基于OpenFlow的流量管理研究与设计

随着互联网的快速发展,传统网络的规模不断增长,结构更加复杂,网络管理难度加大,从而导致网络服务质量差。为解决这一问题。文章在SDN的基础上,提出了一种基于Open Flow的网络模型。通过Open Flow控制器控制其交换机中流表实现用户对网络数据处理的可编程控制从而实现了Qo S流量管理,并通过Open Flow控制器Flowlight在mininet中的搭建,验证了其有效性。     

SDN架构下的Open Flow原理探讨

Open Flow是第一个在SDN架构下,规范化控制平面和转发平面之间的通信接口的标准.Open Flow交换机将原来完全由交换机、路由器控制的报文转发过程转化为由Open Flow交换机和控制服务器来共同完成,从而实现了数据转发和路由控制的分离.     

分布式数据库系统动态数据邮递的QoS模型

在信息通讯中传统的单播网络传输,一般采用Dijkstra最短路径算法来建立点到点的最小路径计算。文章针对广域网分布式数据库系统动态、实时数据交换路由问题,对传统的单播网络传输的Dijkstra算法进行改进,提出了一种平衡网络负载的Qo S的路由算法。     

基于OpenFlow的负载均衡研究

Open Flow网络将控制平面与数据平面解耦,通过集中式的控制器来控制整个网络,能够更有效地实现对网络流量的管控。基于Open Flow的负载均衡通过对链路流量进行调度和分配,实现对整个网络流量的负载均衡,能防止网络拥塞、提高网络资源利用率等。但是传统的负载均衡方案难以满足Open Flow网络的全局式、灵活性的要求。因此,需要对Open Flow网络中的负载均衡进行进一步研究,文章提出一种全新的负载均衡解决方案。     

视频监控系统数据在网络中传输与拥塞控制的研究

随着计算机网络和流媒体技术的发展,视频监控系统的网络化进程日益加速。文章对视频监控系统数据在网络中传输的实现进行了研究。构建传输监控系统配置信息和控制数据的WEB服务器,以及用于传输视频数据的RTP服务器。在网络发生拥塞的时候,视频数据在网络中传输就会产生丢包,影响到接收端的视频质量,这就需要在系统中加入视频流的Qo S控制模块。在分析Qo S实现的主要方式之一拥塞控制的基础上,提出码率控制和码率整形相结合的Qo S控制策略,经过在系统上测试,这个策略让人比较满意。     

LTE网络QoS端到端系统控制

进入4G时代,运营商需通过移动管道能力控制,为用户提供差异化服务,从而提高自身价值和利益,因此Qo S端到端控制成为关键;文章首先对EPS网络Qo S原理和架构进行描述,从用户和业务出发,分别介绍了基于用户Qo S签约、基于业务感知以及基于闭环动态Qo S控制这三种端到端Qo S控制策略和业务流程。     

Ad hoc网络中的QoS路由算法

由于 Ad hoc网络自身的特殊性 ,传统的路由协议不能直接用于这种多跳无线网络。迄今为止业界已经设计了多种可行的 Ad hoc路由算法 ,但是对 Ad hoc网络中的 Qo S路由算法的研究才刚刚开始 ,并且面临着巨大的挑战。本文首先阐述了 Qo S路由的概念和目标 ,然后详细讨论了 Ad hoc网络中实施 Qo S路由的难点和可能采用的策略 ,接着介绍了当前相关的研究工作 ,最后指出了今后可能的研究方向     

一种基于OPNET的DiffServ+WLAN网络多媒体端到端QoS性能仿真方法

提出一种基于OPNET的Diff Serv+WLAN网络多媒体端到端Qo S性能验证方法。该方法主要包括网络拓扑搭建和仿真配置两个模块。其中网络拓扑模块主要完成业务在Diff Serv+WLAN网络的传输过程;仿真配置模块的功能是在Diff Serv+WLAN网络拓扑中进行业务参数的配置、收集统计数据等。利用Pro-C高级语言和Visual C++6.0软件搭建Diff Serv与WLAN网络环境,对原网络和加入IPv6流标签的网络进行多媒体业务端到端Qo S性能验证方法仿真,结果表明该方法具有简单、方便等特点。     

