SDN中一种基于拓扑变换的功能组合方法

现有软件定义网络(SDN)中的功能组合方法大多都在单节点内进行,均未考虑单节点交换机的功能承载力.为此,首先提出一种基于拓扑变换的功能组合方法,通过拓扑变换将功能组合分散到多个节点中进行处理.其次,将拓扑变换建模成0-1线性规划问题并提出了综合搜索算法进行求解.最后,基于NetFPGA-10G和Ryu控制器完成了所提功能组合方法的原型系统实现.实验结果表明,与现有方法相比,所提出的功能组合方法在降低流处理时延和存储开销的同时提高了组合效率.     

MTS:基于多级流表技术的OpenFlow控制器架构

基于多级流表技术提出一种新型OpenFlow控制器架构MTS,MTS有效地利用多级流表的能力,并充分体现了面向服务的设计思想,基于MTS实现简单的原型系统,为模型的可行性提供有力支持。     

一种基于多级流表的中间件服务链的部署方法

为了解决服务链部署中的路径循环和源地址绑定问题,首先,提出一种新的服务链部署方法,该方法利用OpenFlow多级流表标识服务链及服务顺序,从而使数据分组按照需求的服务顺序正确处理;其次,提出服务链部署算法以实现服务路径到流表规则的映射;最后基于NetFPGA-10G完成了原型系统实现。仿真结果表明,该部署方法具备可行性,并降低了流表数量和时间开销。     

USB接口的DVB码流播放器设计与实现

提出了一种基于USB的数字视频码流播放器设计方案,实现了DVB码流的PC处理和传输.该方案采用内嵌微处理器的USB2.0芯片作为接口控制器,选择FPGA作为主时序控制器,测试结果证明能满足高速码流实时可靠传输的要求.     

基于属性加密的组合文档安全自毁方案

为保护组合文档全生命周期的隐私安全,提出了一种基于属性加密的组合文档安全自毁方案.该方案引入多级安全思想创建新的组合文档结构,采用访问密钥加密组合文档内容、基于属性的加密算法加密访问密钥,两者的密文经过一系列算法提取和变换后获得密文分量和封装自毁对象,分别存储在两个分布式哈希表网络和云服务器中.当组合文档过期后,该网络节点将自动丢弃所存密文分量,使得原始组合文档密文和访问密钥不可恢复,从而实现安全自毁.安全分析表明,该方案既能抵抗传统的密码分析或蛮力攻击,又能抵抗分布式哈希表网络的Sybil攻击.     

高速遥感图像压缩系统ZBT SRAM控制器的设计

针对高速遥感图像数据源的特点,提出了基于FPGA片外ZBT SRAM的双缓冲方案,并实现了ZBTSRAM控制器.该控制器提供FPGA与两片ZBT SRAM之间的接口,通过乒乓操作实现了对高速数据流的无缝缓冲与处理,为压缩处理模块提供了符合流水线算法要求的输入数据.本设计基于Altera公司的Stratix系列FPGA实现,并已在实际中通过验证,满足功能和时序要求.     

基于SDN的多控制器部署策略的研究

随着SDN在大型网络以及广域网中的需求,如何合理、高效地部署SDN控制器,从而以较低的部署成本,获得较好的网络性能,是当前研究的热点.针对控制器数量、部署位置问题以及交换机与控制器之间的映射关系的问题,首先给出一种分布式的控制器部署方式并设定了网络相关参数,以流建立请求代价为优化目标,提出了一种基于贪心算法的控制器部署策略方案.最后通过仿真实验将所提出方案与ACL方案进行对比,证明了所提方案在性能方面有一定的提升.     

基于Zynq7020的组合导航处理平台软硬件系统的设计与实现

提出一种基于Zynq处理平台的组合导航系统设计及实现方案,Zynq7020作为新近发展的可扩展处理平台,集成了大规模可编程逻辑器件(FPGA)、低功耗高性能先进ARM处理器,两者通过内部总线互联与通信,满足高集成度、高性能数据处理的应用需求.基于Zynq处理器设计并实现组合导航处理平台,替代原有的FPGA+DSP+ARM导航解算模式,单芯片完成IMU信号采集,信号处理和导航解算等功能,降低整机设计的复杂度和成本.     

基于网络化技术的电机控制系统设计

设计了基于网络化技术的电机控制与测量系统方案.给出系统硬件组成,实现6路PWM控制通道,5路电机速度检测通道,并通过SPI接口与NETCON控制器完成通信.解决了对电机控制系统多路电机中任一路电机的转速与相位的实时监控,实现了单片机与ARM系列处理器之间的通信.此电机控制系统与嵌入式网络化控制器组合于一体能够完成对水箱、数控机床、机械手等模型的控制.     

