基于网络处理器的DiffServ边界路由器研究与实现

DiffServ体系由于其良好的可扩展性在QoS中得到了广泛的应用。但基于GPP和ASIC的传统网络解决方案由于不能兼顾效率和灵活性，已经不能满足需求；为了解决这个问题，一种并行可编程的网络处理器被应用到路由器的设计中来。以IXP1200为例，介绍了其体系结构，分析了DifsServ机制原理，对基于网络处理器的：DiffServ体系中边界路由器设计进行了研究，并给出了其实现方法。     

支持IP QOS的新技术--MPLS

多协议标记交换(MPLS)是实现宽带Internet的一种IP与ATM相结合的新兴网络技术。介绍了MPLS的网络构成、基本术语、工作过程,并通过将其与IntServ、DiffServ比较,描述了MPLS对于QoS的支持。     

基于IP DSLAM服务质量转发决策的研究

文章在分析目前网络服务质量(QoS)结构研究状况的基础上,提出了一种基于因特网协议数字用户线接入复用器(IPDSLAM)系统的可实现优先级别业务转发的QoS体系架构和转发决策的解决方案,并详细描述了该体系中的两大核心转发决策的应用原理。     

下一代网络的关键技术IP QoS

随着Internet的飞速发展,对那些有带宽、时延和时延抖动等特殊要求的应用来说,传统互联网所提供的“尽力而为”服务显然不能满足这些要求。因此,在下一代网络中如何提供服务质量(QoS)支持已成为业界研究的热点。目前,因特网工程任务组(IETF)提出了几种满足QoS的服务模型(包括集成服务(IntServ)模型、差分服务(DiffServ)模型和多协议标记交换(MPLS)等)。文中简要介绍了IP QoS的基本概念,详细介绍了这几种模型的原理及其优缺点,最后进一步讨论了IP QoS的发展趋势。     

Scalable Quasi‐Dynamic‐Provisioning‐Based Admission Control Mechanism in Differentiated Service Networks

The architecture in a differentiated services (DiffServ) network is based on a simple model that applies a per‐class service in the core node of the network. However, because the network behavior is simple, the network structure and provisioning is complicated. If a service provider wants dynamic provisioning or a better bandwidth guarantee, the differentiated services network must use a signaling protocol with QoS parameters or an admission control method. Unfortunately, these methods increase the complexity. To overcome the problems with complexity, we investigated scalable dynamic provisioning for admission control in DiffServ networks. We propose a new scalable qDPM² mechanism based on a centralized bandwidth broker and distributed measurement‐based admission control and movable boundary bandwidth management to support heterogeneous QoS requirements in DiffServ networks.     

移动MPLS及其关键技术

移动MPLS将MPLS技术和移动IP技术结合起来，在MPLS网中支持IP的移动性。介绍了移动MPLS的原理，详细阐述了移动MPLS的几种关犍技术：快速切换技术、“三角路由”问题解决方寨和移动MPLS中QoS的实现，最后探讨了移动MPLS技术今后的研究方向。     

Priority switching scheduler

We define a novel core network router scheduling architecture called priority switching scheduler (PSS), to carry and isolate time constrained and elastic traffic flows from best-effort traffic. To date, one possible solution has been to implement a core DiffServ network with standard fair queuing and scheduling mechanisms as proposed in the well-known “A Differentiated Services Code Point (DSCP) for Capacity-Admitted Traffic” from RFC5865. This architecture is one of the most selected solutions by internet service provider for access networks (e.g., customer-premises equipment) and deployed within several performance-enhancing proxies (PEPs) over satellite communications (SATCOM) architectures. In this study, we argue that the proposed standard implementation does not allow to efficiently quantify the reserved capacity for the AF class. By using a novel credit-based shaper mechanism called burst limiting shaper (BLS) to manage the AF class, we show that PSS can provide the same isolation for the time constrained EF class while better quantifying the part allocated to the AF class. PSS operates both when the output link capacity is fixed (e.g., wire links and terrestrial networks) or might vary due to system impairments or weather condition (e.g., wireless or satellite links). We demonstrate the capability of PSS through an emulated SATCOM scenario with variable capacity and show the AF output rate is less dependent on the EF traffic, which improves the quantification of the reserved capacity of AF, without impacting EF traffic.     

IPv6下基于DiffServ机制的煤矿井下网络视频监控模型及其仿真研究

新一代网络协议IPv6协议解决了IPv4在使用过程中出现的IP地址不足的问题,同时提供了IPv4所不支持的QoS机制.针对目前研究较为广泛的DiffServ机制,建立了在极端恶劣的环境--煤矿井下的网络视频监控在DiffServ机制下的模型,并通过仿真以及对仿真结果的分析,指出了该模型在不同的队列排队机制下对网络性能及QoS的影响,为后续对DiffServ机制的研究提出了几点建议.     

Summary of OFC '89, conference on optical fiber communication,February 6–9, 1989, Houston,Texas

The sensitivity of a fiber-optic strain gauge that makes use of interference between the orthogonal linearly polarized eigen-modes propagated in a length of highly birefringent single-mode fiber is primarily determined by tension-induced modal birefiringence ΔB. This ΔB is in a close relationship with the ellipticity of the jacket surrounding the core, on which anisotropic residual stresses are imposed, but ΔB does not depend definitely on the beat length of fiber. Dependence of AB on Young's modulus and the Poisson ratio are computed and discussed in association with the measured results.     

DiffServ网络中一种改进的round robin公平加权调度算法

文中提出了DiffServ网络中一种改进的公平加权round robin调度算法。该算法在网络发生拥塞时,根据各优先业务 类的不同服务等级,动态地改变各优先业务类的调度权重,并同时保持了各优先业务类的相对公平性。通过仿真显 示,该算法在适度满足尽力服务类的同时,能有效处理不同业务类的突发数据,比较迅速地缓解网络的拥塞状况。