Open-Source Software Defined Networking Controllers:State-of-the-Art,Challenges and Solutions for Future Network Providers

Software Defined Networking(SDN)is programmable by separation of forwarding control through the centralization of the controller.The controller plays the role of the‘brain’that dictates the intelligent part of SDN technology.Various versions of SDN controllers exist as a response to the diverse demands and functions expected of them.There are several SDN controllers available in the open market besides a large number of commercial controllers;some are developed tomeet carrier-grade service levels and one of the recent trends in open-source SDN controllers is the Open Network Operating System(ONOS).This paper presents a comparative study between open source SDN controllers,which are known as Network Controller Platform(NOX),Python-based Network Controller(POX),component-based SDN framework(Ryu),Java-based OpenFlow controller(Floodlight),OpenDayLight(ODL)and ONOS.The discussion is further extended into ONOS architecture,as well as,the evolution of ONOS controllers.This article will review use cases based on ONOS controllers in several application deployments.Moreover,the opportunities and challenges of open source SDN controllers will be discussed,exploring carriergrade ONOS for future real-world deployments,ONOS unique features and identifying the suitable choice of SDN controller for service providers.In addition,we attempt to provide answers to several critical questions relating to the implications of the open-source nature of SDN controllers regarding vendor lock-in,interoperability,and standards compliance,Similarly,real-world use cases of organizations using open-source SDN are highlighted and how the open-source community contributes to the development of SDN controllers.Furthermore,challenges faced by open-source projects,and considerations when choosing an open-source SDN controller are underscored.Then the role of Artificial Intelligence(AI)and Machine Learning(ML)in the evolution of open-source SDN controllers in light of recent research is indicated.In addition,the challenges and limitations associated with deploying open-source SDN controllers in production networks,how can they be mitigated,and finally how opensource SDN controllers handle network security and ensure that network configurations and policies are robust and resilient are presented.Potential opportunities and challenges for future Open SDN deployment are outlined to conclude the article.

Threshold-Based Software-Defined Networking(SDN)Solution for Healthcare Systems against Intrusion Attacks

The healthcare sector holds valuable and sensitive data.The amount of this data and the need to handle,exchange,and protect it,has been increasing at a fast pace.Due to their nature,software-defined networks(SDNs)are widely used in healthcare systems,as they ensure effective resource utilization,safety,great network management,and monitoring.In this sector,due to the value of thedata,SDNs faceamajor challengeposed byawide range of attacks,such as distributed denial of service(DDoS)and probe attacks.These attacks reduce network performance,causing the degradation of different key performance indicators(KPIs)or,in the worst cases,a network failure which can threaten human lives.This can be significant,especially with the current expansion of portable healthcare that supports mobile and wireless devices for what is called mobile health,or m-health.In this study,we examine the effectiveness of using SDNs for defense against DDoS,as well as their effects on different network KPIs under various scenarios.We propose a threshold-based DDoS classifier(TBDC)technique to classify DDoS attacks in healthcare SDNs,aiming to block traffic considered a hazard in the form of a DDoS attack.We then evaluate the accuracy and performance of the proposed TBDC approach.Our technique shows outstanding performance,increasing the mean throughput by 190.3%,reducing the mean delay by 95%,and reducing packet loss by 99.7%relative to normal,with DDoS attack traffic.

