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.

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.

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.

Service Function Chain Migration in LEO Satellite Networks

With the advancements of software defined network(SDN)and network function virtualization(NFV),service function chain(SFC)placement becomes a crucial enabler for flexible resource scheduling in low earth orbit(LEO)satellite networks.While due to the scarcity of bandwidth resources and dynamic topology of LEO satellites,the static SFC placement schemes may cause performance degradation,resource waste and even service failure.In this paper,we consider migration and establish an online migration model,especially considering the dynamic topology.Given the scarcity of bandwidth resources,the model aims to maximize the total number of accepted SFCs while incurring as little bandwidth cost of SFC transmission and migration as possible.Due to its NP-hardness,we propose a heuristic minimized dynamic SFC migration(MDSM)algorithm that only triggers the migration procedure when new SFCs are rejected.Simulation results demonstrate that MDSM achieves a performance close to the upper bound with lower complexity.

Mitigating while Accessing:A Lightweight Defense Framework Against Link Flooding Attacks in SDN

Link flooding attack(LFA)is a type of covert distributed denial of service(DDoS)attack.The attack mechanism of LFAs is to flood critical links within the network to cut off the target area from the Internet.Recently,the proliferation of Internet of Things(IoT)has increased the quantity of vulnerable devices connected to the network and has intensified the threat of LFAs.In LFAs,attackers typically utilize low-speed flows that do not reach the victims,making the attack difficult to detect.Traditional LFA defense methods mainly reroute the attack traffic around the congested link,which encounters high complexity and high computational overhead due to the aggregation of massive attack traffic.To address these challenges,we present an LFA defense framework which can mitigate the attack flows at the border switches when they are small in scale.This framework is lightweight and can be deployed at border switches of the network in a distributed manner,which ensures the scalability of our defense system.The performance of our framework is assessed in an experimental environment.The simulation results indicate that our method is effective in detecting and mitigating LFAs with low time complexity.

Security Monitoring and Management for the Network Services in the Orchestration of SDN-NFV Environment Using Machine Learning Techniques

Software Defined Network(SDN)and Network Function Virtualization(NFV)technology promote several benefits to network operators,including reduced maintenance costs,increased network operational performance,simplified network lifecycle,and policies management.Network vulnerabilities try to modify services provided by Network Function Virtualization MANagement and Orchestration(NFV MANO),and malicious attacks in different scenarios disrupt the NFV Orchestrator(NFVO)and Virtualized Infrastructure Manager(VIM)lifecycle management related to network services or individual Virtualized Network Function(VNF).This paper proposes an anomaly detection mechanism that monitors threats in NFV MANO and manages promptly and adaptively to implement and handle security functions in order to enhance the quality of experience for end users.An anomaly detector investigates these identified risks and provides secure network services.It enables virtual network security functions and identifies anomalies in Kubernetes(a cloud-based platform).For training and testing purpose of the proposed approach,an intrusion-containing dataset is used that hold multiple malicious activities like a Smurf,Neptune,Teardrop,Pod,Land,IPsweep,etc.,categorized as Probing(Prob),Denial of Service(DoS),User to Root(U2R),and Remote to User(R2L)attacks.An anomaly detector is anticipated with the capabilities of a Machine Learning(ML)technique,making use of supervised learning techniques like Logistic Regression(LR),Support Vector Machine(SVM),Random Forest(RF),Naïve Bayes(NB),and Extreme Gradient Boosting(XGBoost).The proposed framework has been evaluated by deploying the identified ML algorithm on a Jupyter notebook in Kubeflow to simulate Kubernetes for validation purposes.RF classifier has shown better outcomes(99.90%accuracy)than other classifiers in detecting anomalies/intrusions in the containerized environment.

