MQ: an integrated mechanism for multimedia multicasting

This paper studies the integration of multimedia multicasting, with the consideration of multicast with end-to-end QoS guarantees by resource reservation, dynamic join and departure of participants, user heterogeneity, scalability, robustness, and loop-free control. A protocol called MQ, Multicast with QoS, is proposed to support multimedia group communications with QoS guarantees for heterogeneous recipients. With MQ, while resource reservation is de-coupled from QoS multicast routing, they are integrated in a way to avoid the problem of “sender-oriented” path determination, a problem that occurs when RSVP is used in conjunction with QoS routing for heterogeneous reservations. Being a truly receiver-oriented and integrated scheme for multimedia multicasting, MQ supports such integration in a robust, scalable and loop-free way. It also accommodates heterogeneous users with varied QoS, dynamically adjusts QoS trees to improve resource utilization, and guarantees end-to-end QoS requirements. We have conducted simulations to evaluate the performance of the proposed mechanism. MQ demonstrates its advantages over the conventional loosely coupled integration of TP multicasting, resource reservation and QoS routing, in terms of better accommodation of heterogeneous users, higher scalability, lower blocking probability for users to join groups with service guarantees, and more efficient resource utilization to enhance system performance     

基于RSVP实时应用的QoS性能研究

介绍了当前网络服务质量的热点之一———RSVP协议。利用OPNET模拟日常业务流对实时应用所造成的影响,并就RSVP在实时系统中的应用进行了仿真和QoS性能评估,结果证明RSVP能够很好地为实时应用提供端到端的资源预留,并使带宽、延迟、丢包率、抖动等QoS参数得到明显改善。文中所列参数对将来在实际网络中的部署具有指导意义。     

适用于移动MPLS的改进RSVP协议研究

首先提出了一种改进的资源预留协议,能够保证基于分级移动的移动MPLS在切换过程中连续的集中服务质量。阐述了该改进协议的工作过程,证明了它能很好地适应移动MPLS,并能保证对移动MPLS在切换后的新路径进行快速的资源预留,从而保障业务的集中服务质量。最后,给出仿真结果并进行分析。     

RSVP协议在移动IPv6网络中的扩展性研究

针对无线移动通信的特点,提出了一种在移动IPv6网络中保障用户通信服务质量的资源预留新方案Fast RSVP.该方案采用跨层设计的思想,将两个不同层次的模块:移动IPv6模块和RSVP模块结合起来,通过在两个模块之间增加一些原语使得二者配合工作以保证移动用户的通信业务质量.Fast RSVP方案引入了邻居隧道提前资源预留、优化路径资源预留、切换预留、路径融合等一系列新机制.仿真实验结果表明,与其他移动环境中的RSVP扩展方案相比,该Fast RSVP方案在支持无线移动通信方面具有如下优势:(1)能够实现移动节点带有服务质量保证的快速切换;(2)能够避免移动IP切换过程中三角路由和重复预留造成的资源浪费;(3)能够区分不同类型的切换预留请求,在保证网络整体性能的前提下显著降低因为切换而导致的服务中断率.     

基于RSVP协议的QoS分级过滤机制研究

为满足不同等级的端到端QoS要求,本文提出了一种基于RSVP协议的QoS分级过滤机制。该机制对同一会话中的数据进行分级,并通过扩展RSVP信令,定义相应的服务等级,使 得路由结点可通过QoS过滤机制过滤摔高于预约服务等级的数据包。经模拟验证,该机制在带宽资源不足的网络环境中,能有效缓解网络拥塞,更好地保证端到端的QoS。     

层次化移动IPv6环境中的QoS机制

本文针对层次化移动IPv6的网络提出了一种QoS信令，为移动节点提供服务质量的保障。在分析了RSVP信令的特点及其由于对多播的支持而增加的复杂性的基础上，设计了一个简化的RSVP信令，然后把此RSVP信令和层次化的移动协议相结合提出了一个综合的QoS切换方案，并在层次化的移动环境下，对此QoS信令和其它几种QoS机制在资源预留时间和信令负荷方面进行了性能比较。     