基于OpenFlow的SVC流媒体时延自适应分级传输方法

针对当前互联网流媒体传输的时延敏感性问题,提出一种基于OpenFlow的SVC（scalable video coding,可分级视频编码）流媒体时延自适应分级传输方法,该方法有效结合SVC流媒体可分级和OpenFlow灵活可编程的特性,在网络带宽受限和链路拥塞的复杂网络环境下,通过构建基础层和增强层2个独立路由,实现了动态网络下SVC流媒体分级自适应高效传输。仿真结果表明,该方法在提升SVC流媒体传输效率和质量,改善用户体验方面有重要作用。     

基于链路质量的Ad hoc路由协议研究

Ad hoc是近年来热门的无线分组网络。路由协议是Ad hoc网络的关键技术,决定了Ad hoc网络的寻址效率并为数据传输提供可靠的Qo S保证。在小型化网络、低带宽条件下,使用改进的基于链路状态路由协议可以有效的提高寻址效率和网络可靠性。     

An Efficient QoE-Aware HTTP Adaptive Streaming over Software Defined Networking

Due to the increase in video streaming traffic over the Internet, more innovative methods are in demand for improving both Quality of Experience (QoE) of users and Quality of Service (QoS) of providers. In recent years, HTTP Adaptive Streaming (HAS) has received significant attention from both industry and academia based on its impacts on the enhancement of media streaming services. However, HAS-alone cannot guarantee a seamless viewing experience, since this highly relies on the Network Operators’ infrastructure and evolving network conditions. Along with the development of future Internet infrastructure, Software-Defined Networking (SDN) has been researched and newly implemented as a promising solution in improving services of different Internet layers. In this paper, we present a novel architecture incorporating bitrate adaptation and dynamic route allocation. At the client side, adaptation logic of VBR videos streaming is built based on the MPEG-DASH standard. On the network side, an SDN controller is implemented with several routing strategies on top of the OpenFlow protocol. Our experimental results show that the proposed solution enhances at least 38% up to 185% in term of average bitrate in comparison with some existing solutions as well as achieves better viewing experience than the traditional Internet.

     

基于SDN的量子密码通信网络设计与研究

软件定义网络(SDN)采用OpenFlow技术分离网络设备的数据平面和控制平面,实现灵活控制网络资源的目的。基于此,设计了量子密码通信网络模型,实现灵活控制密码通信网络整体量子密匙资源,确保了信息的安全传输。此外,提出了综合到端可用密匙和跳数的路由算法,提高了QKD生成密匙的有效利用率。由测试结果可知,通过基于SDN的量子密码通信网络及路由算法,可提高量子密匙资源利用率,提高网络性能。     

一种基于软件定义网络的自治服务质量管理机制(英文)

With the increase of network complexity,the flexibility of network control and management becomes a nontrivial problem.Both Software Defined Network(SDN) and Autonomic Network technologies are sophisticated technologies for the network control and management.These two technologies could be combined together to construct a software defined self-managing solution for the future network.An autonomic QoS management mechanism in Software Defined Network(AQSDN) is proposed in this paper.In AQSDN,the various QoS features can be configured autonomically in an OpenFlow switch through extending the OpenFlow and OF-Config protocols.Based on AQSDN,a novel packet context-aware QoS model(PCaQoS) is also introduced for improving the network QoS.PCaQoS takes packet context into account when packet is marked and managed into forwarding queues.The implementation of a video application's prototype which evaluates the self-configuration feature of the AQSDN and the enhancement ability of the PCaQoS is presented in order to validate this design.     

QoS‐aware routing and power control algorithm for multimedia service over multi‐hop mobile ad hoc network

This paper presents a QoS (quality of service) aware routing and power control algorithm consuming low transmission power for multimedia service over mobile ad hoc network. Generally, multimedia services need stringent QoS over the network. However, it is not easy to guarantee the QoS over mobile ad hoc network since its network resources are very limited and time‐varying. Furthermore, only a limited amount of power is available at mobile nodes, which makes the problem more challenging. We propose an effective routing and power control algorithm for multimedia services that satisfies end‐to‐end delay constraint with low transmission power consumption. The proposed algorithm supports the required bandwidth by controlling each link channel quality over route in a tolerable range. In addition, a simple but effective route maintenance mechanism is implemented to avoid link failures that may significantly degrade streaming video quality. Finally, performance comparison with existing algorithms is presented in respect to traditional routing performance metrics, and an achievable video quality comparison is provided to demonstrate the superiority of the proposed algorithm for multimedia services over mobile ad hoc network. Copyright © 2010 John Wiley & Sons, Ltd.     

