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1.
音视频传输对网络的带宽、时延和丢包率有较高的要求。但是Internet是一个尽力而为的网络.没有提供任何的服务质量(QoS,Quality of Service)。本文方案基于应用层对QoS加以控制:在发送端控制发送速率;在接受端进行纠错控制以实现连续播放。  相似文献   

2.
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。  相似文献   

3.
移动AdHoc网络(MANET)支持QoS保证的能力,受限于无线介质的带宽和节点的移动特性。由于节点的移动,网络拓朴频繁发生变化,一旦节点移动,当前的路由就很容易失效,从而造成通讯中断,这种情况就是链路失效。QoS路由是MANET获得端到端QoS保证的第1步。然而,拓朴变化造成的链路失效状况的存在,使得路由的可靠性对于QoS路由而言非常重要。为使链路失效造成的影响最小,找到生存时间长并且可靠性高的路由就显得尤为重要。提出了一种在MANET中支持Oos路由,并能较好解决链路失效状况的方案。该方案定义了一种新机制,在执行时类似表驱路由协议,通过利用主路径上被共享的邻居节点信息,为主路径上各个独立的子路径预备了可替换的路径。  相似文献   

4.
马小强  张春业  张波 《计算机工程》2010,36(10):124-126
分析IEEE 802.16的QoS机制,针对其没有详细规定接纳控制算法的情况,结合协议中定义的业务类型QoS特性,在信令交互机制下,提出一种基于优先级的动态带宽分配接纳控制机制。仿真结果表明,与预留带宽的固定带宽分配机制相比,采用该机制后,系统的切换连接掉线率、新增连接的阻塞率和带宽利用率得到改善。  相似文献   

5.
一种新的QoS覆盖多播路由协议的研究   总被引:4,自引:0,他引:4  
研究了QoS覆盖多播路由问题,对度约束模型进行扩展,提出了一个新的支持QoS路南的覆盖多播网络模型.基于此模型,提出丁一个新的QoS覆盖多播路南协议QOS覆盖多播树协议(QOMTP).该协议采用分布式和树优先的策略,使多播组成员之间能自组织地构建一棵基于源的、满足QoS约束的覆盖多播树.该协议采用了一种新的启发式局部优化算法,通过调节启发因子,能灵活地在延时和带宽之间进行均衡.仿真实验表明,采用按请求带宽转发媒体流,并选择适当的启发因子,QOMTP协议能减少多播树上节点的网络资源占用越,同时获得较高的节点接纳率和较好的动态适心性,从而证明了该协议机制及其算法的有效性.  相似文献   

6.
MAODV协议的QoS延伸   总被引:4,自引:0,他引:4  
研讨了Ad Hoc网络中具有QoS约束的多播路由问题和网络模型,提出了一种基于延伸MAODV(Multicast Ad Hoc On-demand Distance Vector)多播路由协议的延时、带宽和包丢失率等度量的QoS多播路由协议。仿真实验显示该协议较好地改进b 端到端传输延时、带宽利用率和传输性能,为Ad Hoc网络QoS多播路由提供了一种新的有效途径。  相似文献   

7.
张中荃  党秋磊  谢国益 《微计算机信息》2007,23(30):241-243,122
接纳控制作为一种预防性的流量控制手段是实现网络服务质量(QoS)保障的重要手段。本文在研究基于测量的接纳控制技术原理的基础上,着重分析了基于探测的接纳控制方法存在的问题,并对其中的“链路带宽重复评测”问题的解决方法进行了改进,提出了基于资源预留标签探测机制并给出了探测流程,最后通过仿真验证了该探测机制的有效性。  相似文献   

8.
为更好地将移动自组网络用于网络控制系统(NCS),结合NCS的网络特性,提出了一种基于链路信号质量的QoS路由算法。主要QoS机制包括根据接收信号强度选择较稳定的路由;用Hello报文广播节点的预留带宽;中间节点为所有受影响的数据流修复路由、目的节点向源节点广播路由修复报文进行路由修复。NS2仿真表明当节点移动性强时,该QoS路由算法可有效减少网络的平均端到端时延和丢包率,提高控制系统稳定性。  相似文献   