Review of Load Balancing Mechanisms in SDN-Based Data Centers

With the continuous expansion of the data center network scale, changing network requirements, and increasing pressure on network bandwidth, the traditional network architecture can no longer meet people’s needs. The development of software defined networks has brought new opportunities and challenges to future networks. The data and control separation characteristics of SDN improve the performance of the entire network. Researchers have integrated SDN architecture into data centers to improve network resource utilization and performance. This paper first introduces the basic concepts of SDN and data center networks. Then it discusses SDN-based load balancing mechanisms for data centers from different perspectives. Finally, it summarizes and looks forward to the study on SDN-based load balancing mechanisms and its development trend.

Multipath Selection Algorithm Based on Dynamic Flow Prediction

Traditional traffic management techniques appear to be incompetent in complex data center networks, so proposes a load balancing strategy based on Long Short-Term Memory (LSTM) and quantum annealing by Software Defined Network (SDN) to dynamically predict the traffic and comprehensively consider the current and predicted load of the network in order to select the optimal forwarding path and balance the network load. Experiments have demonstrated that the algorithm achieves significant improvement in both system throughput and average packet loss rate for the purpose of improving network quality of service.

一种新型的LTE-A网络切换认证协议

针对典型蜂窝网络LTE-A网络的切换认证问题,本文通过引入SDN(Software Defined Network,软件定义网络),提出了软件定义LTE-A异构网络架构,在中心控制器中共享UE(User Equipment,用户设备)的安全上下文信息,以实现简化切换认证过程,提高认证效率的目标.中心控制器的加入,使蜂窝与核心网通信时需要增加一次信令开销,而LTE-A网络的标准切换认证方法过于复杂,应用在软件定义LTE-A异构网络中,会产生较多的信令开销.基于代理签名的切换认证方法,使UE在验证身份时不用经过核心网,减少了信令开销.在安全性相同的情况下,基于椭圆曲线的加密体系比基于RSA的加密体系计算量更小,有利于减少中心控制器的计算压力.本文采用椭圆曲线代理签名方法,提出了一种新型的切换认证协议,并运用着色Petri网进行建模和仿真分析.仿真结果表明,该协议是有效的,且安全性更高.

求时滞Volterra积分系统最优控制问题近似解的一个迭代算法

对一类典型的复杂系统—含多个非线性时滞的Volterra积分系统,给出其控制作用受限(硬约束)最优控制问题近似解的一个迭代算法,证明了该算法是well-defined的,并在一定的条件下证得了算法的收敛性.

基于云网络的SDN运维节能系统

随着云网络的快速发展,其所提供的云计算和云存储服务,打破了传统物理存储和计算资源的局限制,为人们提供了更加灵活和可扩展性的云应用。本文基于云网络、采用数控分离及可编程的SDN技术综合设计了基于云网络的SDN绿色运维系统。本系统使用RYU控制器,实现了拓扑自动发现、流量监控、网络性能评估、主动节能等模块。同时,本文所设计的系统引入代数连通度作为衡量拓扑连通性指标评估网络稳定性,在保证网络性能稳定的前提实现了基于云网络的SDN运维管理和绿色节能运行系统。

可编程的网络——软件定义网络(续)

本文描述了软件定义网络(SDN)的需求、概念及关键技术,重点分析了SDN的网络结构、OpenFlow模型和OpenFlow交换机。最后,讨论了SDN的应用。

非线性光学晶体K_(3.0)Li_(2.0)Nb_(5.0)O_(15.0)的生长

Potassium lithium niobate single crystal with a dimension of 20mm×15mm×30mm was grown by EFG technique in our laboratory.Compared with Czochralski method for the growth of KLN crystals,EFG technique possesses the following merits.Crack of crystals can be weakened during the lowering of temperature and the crystals free of crack can be obtained.The crystals have no rotation,the growth striation caused by the rotation of the crystals can be eliminated.With action of capillary from a die hole,the convective effect of melt at solid liquid interface can be reduced,therefore the homogeneity of crystals is better than that of crystals obtained by Czochralski method.The growth striation parallels each other and is perpendicular to the growth direction,so the good blue SHG can be obtained when ground wave goes through the KLN crystals.Since capillary force does not fully counteract the convective effect,the inhomogeneity of crystals can’t completely be eliminated.The low SHG conversion efficiency of KLN crystals is mainly caused by inhomogeneneity of crystals.For the growth of incongruent melting crystals,the growth rate is limited by the rejection of impurity,this also makes homogeneity of composition become bad.In the growth of KLN crystals by EFG technique,the fluctuation of the temperature at solid liquid interface should be enough small,and the film thickness of melt should be proper.Too thick film of melt makes the process of crystal growth unstable;too thin film of melt can lead to the constitutional supercooling.

