Quality-of-service mapping mechanism for packet video indifferentiated services network

This paper presents a futuristic framework for quality-of-service (QoS) mapping between practically categorized packet video and relative differentiated service (DiffServ or DS) network employing unified priority index and adaptive packet forwarding mechanism under a given pricing model (e.g., DiffServ level differentiated price/packet). Video categorization is based on the relative priority index (RPI), which represents the relative preference per each packet in terms of loss and delay. We propose an adaptive packet forwarding mechanism for a DiffServ network to provide persistent service differentiation. Effective QoS mapping is then performed by mapping video packets onto different DiffServ levels based on RPI. To verify the efficiency of proposed strategy, the end-to-end performance is evaluated through an error resilient packet video transmission using ITU-T H.263+ codec over a simulated DiffServ network. Results show that the proposed QoS mapping mechanism can exploit the relative DiffServ advantage and result in the persistent service differentiation among DiffServ levels and the enhanced end-to-end video quality with the same pricing constraint     

Joint source coding and packet classification for real-time video transmission over differentiated services networks

Differentiated Services (DiffServ) is one of the leading architectures for providing quality of service in the Internet. We propose a scheme for real-time video transmission over a DiffServ network that jointly considers video source coding, packet classification, and error concealment within a framework of cost-distortion optimization. The selections of encoding parameters and packet classification are both used to manage end-to-end delay variations and packet losses within the network. We present two dual formulations of the proposed scheme: the minimum distortion problem, in which the objective is to minimize the end-to-end distortion subject to cost and delay constraints, and the minimum cost problem, which minimizes the total cost subject to end-to-end distortion and delay constraints. A solution to these problems using Lagrangian relaxation and dynamic programming is given. Simulation results demonstrate the advantage of jointly adapting the source coding and packet classification in DiffServ networks.     

实时多媒体服务端到端QoS解决方案

区分服务（Diif-Serv）模型其主要是通过实时多媒体通信数据包进行分类和策略控制来达到调节网络资源的目的，从而实现对实时多媒体服务端到端服务质量QoS。如何时多媒体网络系统中的不同的信息流进行正确的区分服务．然后对不同类别采取不同的服务策略和拥塞管理，从而对网络资源进行有效配置，是实现实时多媒体服务端到端服务质量QoS的关键步骤。文章重点对实时多媒体信息如何进行分类及相应的服务策略和拥塞管理进行时比研究，提出实现端到端QoS服务质量的具体措施和解决方案。并在Cisco思科路由器和交换机建立的DiffSeFV网络环境中进行验证，实验结果表明。对实时多媒体信息进行合理的分类及采用相应服务策略．能很好地实现实时多媒体信息流端到端的服务质量QoS。最后阐述了Diffsenr区分服务存在的问题和未来的发展趋势。     

A Novel Framework for IP DiffServ over Optical Burst Switching Networks

This paper presents a novel framework for IP Differentiated Services (DiffServ) over optical bursts witching (OBS), namely, DS-OBS. The network architecture, functional model of edge nodes and core nodes,the control packet format, a novel burst assembly scheme at ingress nodes and scheduling algorithm of core nodes are presented. The basic idea is to apply DiffServ capable burst assembly at ingress nodes and perform different per hop behavior (PHB) electronic treatments for control packets of different QoS class services at core nodes. Simulation results show that the proposed schemes can provide the best differentiated service for expedited forwarding (EF), assured forwarding (AF) and best effort (BE) services in terms of end-to-end delay, throughput and IP packet loss probability.     

区分服务网络基于测量的接纳控制方案的设计与应用

提出了一种分布式可扩展的接纳控制方案，其目的是为区分服务网络提供端到端服务质量（Quality of Services,QoS)保证，该方案主要由以下部分构成：（1）连接接纳控制协议，主要负责主机和网络节点以及网络节点和带宽代理之间的信息传送，实现对连接请求的串行操作；（2）位于网络核心节点的可用带宽估计算法；（3）位于网络边缘节点的接纳控制算法；给出了该方案在视频传输方面的应用实例；利用多种网络拓扑结构和QoS指标评价该方案的性能，实验结果表明该方案能准确地控制可接纳区域和提高网络资源的利用率。     