Examining the Quality Metrics of a Communication Network with Distributed Software-Defined Networking Architecture

Software-Defined Networking(SDN),with segregated data and control planes,provides faster data routing,stability,and enhanced quality metrics,such as throughput(Th),maximum available bandwidth(Bd(max)),data transfer(DTransfer),and reduction in end-to-end delay(D(E-E)).This paper explores the critical work of deploying SDN in large-scale Data Center Networks(DCNs)to enhance its Quality of Service(QoS)parameters,using logically distributed control configurations.There is a noticeable increase in Delay(E-E)when adopting SDN with a unified(single)control structure in big DCNs to handle Hypertext Transfer Protocol(HTTP)requests causing a reduction in network quality parameters(Bd(max),Th,DTransfer,D(E-E),etc.).This article examines the network performance in terms of quality matrices(bandwidth,throughput,data transfer,etc.),by establishing a large-scale SDN-based virtual network in the Mininet environment.The SDN network is simulated in three stages:(1)An SDN network with unitary controller-POX to manage the data traffic flow of the network without the server load management algorithm.(2)An SDN network with only one controller to manage the data traffic flow of the network with a server load management algorithm.(3)Deployment of SDN in proposed control arrangement(logically distributed controlled framework)with multiple controllers managing data traffic flow under the proposed Intelligent Sensing Server Load Management(ISSLM)algorithm.As a result of this approach,the network quality parameters in large-scale networks are enhanced.

Software defined satellite networks:A survey

In recent years,satellite networks have been proposed as an essential part of next-generation mobile communication systems.Software defined networking techniques are introduced in satellite networks to handle the growing challenges induced by time-varying topology,intermittent inter-satellite link and dramatically increased satellite constellation size.This survey covers the latest progress of software defined satellite networks,including key techniques,existing solutions,challenges,opportunities,and simulation tools.To the best of our knowledge,this paper is the most comprehensive survey that covers the latest progress of software defined satellite networks.An open GitHub repository is further created where the latest papers on this topic will be tracked and updated periodically.Compared with these existing surveys,this survey contributes from three aspects:(1)an up-to-date SDN-oriented review for the latest progress of key techniques and solutions in software defined satellite networks;(2)an inspiring summary of existing challenges,new research opportunities and publicly available simulation tools for follow-up studies;(3)an effort of building a public repository to track new results.

Definability and Textural Rough Set Algebras

In this paper,a counterpart of definability is studied in texture spaces.The concept of textural complete field is defined and the relations with textural definable sets are investigated.If a texture is discrete,then textural definability coincides with definability.Using this fact,we obtain some basic results for definability in rough set algebras.Further,we discuss on definability for fuzzy rough sets considering textural fuzzy direlations.

Deployment Strategy for Multiple Controllers Based on the Aviation On-Board Software-Defined Data Link Network

In light of the escalating demand and intricacy of services in contemporary terrestrial,maritime,and aerial combat operations,there is a compelling need for enhanced service quality and efficiency in airborne cluster communication networks.Software-Defined Networking(SDN)proffers a viable solution for the multifaceted task of cooperative communication transmission and management across different operational domains within complex combat contexts,due to its intrinsic ability to flexibly allocate and centrally administer network resources.This study pivots around the optimization of SDN controller deployment within airborne data link clusters.A collaborative multi-controller architecture predicated on airborne data link clusters is thus proposed.Within this architectural framework,the controller deployment issue is reframed as a two-fold problem:subdomain partition-ing and central interaction node selection.We advocate a subdomain segmentation approach grounded in node value ranking(NDVR)and a central interaction node selection methodology predicated on an enhanced Artificial Fish Swarm Algorithm(AFSA).The advanced NDVR-AFSA(Node value ranking-Improved artificial fish swarm algorithm)algorithm makes use of a chaos algorithm for population initialization,boosting population diversity and circumventing premature algorithm convergence.By the integration of adaptive strategies and incorporation of the genetic algorithm’s crossover and mutation operations,the algorithm’s search range adaptability is enhanced,thereby increasing the possibility of obtaining globally optimal solutions,while concurrently augmenting cluster reliability.The simulation results verify the advantages of the NDVR-IAFSA algorithm,achieve a better load balancing effect,improve the reliability of aviation data link cluster,and significantly reduce the average propagation delay and disconnection rate,respectively,by 12.8%and 11.7%.This shows that the optimization scheme has important significance in practical application,and can meet the high requirements of modern sea,land,and air operations to aviation airborne communication networks.

