基于OpenFlow的SDN可靠性综述

软定义网络(SDN)是一种新型的网络架构,其将控制平面和数据转发平面分离,并为网络管理提供了可编程的接口,简化了网络管理。随着基于OpenFlow的SDN技术在现实中的广泛应用,其所存在的问题也凸显出来,可靠性就是其中的一个重要方面。文中针对基于OpenFlow的SDN在可靠性方面存在的问题,分析总结了导致OpenFlow网络失效的因素,将网络失效划分为控制器、链路和节点失效,并归纳出相应的解决方案,探讨了未来基于OpenFlow的SDN在可靠性方面的研究方向与趋势。     

基于OpenFlow的软件定义网络路由技术研究

文中主要探索了基于OpenFlow的软件定义网络（SDN）路由技术,旨在优化和提高网络管理效率。通过深入解读SDN的核心构架、OpenFlow协议的关键组成,并将其与传统路由进行对比,发现SDN提供了一个更加灵活和集中的网络管理机制。在路由决策、性能优化和故障恢复上,基于OpenFlow的SDN明显优于传统方法。由此可见,基于OpenFlow的软件定义网络路由技术不仅可以大大提高网络的运行效率,还能简化网络管理流程,为未来的网络技术发展指明方向。     

基于OpenFlow的SDN技术研究

作为一种新网络架构,SDN实现网络控制平面和数据平面分离,为未来互联网的发展提供一种新解决思路。文中简述OpenFlow与SDN技术的起源与发展,深入阐述SDN/OpenFlow技术的原理和技术标准,论述两大SDN标准制定组织ONF和OpenDayLight的发展现状,并给出SDN市场发展情况。     

迎接SDN/OpenFlow网络测试的挑战

新出现的网络部署场景,例如超大规模数据中心内的虚拟化和云环境,都会使现有的网络技术和架构不堪重负。ONF执行总裁DanPitt描述了传统联网技术面临的3项关键挑战,即成本、敏捷性和设计。事实证明,联网的新方法,即所谓的软件定义联网(SDN)和相关的协议OpenFlow,能够应对这些挑战,并且解决更多的问题。然而,尽管SDN和OpenFlow具备巨大的潜力,但它们仍然会对包括网络测试在内的网络生态体系中的许多方面造成干扰。思博伦通信的《迎接SDN/OpenFlow网络测试的挑战》一文首先对SDN和OpenFlow进行了介绍,然后对其所带来的优势进行了阐述,最后对如何迎接SDN和OpenFlow网络测试的挑战给出了解决方案。     

基于Mininet的网络负载均衡仿真研究

软件定义网络(Software Defined Network, SDN)是一种新型的网络体系架构,其原理是采用OpenFlow对网络结构进行自定义的扩展与管理。为进一步研究SDN架构的特性并实现网络负载均衡,文章基于Mininet仿真工具对SDN的网络负载均衡进行深入研究,分析了OpenFlow协议技术及其原理,验证了SDN架构的功能和基本工作流程,构建了网络负载均衡仿真研究的实验环境,并在Mininet中进行了模拟实现,为进一步研究SDN架构提供了有效的技术支撑。     

基于Mininet的SDN仿真与性能分析

SDN(Software Defined Network)是一种创新的网络构架,其核心理念是将控制平面和数据平面分离开来,将网络的管控集中到控制层面。OpenFlow作为南向接口标准提供了控制平面和数据平面分离的可能。文章从SDN的网络构架、SDN的硬件结构和OpenFlow协议对SDN进行了基本的分析,并采用mininet平台构建基于二层学习型交换机的简单防火墙,并对其进行仿真,交换机带宽测试值最高可达到1.09Gbps。     

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.     

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.     