基于集成服务的IP网络QoS实现技术

讨论了基于集成服务的IP网络中为实时业务预留资源的方法 ,利用RTP/RTCP实现实时业务传输的有效控制机制 ,以及利用IP数据分组头中的优先级及IPv6头中的流标记信息 ,为实时业务获得优先服务和快速转发的方法 ,实现实时业务在IP网络中传输的QoS。     

全IP移动网络中的动态资源预留机制与QoS研究

全IP移动网络中的QoS是最近的研究热点之一,其中资源预留协议(Resource ReserVation Protocol,RSVP)是一个关键技术。为了保证切换时的QoS,需要进行资源预留。针对RSVP不适应移动环境的缺点,文中在全IP移动网络的接入网的微移动域中,提出一种动态资源预留的QoS解决方案,实现微移动协议和RSVP协议之间的互操作。当有多个移动主机需要进行预留时,需要对它们进行优先级排序。文中提出了一种在全IP移动网络中基于信令预测优先级排队的动态排序算法,以有效地对多个移动主机进行资源预留。仿真结果表明文中提出的算法的有效性。     

基于Linux平台的NSIS协议试验床搭建与端到端QoS保障机制研究

在网络通信中,服务质量QoS（Quality of Service）是衡量一个网络可靠性、稳定性的重要指标。本文阐述了服务质量QoS的性能指标、模型框架,并从QoS保障控制层面的资源预留角度介绍了资源预留常用的RSVP（Resource ReSerVation Protocol）与NSIS（Next Steps In Singnaling）协议,然后介绍了Linux环境下基于NSIS协议的试验床搭建过程,最后在试验床的基础上实现了端到端的资源预留并进行了验证。     

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。     

基于HMIPv6的RSVP新方案

在移动IPv6环境中,IntServ/RSVP模型很难实现QoS保证。针对该问题提出一种新的资源预留方案,该方案建立在分层移动IPv6协议的基础上。分析移动节点在域内的资源预留机制,与MRSVP, HMRSVP进行性能比较,结果表明该方案具有较高性能。     

一种基于移动代理的RSVP实现方案

文中提出了一种基于移动代理的资源预留实现方案，引入探路代理和隧道代理两种移动代理．通过SNMP代理访问MIB收集隧道中路由器的资源信息，消除了隧道的不确定性，有效地提高了RSVP的实用性。     

Performance evaluation framework for IP resource reservation signalling

This paper investigates the scalability limitations of signalling-based Quality of Service (QoS) provisioning using the RSVP and Boomerang protocols as examples. We establish a performance evaluation framework, which contains per hop metrics for describing the router’s signalling capability and per reservation metrics for characterising the overall performance of the reservation protocol. The per hop metrics are captured in a simple router model, using parameters that are based on actual measurements. This router model is used in a simulation scenario, which characterises the end-to-end impact and overall performance of the RSVP and Boomerang reservation protocols.

This paper summarises the results of router benchmarking measurements and simulations. The per session results highlight that, with thorough selection of the control protocol, signalling-based resource reservation is a realistic approach in the Internet. It is also shown that the selection of the signalling protocol can seriously influence the reservation performance of a router and thus the overall performance of the entire network as well. The presented performance evaluation framework can be used for network dimensioning and it can even aid the design of new resource reservation protocols and new router devices.     

移动Ad hoc网络与Internet互连的QoS保障机制

通过对IntServ／RSVP模型、DiffServ模型、基于IntServ网络的MRSVP的分析和比较,提出了一种新的MANET移动接入QoS保障框架,并在MANET移动接入方法和层次化算法的基础上提出了一种新的资源预留协议MMRSVP。该协议与MRSVP和RSVP相比,实现简单、操作方便,能很好地节省网络资源。     

Dynamic multi-resource advance reservation in grid environment

How to guarantee user’s QoS (Quality of Service) demands become increasingly important in a service-oriented grid environment. Current research on grid resource advance reservation, a well known and effective mechanism to guarantee QoS, fails to adapt to dynamic behavior of grid, and cannot solve imprecise deny of reservation request problem efficiently. For this, enabling system architecture for advance reservation is proposed. Virtual resource container (VRC) is adopted to alleviate a negative effect resulted from dynamic behavior of grid and QoS deviation distance (QDD) based logical resource selection algorithm is put forward to decrease imprecise reject ratio of reservation. At last, this new architecture is deployed to campus grid, and two illustrative experiments are conducted. Experimental results show that system architecture for advance reservation proposed in this paper can alleviate negative influence of grid resource dynamic fluctuation and avoid imprecise reject of advance reservation request effectively.     

