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弹性分组环作为解决城域网的问题的一个方案被提出后,迅速成为研究的热点,但专用的RPR芯片还未商品化。提出了一种利用不支持RPR协议的网络处理器借助协议转换器来构建RPR模块的设计方案。协议转换器的主要功能是RPR/Ethernet帧转换和接口转换。文章介绍了RPR模块的结构和功能,并讨论了协议转换器的实现。 相似文献
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Resilient packet ring (RPR) standardized as IEEE 802.17 is a new medium access control (MAC) protocol for metro-ring networks. RPR supports spatial reuse which increases the achieved throughput but it can also result in congestion and starvation of nodes on the ring. Therefore, it is necessary to employ mechanisms to enforce a fair allocation of the ring bandwidth in RPR. In order to maintain fairness among nodes, a fairness algorithm is deployed at each RPR node. When a node detects congestion, it calculates a fair rate which is advertised to all upstream nodes contributing to congestion. Upon receiving the fair rate, the upstream nodes limit the rate of their injected traffic to the advertised fair rate. Consequently, the congested node can utilize the unused capacity and add its local traffic to the ring. In this paper, we develop an analytical model for fair rate calculation in the RPR aggressive mode fairness algorithm in the parking-lot scenario. This model provides an insight on dynamics of the RPR fairness algorithm and can be used to evaluate its performance. We investigate this problem in two cases. First, we assume that the link propagation delay is zero and derive the fair rate equations for this ideal case. We then consider the link propagation delay and develop a more realistic model. We verify the accuracy of our model by simulation results. Furthermore, we use the developed model to study the impact of various parameters on convergence of the fair rate. 相似文献
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The resilient packet ring (RPR) is a data optimized ring network, where one of the key issues is on load balancing for competing streams of elastic traffic. This paper suggests three efficient traffic loading algorithms on the RPR. For the algorithms, we evaluate their efficiency via analysis or simulation. 相似文献
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The resilient packet ring (RPR) IEEE 802.17 standards is under development as a new high-speed technology for metropolitan backbone networks. A key performance objective of PRP is to simultaneously achieve high utilization, spatial reuse, and fairness, an objective not achieved by current technologies such as SONET and Gigabit Ethernet or legacy ring technologies, such as FDDI. The core technical challenge for RPR is the design of a fairness algorithm that dynamically throttles traffic to achieve these properties. The difficulty is in the distributed nature of the problem, that upstream ring nodes must inject traffic at a rate according to congestion and fairness criteria downstream. This article provides an overview of the RPR protocol with a focus on medium access and fairness. 相似文献
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随着各电信运营商大力开展宽带域网建设,如何提代电信级的数据服务变得越来越重要。本文详细阐述了新型的弹性分组数据环(RPR)技术的特征,以及RPR技术与SDH、以太网技术相比在环形拓扑结构上支持数据业务的优势。 相似文献
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弹性分组环(RPR)是为优化IP数据包传输提出的新协议,目前正由IEEE802.17工作组进行标准化工作。文章介绍RPR技术及其在城域网中的应用,展望RPR技术的发展前景。 相似文献
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RPR是由顺时针、逆时针两个传输方向光环组成的,这种组网方式赋予RPR的健壮性。RPR的保护倒换机制主要有两种:采用定向保护机制和采用回绕保护机制。首先概述了RPR网络保护协议,然后分析了RPR的保护倒换机制及RPR的网络保护与SDH保护方式的互通。 相似文献
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IEEE802.17弹性分组环是宽带城域网的新型技术。凭着本地公平算法、空间重利用、带宽统计复用、正常状态双环均传输业务等特点从而和传统环网相比,弹性分组环在带宽利用方面具有较大的优势。公平算法对弹性分组环发挥其带宽利用优势具有极其重要的作用,而目前的基于节点公平算法不能完全发挥弹性分组环的优势。文章在更能发挥弹性分组环带宽利用优势的基于流的公平策略的基础上,建立相应的算法方案,并进行计算机仿真验证。实验结果验证了理论分析。 相似文献
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根据IEEE802.17正在进行标准化的弹性分组环协议,分析了RPR中数据通路的结构。同时对数据通路中业务服务质量及保护功能进行了讨论。 相似文献
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弹性分组环(RPR)是一种新的城域网技术。在本文中通过假定一种RPR网络节点结构和对RPR公平性问题的分析,介绍了一种新的经济有效算法:逻辑节点重新排序法,并进行了实例分析。 相似文献
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翟德怀 《电信工程技术与标准化》2004,(9):60-63
在将RPR内嵌入MSTP并应用于城域环网时,公平算法(FA)无疑是最重要的RPR特性之一.本文首先介绍RPR公平算法的基本原理,并在此基础上,进一步分析了公平算法在不同层次城域环网应用中的公平使用带宽特性,及其对空间再利用特性的支持. 相似文献
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弹性分组环中的公平算法浅析 总被引:6,自引:0,他引:6
弹性分组环(RPR,Resilient Packet Ring)作为下一代高速城域网的核心技术,具有高的带宽利用率、空间再利用和公平性等优良的特性。但要动态地获得这些特性,必须设计合理的带宽分配算法。文章指出了目前所采用的公平算法中存在的一些问题,探讨了一种更新的带宽分配算法;分布式虚拟时间调度(DVSR,Distributed Virtual-time Scheduling in Rings)算法。 相似文献
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Maier M. Herzog M. Scheutzow M. Reisslein M. 《Lightwave Technology, Journal of》2005,23(10):2816-2838
The two protection methods wrapping and steering used in IEEE 802.17 resilient packet ring (RPR) provide fast but very inefficient and limited network failure recovery. Due to the increased length of the backup path, RPR suffers from high traffic loss, a decreased throughput-delay performance, and the lack of resilience against multiple link and/or node failures. To achieve an improved resilience, interconnecting a subset of the ring nodes by means of a dark-fiber single-hop star wavelength division multiplexing (WDM) network is proposed. In doing so, the ring network is divided into separate domains, each being fully recoverable from a single link or node failure without losing full network connectivity. A novel hybrid fault recovery technique, termed protectoration, is proposed and examined by means of probabilistic analysis and simulation in terms of stability, channel utilization, and throughput-delay performance. The proposed protectoration technique 1) combines the fast recovery time of protection and the bandwidth efficiency of restoration, 2) provides full recovery from multiple link and node failures, 3) builds on both wrapping and steering protection methods of RPR and, thus, allows for an evolutionary upgrade of existing RPR networks, and 4) does not require the convergence of routing protocols in response to failures and, thus, improves the routing stability and network availability. Numerical investigations in this paper show that the location of failures has a strong impact on the network performance. For a given failure location, the protectoration technique is able to accommodate multiple ring failures without significant performance loss. 相似文献