基于SDN的网络虚拟化平台及其隔离性研究

随着云计算的高速发展,虚拟化正成为近年来在企业级环境下广泛应用的技术。除服务器及存储虚拟化外,在SDN和OpenFlow技术的推动下,网络虚拟化成为热点,基于SDN的网络虚拟化平台也应运而生。在分析基于SDN的网络虚拟化设计目标的基础上,对近年来业界推出的4种典型SDN网络虚拟化平台的系统架构和原理进行了对比,并对其安全和隔离性进行了分析总结。     

对基于OpenFlow的SDN技术分析

基于OpenFlow的软件定义网络技术(SDN)技术可以为新的网络应用与未来互联网技术的发展提供支持。本文主要对基于OpenFlow的SDN技术的关键组件、系统架构、OpenFlow的运作模式、基于OpenFlow技术的应用进行了探究,并在此基础上论述了相关领域的研究重点与发展趋势。     

基于OpenFlow网络的流媒体传输QoS的研究与设计

Open Flow是软件定义网络(Software Definded Network,SDN)的产物,是一种新型的网络结构,且发展十分迅速。但Open Flow网络的Qo S功能仍待优化,针对于Open Flow网络中流媒体传输Qo S的不足,在现有网络Qo S模式基础上提出了Open Qo S,它应用于Open Flow网络的控制器上,采用动态路由的方式,使得流媒体在网络端到端传输时,能够根据网络状况,动态改变路由路径,进而提高网络Qo S。最后,通过一个小的拓扑网络对本研究进行了试验验证。     

面向软件定义核心网的OpenFlow分组转发优先制排队模型研究

软件定义网络（Software-Defined Networking,SDN）作为一种数据转发与控制逻辑相解耦、并开放底层编程接口的创新网络架构,为降低核心网的部署运营成本、提升应用业务性能提供了全新的解决思路.然而,在SDN架构下,逻辑上集中的控制平面容易出现性能瓶颈,进而加大分组转发时延,因此有必要理解其分组转发性能特性.为此,本文首先介绍了软件定义核心网的典型部署场景,分析了控制平面的Packet-in消息到达过程和数据平面的分组到达过程,进而应用M/M/n/m和M/M/1/m排队模型分别刻画控制器集群的Packet-in消息处理过程和OpenFlow交换机的分组处理过程.在此基础上,建立OpenFlow分组转发优先制排队模型,进而推导出不同优先级的分组转发时延及其累积分布函数CDF.最后,借助控制器性能测量工具OFsuite_Performance进行实验评估,结果表明：与现有模型相比,本文所提的M/M/n/m模型更能准确估计控制器集群的实际性能.同时,采用数值分析的方法对比了多种情况下不同优先级的分组转发时延及CDF曲线,为软件定义核心网的实际应用部署提供有效参考.     

自治系统内IP子网和SDN子网的互联机制

SDN网络与传统IP网络的互联机制是当前学术界的研究热点,但现有解决方案并不能适用于所有应用场景。为此提出了一个基于OSPF协议的IMISA架构,在一个包含 SDN 子网（基于OpenFlow）和IP子网的自治系统范围内,通过给SDN控制器添加一个OSPF路由模块,利用OSPF协议交换各自的网络信息,最终实现了2种网络的互联。     

基于OpenFIow协议的MSE设备实现方法研究

基于OpenFlow协议与MSE设备的技术原理研究,重点分析OpenFlow 与MSE 实现的关键技术,在对二者进行分析比较的基础上,提出了MSE设备基于OpenFlow协议向SDN架构演进的可行思路。     

SDN特征剖析及典型应用介绍

通过与基于策略的网络管控、软交换等技术的对比,梳理了SDN技术源流,阐述了SDN体系结构及其包含的网络可编程、网络虚拟化等技术思想,剖析了其创新特征和对网络发展的意义;分析了SDN目前还缺乏清晰的商业模式、集中控制器存在状态收集和可伸缩性等问题,指出违背复杂系统管控规律所带来的局限性;介绍了SDN典型应用场景,说明SDN的适用范围主要是在局部自治网络中跨IP网、光网络、无线网络等层面进行一体化管控。     