基于SDN的QoS管理机制研究

随着互联网的发展,媒体流的数目逐渐增多。由于受到传统网络架构的限制,已经很难对这些流进行灵活控制与管理。SDN的出现为解决此问题提供了新的思路。文章提出了一个基于SDN的QoS管理方案,使用阻塞队列对不满足传输条件的流进行管理。当有流到达时,首先判断是否有满足流约束条件的路径。如果拥有,控制器下发流表进行流的传输;如果没有,控制器将流加入阻塞队列。当有流完成传输时,控制器及时调度阻塞队列中的流。文章对方案进行了优化,为QoS流选择路径时增加了时延抖动参数,能够排除一些时延不稳定的路径,及时对流进行调度,增加了链路资源的利用率。     

SDN应用及北向接口技术研究

SDN北向接口是通过控制器向上层业务应用开放的接口,其目标是使得业务应用能够便利地调用底层网络资源和能力。文章首先介绍SDN北向接口的功能、分类及实现案例;进而以云计算资源管理平台为例分析SDN应用;最后在OpenStack开源框架下提出虚拟机迁移网络策略同步跟随场景的实现方案。     

基于元能力的SDN功能组合机制

软件定义网络（SDN, software-defined network）促进了控制逻辑的快速创新,使控制逻辑模块化和模块组合机制成为SDN的热点研究方向之一。为了在功能模块统一定义和规范划分的基础上实现网络功能组合,首先,从可重构网络引入“元能力”作为SDN控制功能模块划分的原子要素,提出一种基于元能力建模的统一资源描述方法;其次,针对网络功能灵活组合问题,提出了一种基于二级映射的元能力组合模型并给出其启发式算法;最后,为实现元能力组合,设计了作为SDN应用层扩展结构的元能力编排层,并给出基于NetFPGA-10G平台的原型实现。仿真实验与结果表明所提功能组合机制提高了组合效率及节点资源利用率。     

Self-healing and SDN: bridging the gap

Achieving high programmability has become an essential aim of network research due to the ever-increasing internet traffic. Software-Defined Network (SDN) is an emerging architecture aimed to address this need. However, maintaining accurate knowledge of the network after a failure is one of the largest challenges in the SDN. Motivated by this reality, this paper focuses on the use of self-healing properties to boost the SDN robustness. This approach, unlike traditional schemes, is not based on proactively configuring multiple (and memory-intensive) backup paths in each switch or performing a reactive and time-consuming routing computation at the controller level. Instead, the control paths are quickly recovered by local switch actions and subsequently optimized by global controller knowledge. Obtained results show that the proposed approach recovers the control topology effectively in terms of time and message load over a wide range of generated networks. Consequently, scalability issues of traditional fault recovery strategies are avoided.     

A low latency service function chain with SR-I/OV in software defined networks

A network flow is required to be processed by multiple network functions such as PGW and SGW in mobile networks as a service function chain (SFC). Compared to hardware-based network functions, virtualized network functions are more flexible for deployment. Software defined network (SDN) provides a centralized network architecture to manage network resources and route the network flow among network functions in sequence and virtual machines are leveraged to deploy the network functions as network function virtualization (NFV). However, currently the performance of NFV suffers from I/O latency because packet processing causes lots of interrupts that decreases CPU utilization. To address the I/O latency issue, SR-I/OV network card is designed to replace OpenvSwitch in host machines to reduce the system interrupts. However, SR-I/OV is not compatible with existing SDN system, which is an important component in future 5G networks. Therefore, we propose an integrated architecture called the low latency service function chain from a wider perspective in system design to overcome main defects described above. We modify appropriate components in SR-I/OV driver and OpenvSwitch to dramatically reduce packet processing latency in SFC composed by several VNFs. Moreover, our design is compatible with SDN environment and benefited by central control.

     

软件定义网络中基于密码标识的报文转发验证机制

针对软件定义网络(SDN)中缺乏安全高效的数据来源验证机制问题,该文提出基于密码标识的报文转发验证机制。首先,建立基于密码标识的报文转发验证模型,将密码标识作为IP报文进出网络的通行证。其次,设计SDN批量匿名认证协议,将SDN控制器的验证功能下放给SDN交换机,由SDN交换机进行用户身份验证和密码标识验证,快速过滤伪造、篡改等非法报文,提高SDN控制器统一认证与管理效率,同时可为用户提供条件隐私保护。提出基于密码标识的任意节点报文抽样验证方案,任何攻击者无法通过推断采样来绕过报文检测,确保报文的真实性的同时降低其处理延迟。最后,进行安全性分析和性能评估。结果表明该机制能快速检测报文伪造和篡改及抵抗ID分析攻击,但同时引入了大约9.6%的转发延迟和低于10%的通信开销。     

ONVisor: Towards a scalable and flexible SDN‐based network virtualization platform on ONOS