基于SDN的数据中心网络流量负载均衡研究

目前数据中心网络(data center network,DCN)的负载均衡方法存在对大小流的调度缺乏全局实时检测等不足,部分大流会造成拥塞、负载不均衡和带宽碎片等问题.针对上述问题,提出了一种SDN网络流量负载均衡算法—DSA-D.首先,对流量进行分类,为大流计算所有源至目的主机可达路径的最短跳数路径集;然后,根据LLDP和ECHO测量链路时延以求得时延最优路径集;最后,采用概率拟合算法分配路径,实现数据中心网络流量负载均衡.在相同场景下的实验结果表明,与ECMP、Hedera和DIFF算法相比,DSA-D算法具有更好的吞吐量、链路带宽利用率和平均往返时延.

分布式软件定义网络中多域流量工程的路由优化方法

针对分布式软件定义网络(software-defined networking,SDN)中流量管理调度不均衡的流量工程问题,提出一种基于负载均衡的多控制域流量路由优化的解决方案。首先分析控制消息流量的组成、域内通信及域间通信规则;然后基于4种控制消息定义控制链路流量的构成,明确链路承载流量分为控制消息流量和业务流量,建立平衡控制器负载和最小化最大链路利用率的优化模型;最后基于域内通信和域间通信提出两层路由算法。为提高模型求解精度,进一步提出改进离散萤火虫算法求解最优路由。结合ABILENE网络和GEANT网络,分析控制消息流量、控制器负载和链路负载等评价指标。实验结果表明,优化模型能有效实现控制器和链路负载均衡,控制消息流量是流量工程重要组成部分。相比集中控制模式,扁平分布式控制模式的平均控制器负载降低47.3%,最大链路利用率相差不超过15%。

面向软件定义网络的异常流量检测研究综述

针对软件定义网络(SDN)较传统网络更易遭受网络攻击的现实,从技术原理和架构特点出发,对近年来面向软件定义网络的异常流量检测研究进展进行综述,分析了SDN可能遭受网络攻击的组织形式,讨论了当前SDN异常流量检测、异常流量溯源、异常流量缓解相关技术的特点、优势及不足;对当前研究中常用的数据集进行了对比分析,并梳理出一些通用的数据预处理方法;总结并展望了未来SDN环境下异常流量检测方法的研究方向。调研结果可以指导实际应用需求中适配方法的选取,提出待解决的问题和矛盾可为后续研究提供引导。

ADAFT:SDN大规模流表的适应性深度聚合存储架构

为解决软件定义网络(SDN)数据平面中的三态内容可寻址存储器(TCAM)资源紧张问题,提出了一种基于内容表项树的SDN流表深度聚合方法,进而构建一种SDN大规模流表的适应性深度聚合存储架构ADAFT。该架构放宽了聚合表项之间的汉明距离要求,构建内容表项树聚合动作集不同的流表项,显著提高了流表聚合程度。设计了一种TCAM装载率感知的内容表项树动态限高机制,以降低流表查找开销。同时,提出了一种TCAM装载率感知的表项聚合适应性选择策略,以均衡流表聚合程度和查找开销。实验结果表明,ADAFT架构的流表压缩率明显高于现有方法,最高可达65.74%。