IP QoS体系结构

通过对目前正在研究的四类IP QoS协议（RSVP,DiffServ,MPLS,SBM）的详细分析比较发现：虽然它们都能够提供对QoS的支持,但都不能单独成为大规模网络环境下的QoS解决方案,只有对它们的综合应用才能真正实现广域环境下的数据流可预测性传输。以此为基础,给出了大规模网络系统中的IP QoS体系结构。     

IP网络设备中的QoS实现技术

随着IP网络的不断扩大和网络承载业务的不断增加,网络运营商在网络QoS方面的要求在不断提高,由最初的尽力而为和无需QoS保证的网络服务质量要求,逐渐演变到要求运营商提供严格端到端QoS的服务质量保证。本文主要是在基于MPLS的DiffServ网络中,在数据经过IP网络设备时,对QoS实现过程进行分析,并且对比分析了目前QoS在IP网络上实现的几种主要技术,着重对基于MPLS的DiffServ模型网络的DS域边界设备LER和域内设备LSR的QoS实现过程,包括用户识别、流分类、队列调度和拥塞控制等做了全面的论述。     

一种在MPLS网络中提供单流QoS保障的区分服务标记方法*

为了在MPLS网络中提供对单流的高质量服务,提出了一种基于网络的、供应方的区分服务标记方法。在数据流进入网络前按交换路径进行逐点的接入控制,再将许可的资源预留作为流状态安装在入口路由器上。在传输时,数据流在入口路由器按资源预留标记为预留内/预留外,网络节点按不同的标记队列进行区分处理。该方法提出按预留带宽标记数据流,将基于单流的资源预留定量地映射为基于行为聚合的PHB标记,实现了从集成服务到区分服务的融合。其一方面避免了拥塞,提供了对单流的定量服务质量保证;另一方面无须在核心路由器安装流状态和实现流管理,保持了区分服务的可扩展性。     

区分服务网络基于覆盖的拥塞管理方案

提出一种面向区分服务网络确保转发的覆盖式拥塞管理方案,基本思想是利用控制分组在网络的入口和出口节点之间传递网络服务质量的状态信息,入口节点利用加性增加和显性降低的算法调节聚集通信量的发送速率.实验结果表明,与标准的区分服务网络相比,该方案能在聚集之间公平地分配带宽并能显著地降低分组丢失率.     

An end-to-end QoS framework with on-demand bandwidth reconfiguration

This paper proposes a new QoS framework, called the On-Demand QoS Path framework (ODP). It provides end-to-end QoS guarantees to individual flows with minimal overhead, while keeping the scalability characteristic of DiffServ. ODP exercises per-flow admission control and end-to-end bandwidth reservation at the edge of the network and only differentiates service types in the core of the network. In addition, to adapt to dynamically changing traffic load, ODP monitors the bandwidth utilization of the network and performs dynamic bandwidth reconfiguration in the network core based on the monitored bandwidth utilization. Through extensive simulations, the performance of ODP is investigated and compared with that of IntServ and DiffServ frameworks. The simulation results clearly showed that ODP provides end-to-end QoS guarantees to individual flows, which DiffServ can not provide, with much less overhead than IntServ.     

一种基于支持向量回归的互联网端到端延迟预测算法

互联网端到端延迟是指IP分组沿着互联网中一条确定路径进行传输的延迟,端到端延迟的精确预测是大量网络活动的基础,从网络协议设计到网络监测,再从确保端到端QoS性能到各种实时业务性能提升。提出一种新的端到端延迟的预测方法,主要贡献有:a)将互联网端到端延迟预测的问题转换为多元回归的预测问题,提出了基于多元回归的端到端延迟预测框架;b)采用支持向量回归SVR方法来求解端到端延迟的多元回归问题,提出了基于SVR的互联网端到端延迟预测算法。最后使用互联网采集的RTT数据来验证提出的算法,实验结果表明,提出的预测算法具有快速和精确特点,是一种适合实际应用的预测算法。     