Network virtualization (NV) technologies have attracted a lot of attention as an essential solution for future networking infrastructure. The NV enables multiple tenants to share the same physical infrastructure and to create independent virtual networks (VNs) by decoupling the physical network in terms of topology, address, and control functions. One feasible way to realize full NV involves considering solutions based on the software‐defined networking (SDN) paradigm using its programmability. The SDN contributes many benefits to both network operations and management including programmability, agility, elasticity, and flexibility. There are several SDN‐based NV solutions; however, they suffered from a lack of scalability, high availability. Also, they have high latency between control and data plane because of proxy‐based architecture. In this thesis, we introduce a new NV platform, named Open Network Hypervisor (ONVisor). The design objectives include, among the features, (1) multitenancy, (2) scalability, (3) flexibility, (4) isolated VNs, and (5) VN federation. ONVisor was designed and implemented by extending Open Network Operating System, an open‐source SDN controller. The main features of ONVisor are (1) isolated control and data plane per VN, (2) support of distributed operations, (3) extensible translators, (4) on‐platform VN application development and execution, and (5) support of heterogenous SDN data‐plane implementations. Several experiments are conducted on various test scenarios in different test environments in terms of control and data plane performance compared to nonvirtualized SDN network. The results show that ONVisor can provide VNs a little bit lower control plane performance and similar data plane performance.     

Separating VNF and Network Control for Hardware‐Acceleration of SDN/NFV Architecture

A hardware‐acceleration architecture that separates virtual network functions (VNFs) and network control (called HSN) is proposed to solve the mismatch between the simple flow steering requirements and strong packet processing abilities of software‐defined networking (SDN) forwarding elements (FEs) in SDN/network function virtualization (NFV) architecture, while improving the efficiency of NFV infrastructure and the performance of network‐intensive functions. HSN makes full use of FEs and accelerates VNFs through two mechanisms: (1) separation of traffic steering and packet processing in the FEs; (2) separation of SDN and NFV control in the FEs. Our HSN prototype, built on NetFPGA‐10G, demonstrates that the processing performance can be greatly improved with only a small modification of the traditional SDN/NFV architecture.     

基于深度动态贝叶斯网络的服务功能链故障诊断算法

针对5G端到端网络切片场景下底层物理节点出现故障会导致运行在其上的多条服务功能链出现性能异常的问题,该文提出一种基于深度动态贝叶斯网络(DDBN)的服务功能链故障诊断算法。首先根据网络虚拟化环境下故障的多层传播关系,构建故障与症状的依赖图模型,并采用在物理节点监测其上多个虚拟网络功能相关性能数据的方式收集症状。其次,考虑到基于软件定义网络(SDN)和网络功能虚拟化(NFV)的架构下网络症状观测数据的多样性以及物理节点和虚拟网络功能的空间相关性,引入深度信念网络对观测数据特征进行提取,使用加入动量项的自适应学习率算法对模型进行微调以加快收敛速度。最后,利用故障传播的时间相关性,引入动态贝叶斯网络对故障根源进行实时诊断。仿真结果表明,该算法能够有效地诊断故障根源且具有良好的诊断准确度。     

自防御网络中客户端Agent的研究与实现

主要研究自防御网络计划中的网络准入控制功能。介绍自防御网络的概念、功能以及处于自防御网络最前端的部分-客户端Agent的功能;自防御网络系统的设计方法。重点介绍客户端Agent的设计以及其各个组成模块的功能、设计方法。最后搭建测试环境并进行测试,测试结果均达到预期的效果。     

Dynamic control plane management for software‐defined networks

Software‐defined network (SDN) is an emerging network paradigm that allows flexible network management by providing programmability from a separated control plane. Because of the centralized management scheme that SDN adopts, intensive control plane overhead incurs as the scale of SDN increases. The control plane overhead is mainly caused by a massive amount of control messages generated during data plane monitoring and reactive flow instantiation. By far, very few works have addressed the overhead issue on reaction flow instantiation; therefore, we mainly focus on alleviating such overhead in this work. To achieve this goal, we propose a new control plane management (CPMan) method. CPMan aims to realize the following two objectives: first, reduce the number of control messages exchanged through the control channel and second, evenly distribute the control workload across multiple controllers to mitigate the potential performance bottleneck. To realize the former, we propose a lightweight feedback loop‐based control scheme, whereas for the latter, we propose a dynamic switch‐to‐controller (DSC) placement scheme. To show the feasibility of our proposal, we implemented a prototype of the two proposed schemes on top of a carrier‐grade SDN controller and validated its performance in an emulated network. We achieved approximately 57.13% overhead reduction with feedback loop‐based control scheme, while achieved approximately 98.68% balance ratio with DSC placement scheme. Copyright © 2016 John Wiley & Sons, Ltd.