial intelligence in network automation in IP-over-DWDM transport networks are also analyzed, in particular related to traffic prediction, quality of transmission, anomaly detection, network planning, and proactive failure management. Additionally, the role of generative AI in network operation is explored. Central to our discussion is a proposed control architecture based on open and standard SDN APIs, which incorporates network slicing for multi-layer transport networks and enables real-time access to normalized data, facilitating autonomous network operation.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 2","pages":"A124-A133"},"PeriodicalIF":4.0,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10823390","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142918122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The ever-increasing demand for improved speeds, expanded bandwidth, and reduced latency in emerging applications has not only driven the recent advanced algorithm breakthroughs but also fostered closer integration of metro and access networks. This work proposes a novel all-optical metro-access integration network (MAIN) enabled by coherent digital subcarrier multiplexing technology. This specially designed architecture can effectively eliminate the latency and jitters caused by the optical–electrical–optical conversion in the conventional scheme and save wavelength resources at the same time. For experimental validation, we successfully demonstrate 400G bidirectional coherent transmission within our proposed architecture, involving three nodes in the metro network and the access network as an example. Also, the related problems during the transmission are extensively discussed with the experimental results. Finally, we reach an aggregation rate of ${4} times {100};{rm Gbps}$ using a DP-16QAM signal. By integrating a SOA into the transmitter of the ONU, a power budget of 32.6 dB with a 29 dB dynamic range is achieved. In addition, the experimental results also show that the proposed all-optical MAIN architecture can be smoothly combined with the TFDM scheme to further enhance the flexibility, which also paves the way for further research on the next-generation coherent metro and access network.
{"title":"All-optical metro-access integration network bidirectional transmission enabled by coherent digital subcarrier multiplexing","authors":"Yongzhu Hu;An Yan;Junhao Zhao;Sizhe Xing;Chao Shen;Ziwei Li;Yingjun Zhou;Jianyang Shi;Zhixue He;Nan Chi;Junwen Zhang","doi":"10.1364/JOCN.541599","DOIUrl":"https://doi.org/10.1364/JOCN.541599","url":null,"abstract":"The ever-increasing demand for improved speeds, expanded bandwidth, and reduced latency in emerging applications has not only driven the recent advanced algorithm breakthroughs but also fostered closer integration of metro and access networks. This work proposes a novel all-optical metro-access integration network (MAIN) enabled by coherent digital subcarrier multiplexing technology. This specially designed architecture can effectively eliminate the latency and jitters caused by the optical–electrical–optical conversion in the conventional scheme and save wavelength resources at the same time. For experimental validation, we successfully demonstrate 400G bidirectional coherent transmission within our proposed architecture, involving three nodes in the metro network and the access network as an example. Also, the related problems during the transmission are extensively discussed with the experimental results. Finally, we reach an aggregation rate of \u0000<tex>${4} times {100};{rm Gbps}$</tex>\u0000 using a DP-16QAM signal. By integrating a SOA into the transmitter of the ONU, a power budget of 32.6 dB with a 29 dB dynamic range is achieved. In addition, the experimental results also show that the proposed all-optical MAIN architecture can be smoothly combined with the TFDM scheme to further enhance the flexibility, which also paves the way for further research on the next-generation coherent metro and access network.","PeriodicalId":50103,"journal":{"name":"Journal of Optical Communications and Networking","volume":"17 1","pages":"58-70"},"PeriodicalIF":4.0,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142880372","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}
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.
{"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}
Gael Simon;Lise Pichard;Fabienne Saliou;Jeremy Potet;Dylan Chevalier;Philippe Chanclou
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.
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