Hybrid QoS based routing protocol for inter and intra wireless mesh infrastructure communications

Quality of service (QoS) in wireless mesh networks is an active area of research, which is driven by the increasing demand for real-time and multimedia applications, such as Voice over IP and Video on Demand. In this paper, we propose a novel QoS based routing protocol for wireless mesh infrastructure, called Hybrid QoS Mesh Routing (HQMR). It is composed of two QoS based routing sub-protocols: a reactive multi-metric routing protocol for intra-infrastructure communications and a proactive multi-tree based routing protocol for communications with external networks. The proposed routing protocol enables forwarding real-time and streaming applications with QoS guarantee in a mesh wireless environment, by assigning a specific routing path for each defined service class. To this end, three different QoS service classes are defined, depending on the applications requirements. We analyze in this paper the simulation results of different scenarios conducted on the network simulator ns-3 to demonstrate the effectiveness of the HQMR protocol and to compare it to other routing protocols while forwarding real-time applications with QoS guarantee.     

一种流媒体拥塞控制算法在NS-2中仿真实现及结果分析

NS(Network Simulator)是一个面向对象的离散事件模拟器,它可以对复杂网络环境中数据传输、拓扑结构设计以及新的路由协议和算法等进行有效模拟和分析。该文首先阐述了NS的体系结构特点及利用NS进行网络仿真的一般方法和步骤,并实现了一种基于流媒体应用的自适应拥塞控制算法的实例,并对其仿真结果进行了分析。实验结果表明,当网络中产生拥塞时,其延迟、时延抖动和吞吐量会发生相应变化的客观现象。     

QoS-aware multi-path video streaming for urban VANETs using ACO algorithm

Drivers can be provided with several beneficial services associated with video streaming in a vehicular ad-hoc network (VANET). Given the dynamic topology and high mobility of VANETs, a single path cannot support the required quality of service (QoS). To maximize global QoS metrics, a two-path model is proposed based on a disjoint algorithm to forward sub-streams over diverse paths from the transmitter to the receiver vehicle. In this solution, the video information spread in separate paths is categorized based on their priority. For this purpose, the protocol for transmitting each kind of video data should be selected cautiously. The present study aims to propose an ant colony optimization-based technique to establish the primary and secondary paths and enhance the QoS of routing paths. To achieve this goal, the QoS routing issue is formulated mathematically as a problem of constrained optimization. Moreover, to achieve high-quality video streaming, inter-frames are transmitted over the user datagram protocol and intra-frames are transmitted over the transmission control protocol (TCP). TCP transmission delays are also minimized using a TCP-ETX algorithm for selecting appropriate paths. According to the simulation results, the proposed two-path solution can be used to improve the quality of video streaming and to enhance the performance in terms of end-to-end delay, packet delivery ratio, and overhead. In this way, the proposed method can outperform several prominent routing algorithms such as adaptive QoS-based routing for VANETs, geographic source routing (GSR), intersection-based geographical routing protocol, and efficient GSR.

     

安全保障：无线Mesh网络中支持QoS的DSR路由协议的改进与实现

随着无线Mesh网络传输多媒体业务需求的增加,要求网络支持服务质量（QoS）,本文基于DSR协议设计了一个支持QoS的路由协议算法QDSR（QoS-DSR）。该算法保证了数据流的带宽、时延的QoS需求,根据路径跳数和节点拥塞情况定义路由代价函数,选择最优路径。仿真结果表明,与DSR相比,QDSR提高了网络吞吐量,降低了平均端到端延时,提高了网络利用率,更好地满足业务的QoS需求,并且具有更强的适用性和可扩展性。     

基于图卷积神经网络的软件定义电力通信网络路由控制策略

传输时延和数据包丢失率是电力通信业务可靠传输重点关注的问题,该文提出一种面向软件定义电力通信网络的最小路径选择度路由控制策略。结合电力通信网络软件定义网络(SDN)集中控制架构的特点,利用图卷积神经网络构建的链路带宽占用率预测模型(LBOP-GCN)分析下一时刻路径带宽占用率。通过三角模算子(TMO)融合路径的传输时延、当前时刻的路径带宽占用率和下一时刻的路径带宽占用率,计算出从源节点到目的节点间不同传输路径的选择度(Q),然后将Q值最小的路径作为SDN控制器下发的流表项。实验结果表明,该文所提出的路由控制策略能有效减小业务传输时延和数据包丢失率。