某三甲医院药字号肠内营养制剂的使用分析

目的分析西安市某三甲医院药字号肠内营养制剂的使用情况,为临床合理使用药字号肠内营养制剂提供参考。方法从该院信息管理系统(hospital information system,HIS)中提取2019年至2021年药字号肠内营养制剂的用药数据,对全院药字号营养制剂的销售情况及构成比、用药频度(defined daily doses,DDDs)、限定日费用(defined daily cost,DDC)等药物经济学指标以及各科室使用量进行回顾性统计分析。结果该院肠内营养制剂使用量2019年至2020年呈增长趋势,但2021年度有所下降。DDDs排名前3的制剂分别是百普力、能全素和瑞素。DDC排序前3的制剂是瑞先、百普素和百普力。肝胆外科3年间短肽类制剂使用量位居第1,整蛋白制剂使用量前3的科室分别是神经内科、重症医学科和康复科。结论该院肠内营养制剂平均年使用量偏低,肠内营养与肠外营养治疗比例不均衡。整蛋白制剂瑞先价格较高,患者经济负担重,肠内营养制剂应保质保效,同时应降低价格。临床肠内营养治疗率远低于实际营养不良反应发生率,营养科需进一步加强与临床科室的沟通协作,提高住院患者肠内营养治疗比例。

面向GPU的5G新型无线电的高吞吐率LDPC译码器

提出了一种基于图形处理单元(graphic processing unit,GPU)的5G软件无线电准循环低密度奇偶校验(low density parity check,LDPC)码译码器,为了节省片上和片下带宽,采用码字缩短和打孔技术、两级量化和数据打包方案,以提升数据带宽的利用率。实验基于Nvidia RTX 2080Ti GPU平台实现了高码率情况下的最小和近似译码算法的并行译码,通过分析GPU上的最优线程设置,将码率为5/6的(2080,1760)LDPC算法的译码吞吐率提升至1.38 Gbit/s,译码吞吐率性能优于现有其他基于GPU的LDPC译码器。

新型配电网中的软件定义技术理念及特征

配电网是支撑新型电力系统建设的重要环节,分布式能源、互动负荷与新型装备的大量接入推动了系统形态的巨大变革。文中立足于配电网在柔性化、数字化、智能化方面发展基础,提出新型配电网的软件定义技术构想,旨在从系统层面解决海量、分散灵活资源的协调利用问题,支撑整体系统运行服务水平提升。基于上述观点,文中从软件定义技术的发展基础入手,分析了其技术思想起源与在配电网中的应用条件,建立了配电网软件定义技术的三层式架构,分析了软件定义灵活性的来源和表现形态,梳理了配电网软件定义技术面临的挑战性问题,初步探讨了在其构建与应用中可能涉及的关键技术。最后,对配电网软件定义技术的未来发展前景进行了总结与展望。

二元广义反码与最优LCD码

基于二元线性码的定义向量理论,引入广义反码及其定义向量概念,确立广义反码、它的参数与二元最优线性码之间的联系。利用广义反码的性质和参数研究对应二元最优线性码的线性补对偶(LCD)性质,证明11类二元最优线性码不是LCD码。该方法突破现有方法的局限性,为研究高维二元LCD的参数确定与构造问题提供了可借鉴的新理论和新方法。

40例肾移植受者感染新型冠状病毒的治疗药物分析

目的为肾移植受者感染新型冠状病毒制订治疗方案提供参考。方法回顾性分析安徽省某三甲医院肾移植病区2022年12月6日至2023年1月5日入院且已符合出院标准的40例患者的用药情况,统计药品金额、用药剂量,计算用药频度(DDDs)和药物利用指数(DUI),分析其用药特点。结果40例患者的药费共244.29万元,约占总住院费用的63.71%,其中抗菌药物费用共142.09万元,约占总药费的58.16%。DDDs排前10位的药品为糖皮质激素、质子泵抑制剂和抗菌药物,100.00%的患者联用2种及以上抗菌药物,最多共使用6种。服用奈玛特韦利托那韦(Paxlovid)或阿兹夫定的患者39例(97.50%),其中两药联用16例(40.00%)。22例(55.00%)患者发生药品不良反应,以腹泻(42.50%)、头晕(37.50%)、转氨酶升高(32.50%)为主。结论肾移植受者感染新型冠状病毒住院期间用药复杂,联用药物较多,应加强病原学送检及培养,根据病原学检测结果进行抗感染治疗。注意药物的相互作用和药品不良反应,实现个体化用药治疗。