9.
HAPS-GEO卫星空间IP网络结构及端到端QoS方案研究   总被引:1,自引:1,他引:0  
研究了基于临空平台和GEO卫星的空间IP网络一体化结构以及端到端的服务质量(QoS)方案。依据临空平台和卫星通信网络的特点,首先设计了临空平台-GEO卫星空间IP网络的基本结构,进一步分析了各中转节点的处理职能、空间链路组成形式和建立过程。在通信业务的划分基础上,分析了传统IP网络的端到端QoS方案—综合服务(IntServ)和区分服务(DiffServ)的优缺点,结合临空平台-GEO卫星空间IP网络结构特点,提出了IntServ/DiffServ分区结合端到端QoS方案。通过OPNET仿真,分析了网络的  相似文献   

10.
为了有效利用网络带宽和能量资源,延长网络生存时间,提出一种用于AdHoc网络基于节点剩余能量和路由传输能量的Qos路由协议(QRETP)。该协议通过计算节点带宽保证路由协议对QoS的要求,同时,综合考虑节点剩余能量和传输能量的状况,一方面以避免网络分割为目标,均衡节点能量耗损;另一方面从网络能量有限的角度出发,节省网络能耗。仿真表明,该协议在网络生存时间、节点平均能量消耗以及分组投递率等方面都有一定程度的改善。  相似文献   

11.
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.  相似文献   

12.
DiffServ网络中接纳控制方法的研究   总被引:1,自引:0,他引:1  
俞承志  宋瀚涛  刘莉 《计算机工程》2005,31(6):95-97,221
深入分析了DiffServ网络中接纳控制方法的缺点,提出了一种新的接纳控制方法.该方法将边界和内部接纳控制分开进行.边界接纳控制时,采用边界区分服务策略,根据流对QoS不同要求,将流分为两类区别对待,不但提高了网络资源利用率,而且保证了流的服务质量;内部接纳挖制时,采用了基于路径的方法,大大提高了网络接纳控制的效率.  相似文献   

13.
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.  相似文献   


14.
Although the Differentiated Services architecture supports scalable packet forwarding based on aggregate flows, the detailed procedure of Quality of Service (QoS) flow set-up within this architecture has not been well established. In this paper we explore the possibility of a scalable QoS flow set-up using a sink-tree paradigm. The paradigm initially constructs a sink tree at each egress edge router using network topology and bandwidth information provided by a QoS extended version of Open Shortest Path First (OSPF), which is a widely used link-state routing protocol. Our sink-tree paradigm dynamically reallocates network bandwidths online according to traffic demands. As a consequence, our paradigm easily supports QoS routing, resource allocation, and admission control at ingress edge routers without consulting core routers in a way that the QoS flow set-up time and overhead are minimized. Simulation results are very encouraging in that the proposed methodology requires significantly less communication overhead in setting up QoS flows compared to the traditional per-flow signaling-based methodology while still maintaining high resource utilization.  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
The issue of resource management in multi-domain Differentiated Services (DiffServ) networks has attracted a lot of attention from researchers who have proposed various provisioning, adaptive marking and admission control schemes. In this paper, we propose a Reinforcement Learning-based Adaptive Marking (RLAM) approach for providing assured end-to-end quality of service (QoS) in the form of end-to-end delay and throughput assurances, while minimizing packet transmission cost since ‘expensive’ Per Hop Behaviors like Expedited Forwarding (EF) are used only when necessary. The proposed scheme tries to satisfy per flow end-to-end QoS through control action,s which act on flow aggregates in the core of the network. Using an ns2 simulation of a multi-domain DiffServ network with multimedia traffic, the RLAM scheme is shown to be effective in significantly lowering packet transmission costs without sacrificing end-to-end QoS, when compared to the commonly used static marking scheme.  相似文献   

18.
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.  相似文献   

19.
分级统筹分配令牌参数的流量整形算法   总被引:1,自引:0,他引:1  
涂文伟  张进  张兴明 《计算机应用》2006,26(9):2175-2177
在区分服务网络中,流量整形是提供QoS保证的一项重要的技术,通常用于规整用户系统向网络提交的数据流。提出了一个新的流量整形架构——分级统筹令牌参数分配(HHTPA)整形器,在边缘路由器上通过分级整形、统筹实时更新令牌桶参数,动态分配剩余带宽,达到对用户数据进行流量整形和提高带宽利用率的目的,使得为高优先级服务预留但未使用的带宽也可被低优先级的服务使用。  相似文献   

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