可编程的网络——软件定义网络

本文描述了软件定义网络(SDN)的需求、概念及关键技术,重点分析了SDN的网络结构、OpenFlow模型和OpenFlow交换机。最后,讨论了SDN的应用。

机械产品6σ设计IDDOV中的Define方案实现研究

将产品全寿命周期六西格玛解决方案(Production Life Cycle Six Sigma Solution,LCSS)的六西格玛设计(Design For Six Sigma,DFSS)理论用于机械产品设计研究,在简要介绍IDDOV(Identify,Define,Develop,Optimize,Verify)流程的基础上,分析了顾客需求转换的系统规范,建立了机械产品Define阶段设计的技术体系和数学模型,总结了Define方案实现步骤和评估算法,为机械产品多样化、低成本、高质量和高稳健性设计提供了一种新的解决途径。

Degradation of Soils in the Lowland of Kur-Araz

The research works were carried out for determination of the washout, types, sorts and level of the development reasons of degradation with the purpose of preparation of the measures of fight against degradation in the soils in 2005-2009 in the lowland of Kur-Araz. The investigations were fulfilled by using of geographical and stasionar methods. It is revealed that 333.6 thous, ha of the soils of the lowland of Kur-Araz have been exposed to erosion. 97.4 thousand ha of them have been exposed to rainstorm erosion, 127.1 thous, have been exposed to irrigative and 122.1 thous, ha to wind erosion. The most dangerous of them are considered irrigative erosion. Under the influence of erosion process in deposited over the length of furrow, deposits the changes happened in maintenance of humus and nutritions elements. In dependence on slope and water expenditure on 1 ha 2.23-14.86 t of soil are leached. As a result of out wash from 1 ha of soil 55.88-304.59 kg of humus, 4.06-20.80 kg of nitrogen, 4.57-26.55 of phosphorus and 57.40-372.99 of potassium are lost. The soil is exposed to degradation and as a result a process of desertification begins. On the basis of the quantitative an intensity of soil outwash the possible losses of dry matter including humus and main elements of nutrition of plants as a result of erosion, their deposit with the water way, are calculated, too.

The Defining Schemes of Semantic Prosody

Sinclair is regarded as the father of semantic prosody study,however,the term "semantic prosody" was proposed by another famous linguist——Louw in 1993.From then on,several linguists proposed the definitions for this term and thus the features of semantic prosody become progressively clear.

超立方体网络的EE指数(英文)

一个新的图谱的特征不变量:网络的EE指数被定义为EE=EE(G)=∑i n eλi,λ1,λ2,…,λn为网络的特征多项式对应的特征值.给出了超立方体网络的的EE指数的计算公式.

The Comparative Discussion of State Owned Enterprise in Competition Law

Reflect on the benefits and costs of the current approaches in the European Union and the People’s Republic of China.To the conclusion that State Owned Enterprises(SOE)’s and more generally state conduct should be fully covered by competition law.

基于混合式教学的高职英语“课程思政”的实践研究——以“A Defining Moment”为例

"课程思政"是依托于课程进行思政教育的教学活动,高职英语教师将"立德树人"渗透到英语教学中,旨在提高学生的人文素养,使学生树立正确的价值观。混合式教学是线上学习和课堂学习的有机结合。将混合式教学和"课程思政"相结合进行探索,可作为"课程思政"实现的一种尝试。文章以《新视野英语教程3》第四单元TextA"A Defining Moment"一文教学为例,将其中的德育因素作为思政教育的切入点,采用混合式教学的方式,实证研究课程思政和高职英语教学的有机融合。