一种支持DiffServ模型的全分布式调度算法

调度算法设计对于网络路由设备实现区分服务(DiffServ)模型的单跳行为(per hop behavior,简称PHB)至关重要.现有支持DiffServ模型的调度算法普遍基于输出排队(output queued,简称OQ)或是输入排队(input queued,简称IQ)交换结构进行设计,均无法在高速环境下提供高性能的调度.基于联合输入/交叉节点排队(combinedinput-crosspoint-queued,简称CICQ)交换结构提出一种支持DiffServ模型的全分布式调度算法DDSS (distributed DiffServ supporting scheduling),并通过理论分析对其公平性进行了验证.DDSS算法采用基于预约带宽的逐级流量控制机制实现所有预约带宽在快速转发(expedited forwarding,简称EF)业务与确保转发(assured forwarding,简称AF)业务之间的分配,采用优先级调度机制为EF业务提供低延迟服务,算法复杂度为O(log N).仿真结果表明,DDSS算法具有良好的时延性能和公平特性,与现有算法相比,能够更好地支持DiffServ模型.     

基于DiffServ模型的调度算法

区分服务(DiffServ)模型中不同队列调度算法对网络性能有不同的影响。该文介绍了DiffServ实现模型,分析比较了目前4种典型队列调度算法的基本原理及性能特点。基于OPNET Modeler构建了采用不同调度算法的DiffServ仿真实现模型,通过对各仿真结果的比较研究,进一步验证了几种算法各自的优劣特性。     

区分服务在Linux上的实现

本文给出了Linux流量控制的基本元素的简单介绍，并解释了如何把现有的体系结构加以扩展以支持Diff-Serv。接着，说明了如何使用Linux当前内核里的流量控制的结构来实现Linux支持DiffServ机制。具体地给出了新的组件，分类器，标记器和基于随机早期检测的jjjPHB。我们还描述了该模型的整体结构。     

OPNET环境下DiffServ机制的仿真

介绍了DiffServ机制的体系结构和基本机制,并建立了基于OPNET环境下的仿真模型。通过对DiffServ机制的4种转发类型进行仿真,收集仿真结果。通过分析结果研究不同服务级别设置对其QoS性能的影响。     

基于连接的SLA流量标记方案及实现

区分服务(DiffServ)使得服务供应商(SP)能够提供满足更严格、更全面的服务等级协定(SLA)的IP服务性能.方法之一,就是让设计者在设计IP骨干网时能够确保SLA参数满足每一类业务需求.其中如何有效地对已识别的流量进行标记,是一个难点.基于Linux DiffServ环境,设计并实现了一种基于连接状态的SLA流量标记方案.实验证明该方案具有良好的性能要求,可以作为ISP工程应用的一个参考模型.     

区分服务中每跳行为的一种实现方案

区分服务体系结构 (简称DiffServ) ,作为一种互联网服务质量的解决方案 ,具有较好的可扩展性和健壮性。DiffServ中 ,其每跳行为 (PHB)的实现是关键。该文提出的PHB实现方案主要包括 :①采用类似最大队长和最小分配共享的DiffServ缓冲分配策略 ,进行队列间的缓冲区分配 ;②选用交错方式的RIOC策略进行队列管理 ;③使用一种新的调度算法———PRI/FWRR ,来进行队列调度。并通过计算机仿真说明 ,该方案能够满足DiffServ中各类PHB的特性要求     

DiffServ和MPLS相结合的流量工程机制

MPLSTE对传统的流量工程进行扩展,实现端到端的QoS保证,但是以流量中继为服务粒度。对流量缺乏区分服务的能力。DifIServ模型提供了区分服务,但是缺乏端到端的QoS有效路由策略。通过将MPLSTE的有效路由策略和DiffServ的区分服务相结合,引入区分服务感知的流量工程．运用带宽约束模型,在网络中实现端到端区分服务的QoS保证。     

DiffServ over MPLS解决方案研究

介绍QoS模型DiiiServ及其实现,通过DiffServ对网络中的通信流量进行分类和策略控制来达到调节网络资源的目的.分析MPLS技术及其实现原理,将灵活的三层IP路由和高速的二层交换技术完美地结合起来;探讨了实现Dillserv与MPLS相结合的DiffServ over MPLS模型,从而实现网络中通信流量的QoS保证.     

基于MPLS的下一代网络QoS模型

介绍集成服务、区分服务、流量工程和MPLS几种常用的服务质量(QoS)技术,任何一种独立的技术都不能很好地解决QoS问题。该文提出一种将流量工程引入多协议标签交换(MPLS)网络并结合DiffServ和IntServ的QoS模型,阐述其原理及部分实现技术,利用NS2工具对提出的网络模型进行仿真。结果表明,与单纯的MPLS网络相比,该模型改善了网络延时,丢包率降低20%。     

基于漏斗模型的生产计划与控制方法

本文介绍了一种新的生产调度方法──基于漏斗模型的生产计划与控制方法，讨论了流量图模型描述方法，面向负荷的订单投放方法等一些重要的概念和技术，并且介绍了一个基于此方法的生产调度万法仿真模型系统。     

FIAC: a resource discovery-based two-level admission control for differentiated service networks

Differentiated Service (DiffServ) architecture has been proposed as a scalable QoS architecture for Internet. DiffServ, however, could not control its loads under heavy traffic conditions, and it could not provide strong QoS responses for individual traffic flow. This paper introduces at the edges of a DiffServ domain, a novel two-level admission control scheme, the Fair Intelligent Admission Control (FIAC). At per-class level, FIAC admits traffic according their fairshare and usage while preventing possible congestion within the DiffServ core. At per-flow level, FIAC estimates and allocates the fairshare for each flow within a class.