面向ET-DQN的卫星网络任务部署算法研究

卫星边缘计算服务已经成为网络的重要组成部分,特别在地面网络稀疏环境下,可显著的提高用户的服务质量.但卫星网络的资源有限性为边缘计算任务的部署带来了巨大困难.因此,本文针对部署位置和计算资源分配不合理而导致任务处理时延过长、卫星能耗过大的问题,在SDN(Software Defined Network)的卫星-地面联合部署网络架构(SDN-Space-Ground Integrated Network,SSGIN)的系统模型下.提出了ET-DQN(Experience Tournament-DQN)的任务部署算法,该算法通过引入经验竞选机制提高经验池利用率和网络训练的效率,解决了经验池利用率低,而造成的网络过估计、难收敛的问题.仿真结果表明,该方法能够有效降低任务的响应时延以及能耗,很好地改善了传统DQN算法收敛速度慢和样本的利用率低下的问题.

入侵意图分析下的软件定义网络DDoS攻击检测方法

为在数据样本回溯期内解决因本地信息熵值增大而造成的服务攻击问题,维护软件定义网络的运行安全性,提出入侵意图分析下的软件定义网络分布式拒绝服务(DDoS)攻击检测方法。按照软件定义网络场景重构原则,确定因果网转换标准,实现对识别参数的更新处理,完成攻击性行为的入侵意图分析,再定义DDoS数据集,根据攻击行为的时空特性,求解模型参数的取值范围,完成入侵意图分析下软件定义网络DDoS攻击检测方法的设计。实验结果表明,在该算法控制下数据样本回溯期为10 min,低于传统算法,能够较好维护软件定义网络的运行安全性。

一种基于云边端架构的雷达组网协同系统设计方案

在现代战争的复杂电磁环境下,基于雷达组网的预警与防空作战体系是应对隐身作战飞机、巡飞弹、无人机、超高音速导弹等多种新质作战对象所形成的多维度多层次立体突防威胁的必然选择。雷达组网系统的协同体系架构是实现防空系统效能增量的关键。文中提出了一种基于云边端架构的雷达组网协同系统设计方案,介绍了以高精度北斗设备为时间频率同步基准的多站空时频同步方法,设计了一种软件化雷达实现方案和两级管控的资源管控系统,阐述了系统能够支持的协同方式及任务类型,详细说明了以子任务为最小颗粒度的资源管控机制,针对任务级和参数级协同任务,揭示了组网系统实时远程紧密闭环反馈式控制原理。最后对本系统的预案设计过程进行了介绍。

基于改进深度强化学习的SDN智能路由

设计了一种基于图神经网络(GNN)和优先经验回放的改进DQN算法(R_DQN)。该算法采用消息传递网络框架进行图结构节点间的信息传播,能够更好地适应网络拓扑这种图结构信息;同时采用优先经验回放机制去学习更有价值的信息,提高样本学习效率,进行算法优化。实验结果表明:该R_DQN算法在网络拓扑和业务模型方面都具有较强的泛化能力,对于训练期间没有见过的网络场景依然有较好的表现,在最大化通信量性能上有较大提升。

软件定义卫星网络中基于业务调度的混合路由算法

为了解决低轨卫星网络高动态拓扑、大数据传输量、多信令开销的问题,满足全球覆盖和海量移动用户日益增长的需求,在研究不同业务性能指标体系的基础上,构建了高低轨卫星协同的软件定义卫星网络架构及虚拟拓扑模型;设计了综合考虑业务到达率和等待时长的优先级赋值函数,并提出一种基于业务感知与调度的联合星间路由算法,该算法包括针对高QoS需求业务的低复杂度轨道内优先转发路由算法和针对低QoS需求业务的链路加权路由算法.仿真结果表明,所提算法在平均端到端时延、丢包率和吞吐量等方面比传统算法均有显著的改善.