Feedback-Based Adaptive Packet Marking for Proportional Bandwidth Allocation

Differentiated service (DiffServ) networks have been proposed to assure the achievable minimum bandwidth to aggregate flows. However, analyses in the literature show that the current DiffServ networks are biased in favor of ah aggregate flow that has a smaller committed information rate (CIR) when aggregate flows with different CIRs share a bottleneck link. In order to mitigate this unfairness problem, we propose an adaptive marking scheme which provides the relative bandwidth assurance in proportion to the CIRs of the aggregates. By introducing a virtual target rate (VTR) and adjusting it depending on the provision level of the network, each aggregate can obtain its fair share of the bandwidth, regardless of traffic load. This scheme is based on a feedback approach. It utilizes only two-bit feedback information conveyed in the packet header and can be implemented in a distributed manner. Furthermore, the proposed scheme does not require calculating fair shares of aggregates or any additional signaling protocol. Using steady state analysis and extensive simulations, we show that the scheme can provide aggregate flows with their fair shares of bandwidth, which is proportional to the CIRs, under various network conditions     

Enhanced bulk scheduling for supporting delay sensitive streaming applications

Providing end-to-end delay guarantees for delay sensitive applications is an important packet scheduling issue with routers. In this paper, to support end-to-end delay requirements, we propose a novel network scheduling scheme, called the bulk scheduling scheme (BSS), which is built on top of existing schedulers of intermediate nodes without modifying transmission protocols on either the sender or receiver sides. By inserting special control packets, which called TED (Traffic Specification with End-to-end Deadline) packets, into packet flows at the ingress router periodically, the BSS schedulers of the intermediate nodes can dynamically allocate the necessary bandwidth to each flow to enforce the end-to-end delay, according to the information in the TED packets. The introduction of TED packets incurs less overhead than the per-packet marking approaches. Three flow bandwidth estimation methods are presented, and their performance properties are analyzed. BSS also provides a dropping policy for discarding late packets and a feedback mechanism for discovering and resolving bottlenecks. The simulation results show that BSS performs efficiently as expected.     

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.     

3G网络服务质量QoS策略及优化

分析了3G网络服务质量QoS控制模式,提出了区别数据流解决带宽分配策略、基于DiffServ模式的数据流优化和基于MQI的流量监管及Qos优化算法,实验证明了方法能减少报文的丢失率,保证通信网络QoS。     

一种基于MPLS保证每流服务质量的方法*

分析了当前网络中保证服务质量的机制,针对目前MPLS本身的服务质量只支持区分服务的现状,提出将动态分组状态模型用于MPLS的方法,通过将状态信息封装在MPLS分组的二层标签中,使核心网络在不需保存每流状态的情况下提供基于每流的服务质量。详细阐述了该方案的总体结构、数据平面和控制平面等,并通过在NS中模拟分析对该方案进行了验证。     

基于区分服务的分层多播拥塞控制算法

多媒体多播应用在Internet上的广泛部署对拥塞控制提出了要求,分层多播是适应网络异构性较为有效的方案.为了克服现有分层多播存在的拥塞响应延时大、吞吐率抖动剧烈和不满足TCP友好的问题,给出了一个基于区分服务的分层多播模型,提出了一种基于区分服务的分层多播拥塞控制算法DSLMCC(DiffServ-based layered multicast packet dropping),在边缘路由器上引入了基于概率的区分优先级的分组标记算法,在核心路由器上采用区分优先级的分组丢弃算法.仿真结果表明,该算法能够有效地改进区分服务网络上的分层多播拥塞控制的性能,具有较快的拥塞响应速度、较好的稳定性和公平性,并且较好地适应了网络的异构性.     

一种基于DiffServ的IP电话QoS实现方案

如何为IP网络中的业务提供QoS保证正成为lP技术所要解决的关键问题。文中基于Diffserv提出了一种IP电话QoS方案，并对其基本思想及实现方法作了详细介绍。该方案将不同的分组数据包设置成不同的优先级，其中系统控制分组数据包优先级最高，语音分组数据包次之，普通数据分组数据包最低，使得系统控制分组和语音分组数据包的平均等待时间缩短。研究结果表明，对不同数据包进行优先级设置是改善IP电话QoS的一种可行方法。     

多媒体传感器网络中服务感知的公平调度算法

针对多媒体传感器网络中基于异常事件驱动的服务模式和基于用户查询驱动的服务模式,分析不同服务的流量模式,提出一种服务感知的公平调度策略,采用基于流量预测的动态公平缓冲共享机制和速率分配算法实现2类数据QoS的公平保障。仿真实验表明,该算法在传输延迟和成功到达率方面实现了公平性目标。     

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。