【作者】 王婷；

【导师】 兰巨龙；

【作者基本信息】 解放军信息工程大学 ， 通信与信息系统， 2007， 硕士

【摘要】 各种流媒体业务的不断涌现,使得传统IP网络“尽力而为”的服务模式越来越不能适应新型业务的传输需求,宽带流媒体业务对边缘网架构的演进提出了新要求,作为边缘网与骨干网接入点的路由器就成为保证用户端到端服务质量的关键单元。本文以ACR EMD中流量管理技术的研究与实现为课题目标,提出了一种支持区分优先级的流量管理机制并予以工程实现。该机制通过队列管理算法保证了不同优先级业务的区分丢包,通过队列调度算法保证了不同优先级业务的服务质量要求。单板测试结果表明该机制达到了ACR用户流量管理的要求。本课题主要包含如下几方面工作;1.通过对已有流量测量、队列管理及队列调度算法的分析比较,针对ACR的应用需求提出了一种具有良好可扩展性的区分优先级流量管理(DPTM)机制。DPTM机制由区分丢包随机早期丢弃fDDPRED)队列管理算法和基于优先级的并行分布式双调度加权轮询(PDDWRR)队列调度算法协同完成,不仅可为高优先级业务提供低时延服务,而且可为低优先级业务提供公平的输出带宽。2.提出一种DDPRED队列管理算法,该算法为不同优先级业务设置不同的丢弃门限实现了区分优先级的包丢弃。通过对DDPRED算法数学模型的分析,给出了门限参数与丢包率及时延的函数关系,工程实现中可根据实际丢包率及时延要求灵活设置门限参数。3.提出一种可支持变长包处理的PDDWRR队列调度算法,该算法采用双调度指针和两种优先级模式为不同优先级业务提供更细颗粒度的服务质量。通过对二维马尔可夫链典型模型的分析证明该算法可为低优先级业务提供公平的输出带宽保护,性能仿真表明PDDWRR算法的低优先级业务的丢包率及高优先级业务时延要优于DRR算法。4.结合项目需求给出了ACR EMD中DPTM机制的硬件实现方案。DPTM机制的并行分布式虚拟优先级队列(VPQ)结构支持流水线调度,对于10Gbps的端口速率可实现数据包的线速处理。单板测试结果表明;DPTM机制完全满足ACR用户上、下行业务流量管理的要求。更多还原

【Abstract】 Along with various Streaming Media business emerging, "Best Effort" mode of traditional IP network can not meet the demands of new businesses, and Broadband Streaming Media business will ask for the evolution of Edge network structure. Router must afford end-to-end QoS, as the access point of Backbone network and Edge network.This dissertation based on the research and implement of traffic management technology on ACR EMD, and brought forward a traffic management mechanism supported different priority. It is assured of different drop possibility of different priority business by queue management, and assured of different QoS demand for different business by queue schedule.The main work and contributions in this dissertation are outlined as follows:1. Analyzing and comparing some mature arithmetic such as traffic measurement, queue management and queue schedule, this thesis put forward a traffic management mechanism named DPTM with good scalability, which is aimed at application demand. This mechanism is composed of DDPRED queue management arithmetic and PDDWRR queue schedule arithmetic. It ensured low delay of high-priority business and fair output bandwidth of low-priority business.2. Proposed DDPRED queue management arithmetic. It is used for different dropout rate of different business by setting different threshold. The function relations between threshold and dropout rate and delay is concluded, so we can set threshold flexibly in engineering according to the requirements of dropout rate and delay.3. Proposed PDDWRR queue schedule arithmetic that can support variable-length packets. Based on double schedule guidelines and two priority modes, this arithmetic will provide fine-partical QoS for different businesses. The planar Markov chain analysis of PDDWRR proved that it is justice in output bandwidth distribution for low-priority business. The simulation results shows that low delay of high-priority business and fair output bandwidth of low-priority business of PDDWRR are better than DRR.4. Aimed at project requirements, this dissertation presented hardware implement program of DPTM mechanism on ACR EMD. The structure of parallel distributed VPQ can support pipelining schedule, so DPTM mechanism can processed packet within wire speed for 10Gbps port. The test results of GE board shows that DPTM mechanism completely satisfied the demand for traffic management of uplink and downlink user’s businesses on ACR.更多还原