Simulation results demonstrate that FIAC adheres extremely well to the bandwidth requirements of DiffServ classes while preventing congestion within the DiffServ core. With FIAC's per-flow level enabled, FIAC is able to prevent uncontrolled UDP flows from depriving TCP-controlled flows of bandwidth share when they are aggregated to the DiffServ domain.     

基于Linux流控机制的QoS网络

对Linux内核中的流控机制进行剖析，以区分服务(DiffServ)模型为侧重点，根据区分服务模型的体系结构，提出了利用Linux流控机制实现加速转发逐跳行为的应用方案。实验表明，该方案适合于QoS网络的构建。     

A measurement-based approach for dynamic QoS adaptation in DiffServ networks

This paper presents a practical approach to managing multimedia traffic in DiffServ network, using network monitoring feedback and control. We exploit the flexibility of multimedia traffic and process network level parameters to adapt the traffic according to the current state of the network. The latter is determined based on reports sent by bandwidth monitors installed on each node of a DiffServ Domain. The bandwidth monitors interact with a policy server which, depending on the network state, decides the policy(ies) that should be enforced by the DiffServ network. The implementation of the selected policies typically leads to accepting, remarking, or dropping the multimedia traffic entering the network. Multimedia streams may be assigned different levels of QoS, as interpreted by the marker at the DiffServ edge router and marked according to network state. To achieve such dynamic QoS adaptation for multimedia applications, we have implemented and evaluated a policy-based management system. Performance evaluation shows that multimedia applications adapt better to network conditions using our approach.     

一种区分服务网络的设计与实现

给出了DiffServ网络的一种设计与实现，提出了一种有效的资源管理模型。在该模型中，存在一个带宽代理(Bandwidth Broker)同步多个边界节点的接纳控制，负责区分服务网络之间的SLA(Server Level Agreement)协商，进行路由器配置；边界节点使用RSVP协议为集聚流预留资源；RSVP使用预计算QoS路由寻找路径。整个模型不仅综合了已有资源管理方案的优点，而且保持了区分服务网络的可扩展性。     

大型校园网QoS保障策略实现研究

本文比较了传统IP网络的QoS体系结构,通过分析IntServ和DiffServ两种模型的基本原理、工作方式,并指出其各自的优缺点和网络应用环境,设计了将扩展RSVP协议与DiffServ模型相结合的策略来保障大型校园网QoS的实现。仿真测试结果表明,此模型的应用可以有效地提升大型校园网络的QoS。     

Rate adaptive shaping for the efficient transport of data traffic in diffserv networks

In this paper, we introduce the need for traffic shaping for the efficient transport of aggregate Internetworking traffic over Differentiated Services (DiffServ) networks. We propose a family of rate adaptive shapers (RASs) that aim at reducing the traffic burstiness. Although RASs can be used in either pure Best-Effort or any QoS enabled networks, our study is focused on their use in DiffServ networks where the traffic is subject to traffic control consisting of marking the packets according to a pre-negotiated traffic conditioning specification. RASs aim to increase the ratio of packets that are assigned the highest level of forwarding treatment by buffering and appropriate scheduling of packets before applying traffic control functions. The key ideas that motivate RASs design are introduced and evaluated by means of extensive simulations. Some additional enhancements are also discussed.     

基于IEEE802.11e和DiffServ的端到端QoS结构

研究了从无线到有线网的基于IEEE802.11e和DiffServ（区分服务）的端到端的QoS结构，介绍了802.11e、802.1D／Q和DiffServ的特点，并就它们之间的优先级映射进行了分析，从流量分类、标记、整形方面对IEEE802.11e和DiffServ的QoS参数提出了分级的接口。     

基于IEEE802.11e和DiffServ的端到端QoS结构

研究了从无线到有线网的基于IEEE802.11e和DiffServ(区分服务)的端到端的QoS结构，介绍了802.11e、802.1D/Q和DiffServ的特点，并就它们之间的优先级映射进行了分析，从流量分类、标记、整形方面对IEEE802.11e和DiffServ的QoS参数提出了分级的接口。     

Monitoring Edge-to-Edge Traffic Aggregates in Differentiated Services Networks

Differentiated Services (DiffServ), which are currently being standardized in the IETF DiffServ working group, is a solution that can provide different qualities of service to different network users. DiffServ aggregates network packets at edge routers and forwards the aggregated packets to core routers with different priorities. In this paper, we propose methods using the SNMP framework for monitoring edge-to-edge traffic aggregates in a DiffServ domain, which consists of a set of DiffServ-enabled routers. In order to manage each DiffServ router, we have analyzed the DiffServ MIB and instrumented it in the router. Further, we propose monitoring behaviors of edge-to-edge traffic aggregates by combining topology and performance information from MIB II and DiffServ MIB. Construction procedures and graphical representation of the edge-to-edge traffic aggregates are explained in detail. We also extend our efforts to implement a DiffServ domain monitoring system that monitors a set of DiffServ-enabled routers and traffic aggregates between every edge router pair. We believe that the proposed monitoring methods can serve as useful building blocks for managing DiffServ networks.