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This paper reports on a novel strategy and related algorithm for realizing dynamic routing and grooming into wavelengths of data flows (label switched paths, LSPs) in new generation optical networks based on generalized MPLS (GMPLS). The method allows arbitrary granularities of LSPs. The new generation network is modeled as a multi-layer network consisting of an IP/MPLS layer and an optical layer. In particular, the proposed solution adopts a dynamic routing algorithm based on the Dijkstra algorithm, that makes use of a weight system, integrated with a suitable method for grooming LSPs into wavelengths based on the packing criterion, thus harmonizing the features of MPLS packet flows whose bandwidth vary in a continuous range of values, with the optical world, where the wavelength bandwidth ranges according to discrete values. The weight system is based on the concepts of least resistance routing that allows to evenly distribute the traffic at the MPLS layer, while packing improves the use of optical resources by favoring more filled wavelengths with respect to the emptier ones. To assess the validity of the proposed solution a simulation model has been realized. The results obtained by simulation show that the packing criterion allows reducing the refused bandwidth from two down to about four times, for a network load of 70% and 55%, respectively, when compared with the alternative method named spreading. The dependence of the proposed solution on bandwidth granularity has been also investigated. Moreover, in order to demonstrate the superior performance of the proposed routing solution, a comparison between the proposed strategy with relevant solutions known in the literature, based on either a single or multi-layer approach, is also reported. In order to perform the comparison, all the reference routing solutions that have been considered adopt the packing method for LSP grooming into the lightpaths. The results show that our solution outperforms the others in terms of amount of traffic that can be on-line accommodated. For instance, assuming a blocking probability of 10–3, the proposed solution is able to further reduce the refused bandwidth of the best routing algorithm considered in the analysis by a factor of three times, thanks to the knowledge of optical resource availability. 相似文献
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本文的主要工作是建立基于MPLS的流量工程模型.在商业运行的网络中,通过对已投资设施的充分利用获取竞争优势和商业回报的要求使得流量工程日益成为网络运营中不可缺少的手段.通过借鉴TCP和ATM的优点,结合面向连接和面向非连接两种处理方法的长处,建立一种基于MPLS的流量管理模型,该模型的特点是:管理功能模块边缘化,运输功能模块平面化,在高速,简单的运载核心上运行一个可管理的流量承载平台.模型的有效性通过两个方法得到评估.一是从形式上证明了模型运行状态的稳定性,完备性和对于时间轴的收敛性.二是使用Network Simulator建立模拟的网络环境验证对网络运行状态的优化结果.本文的工作基于以下重要概念:基于聚集的流量、流聚集、流量聚集点和流量分解点、扩充的链路耗费参数定义(承载能力占用率)、分布式公平队列等. 相似文献
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自适应流媒体技术用户体验的好坏,很大程度上由流媒体应用对端到端带宽估计的准确度决定,而在高度动态的LTE网络中,对带宽的估计极具挑战。设计并实现了一种基于LTE资源块感知的自适应无线流媒体系统,系统中的LTE资源块监测模块监测当前蜂窝小区范围内的物理层资源占用情况;速率映射机制据此将视频分片下载速率映射为当前可用带宽;码率自适应算法结合当前LTE网络中潜在可用带宽和当前视频缓存状况,选择最合适的码率版本,以实现视频质量和播放卡顿之间的折中。在原型系统上的测试实验中,与两种基线码率自适应算法进行对比,所提方法在保持极低的播放卡顿率的情况下获得了最高的平均视频码率,有效提升了用户的视频观看体验。 相似文献
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一种实现流量工程的约束路由算法 总被引:2,自引:0,他引:2
提出了一种在动态网络中实现流量工程的分布式约束路由算法。该算法以增强型内部网关路由协议(EIGRP)收集网络资源信息,以优化的泛洪算法来获取显示路由。该算法采用延时和带宽为约束条件,其实现简单,满足动态组网的要求,并避免了传统泛洪机制在寻路过程中造成的网络资源的浪费。最后,给出了算法的实现框架。 相似文献