Dynamic rerouting of guaranteed Quality-of-Service connections

To support the widespread demands for integrated services various solutions have been proposed to provide guaranteed Quality-of-Service (QoS) services in packetswitched networks. These solutions usually require fixed route selection and resource reservation on a per connection basis. The routing and reservation decisions, combined with load fluctuations, introduce the problems of network unavailability and loss of network management flexibility. We believe that these problems can be alleviated by transparently rerouting connections to properly balance the network load. In this paper, we present a solution that supportstransparent route modification ofguaranteed QoS connections during the life time of the connections. As the emphasis of this work is to support transparency we must ensure that during and after the rerouting, the QoS guarantees made to the client are preserved, and the interface instances at both the sender and receiver are unaltered. Our solution includes the mechanisms that support the transparent rerouting of connections, and a routing algorithm that is based on the traffic characteristics, the delay, and the jitter requirements of a connection. This routing algorithm can also use various administrative constraints and facilitate the reuse of resources currently reserved by the connection. To optimize the solution, additional mechanisms have been introduced to reduce the time needed to reroute a connection and to support rerouting of segments of a connection. The solution has been implemented in the context of the Tenet scheme and route changes can be observed and controlled by using the Simple Network Management Protocol (SNMPv 1). Simulation experiments and some initial measurements of the implementation demonstrate that such a scheme is useful, practical, and can be achieved with load overhead.     

Resource Management Middleware for Dynamic,Dependable Real-Time Systems

Thispaper presents resource management techniques that achieve thequality of service (QoS) requirements of dynamic real-time systemsusing open architectures and commercial off-the-shelf technologies(COTS). Dynamic real-time systems are subject to constant changessuch as a varying external environment, overload of internalsystems, component failure, and evolving operational requirements.Examples of such systems include the emerging generation of computer-based,command and control systems of the U.S. Navy. To enable the engineeringof such systems, we present adaptive resource management middlewaretechniques that achieve the QoS requirements of the system. Themiddleware performs QoS monitoring and failure detection, QoSdiagnosis, and reallocation of resources to adapt the systemto achieve acceptable levels of QoS. Experimental characterizationsof the middleware using a real-time benchmark illustrate itseffectiveness for adapting the system for achieving the desiredreal-time and survivability QoS during overload situations.     

利用RSVP隧道高效实现INTERNET的服务质量请求

在ＩＮＴＥＲＮＥＴ上应用ＲＳＶＰ时,新增通信量和时空开销问题是ＲＳＶＰ研究的关键问题之一。文中提出了利用ＲＳＶＰ隧道和ＱｏＳ请求聚合体解决此问题的方案,核心内容是：ＱｏＳ请求聚合体代表多个具有指定特征的ＲＳＶＰ会话消息,隧道段的路由器的ＲＳＶＰ模块对聚合体会话消息设置软状态而不理会构成聚合体的单个会话消息、构成聚合体的每个一ＲＳＶＰ会话消息被封装后以普通数据包形式通过隧道段。     

HeiRAT - Quality-of-service management for distributed multimedia systems

Multimedia systems must be able to support a certain quality of service (QoS) to satisfy the stringent real-time performance requirements of their applications. HeiRAT, the Heidelberg Resource Administration Technique, is a comprehensive QoS management system that was designed and implemented in connection with a distributed multimedia platform for networked PCs and workstations. HeiRAT includes techniques for QoS negotiation, QoS calculation, resource reservation, and resource scheduling for local and network resources.     

一个自适应的支持资源预定的路由算法

新型的应用问题，如视屏会议、分布式模拟等需要保障质量，资源豫剧 定协议如ＲＳＶＰ等可以用来提供有保障的服务质量，介它需要有新的路由协议。为此，文中提供一种自适应的、支持资源预定的、多点通讯的路由算法，并描述了该算法的特性。