Mobility management approaches for SDN-enabled mobile networks

The evolving network technologies aim at meeting the envisioned communication demands of future smart cities and applications. Although software-defined networking (SDN) enables flexible network control, its applicability to mobile networks is still in its infancy. When it comes to introducing the SDN vision to mobile networks, handling of wireless events and mobility management operations stand out as major challenges. In this paper, we study the scalability issues of SDNized wireless networks, specifically those relevant to mobility management. We design and implement different mobility management approaches in SDNized wireless networks and investigate the impact of various system variables on the overall handover delays. We also study the improvements in handover delays: (i) when a proposed proactive mobility management algorithm is implemented; (ii) when the controller delegates partial control of mobility management to the forwarding entities. For the implementation of the proposed approaches on the OpenFlow network, the paper also suggests potential extensions to the OpenFlow protocol. The contributed approaches are validated on a full-scale demonstrator, with results showing that proactive outperforms reactive and that the delegated control approach performs better than proactive for smaller topology sizes. Furthermore, a proposal for LTE X2-specific control delegation is discussed as a use case.     

Virtual networks: isolation, performance, and trends

Currently, there is a strong effort of the research community in rethinking the Internet architecture to cope with its current limitations and support new requirements. Many researchers conclude that there is no one-size-fits-all solution for all of the user and network provider needs and thus advocate for a pluralist network architecture, which allows the coexistence of different protocol stacks running at the same time over the same physical substrate. In this paper, we investigate the advantages and limitations of the virtualization technologies for creating a pluralist environment for the Future Internet. We analyze two types of virtualization techniques, which provide multiple operating systems running on the same hardware, represented by Xen, or multiple network flows on the same switch, represented by OpenFlow. First, we define the functionalities needed by a Future Internet virtual network architecture and how Xen and OpenFlow provide them. We then analyze Xen and OpenFlow in terms of network programmability, processing, forwarding, control, and scalability. Finally, we carry out experiments with Xen and OpenFlow network prototypes, identifying the overhead incurred by each virtualization tool by comparing it with native Linux. Our experiments show that OpenFlow switch forwards packets as well as native Linux, achieving similar high forwarding rates. On the other hand, we observe that the high complexity involving Xen virtual machine packet forwarding limits the achievable packet rates. There is a clear trade-off between flexibility and performance, but we conclude that both Xen and OpenFlow are suitable platforms for network virtualization.     

An SDN‐based scalable routing and resource management model for service provider networks

Volume of the Internet traffic has increased significantly in recent years. Service providers (SPs) are now striving to make resource management and considering dynamically changing large volume of network traffic. In this context, software defined networking (SDN) has been alluring the attention of SPs, as it provides virtualization, programmability, ease of management, and so on. Yet severe scalability issues are one of the key challenges of the SDN due to its centralized architecture. First of all, SDN controller may become the bottleneck as the number of flows and switches increase. It is because routing and admission control decisions are made per flow basis by the controller. Second, there is a signaling overhead between the controller and switches since the controller makes decisions on behalf of them. In line with the aforementioned explanations, this paper proposes an SDN‐based scalable routing and resource management model (SRRM) for SPs. The proposed model is twofold. SRRM performs routing, admission control, and signaling operations (RASOs) in a scalable manner. Additionally, resource management has also been accomplished to increase link use. To achieve high degree of scalability and resource use, pre‐established paths (PEPs) between each edge node in the domain are provided. The proposed controller performs RASOs based on PEPs. The controller also balances the load of PEPs and adjusts their path capacities dynamically to increase resource use. Experimental results show that SRRM can successfully perform RASOs in a scalable way and also increase link use even under heavy traffic loads.     

Scalability of software defined network

With the development of software-defined networking (SDN),its scalability has become one of the most important issues of SDN.The features of SDN was studied which lead to its scalability problem when SDN was applied to large-scale network.The three main causes leading to scalability problem were discussed:control plane and data plane separation,logical centralized control and fine-grained flow control.Meanwhile,the studies which focus on the scalability of SDN from three aspects:scalability of performance,scalability of geographic and scalability of control was presented.Further,the studies on the performance evaluation of the scalability of SDN were introduced.Finally,the future work was discussed.