EPON系统中的组播技术

文章首先讨论了在以太网无源光网络(EPON)系统上实现组播的现实意义,然后在对现有的二层组播协议分析与比较的基础上,提出采用IGMP Snooping(英特网组管理协议侦听)在EPON上实现组播,并结合EPON自身的特点,提出了实现方案,最后详细描述了光线路终端(OLT)和光网络单元(ONU)是如何支持IP组播业务的.     

A novel dynamic survivable routing in WDM optical networks with/without sparse wavelength conversion

In this paper, we study the dynamic survivable routing problem, both in optical networks without wavelength conversion and in optical networks with sparse wavelength conversion, and propose a novel hybrid algorithm for it based on the combination of mobile agents technique and genetic algorithms (GA). By keeping a suitable number of mobile agents in the network to cooperatively explore the network states and continuously report cycles (that are formed by two disjoint-link routes) into the routing tables, our new hybrid algorithm can promptly determine the first population of cycles for a new request based on the routing table of its source node, without the time consuming process associated with current GA-based lightpath protection schemes. We further improve the performance of our algorithm by introducing a more advanced fitness function that is suitable for both the above networks. Extensive simulation studies on the ns-2 network simulator show that our hybrid algorithm achieves a significantly lower blocking probability than the conventional survivable routing algorithms for all the cases we studied.     

降低射频电路串扰噪声的布线方法

研究并解决了无障碍多层无网格射频电路的布线问题,主要包括三个部分:设计规则、串扰噪声限制和布线方法.首先通过设计规则计算连线参数,运用RLc模型估算串扰噪声,然后,按照需要连接的实节点个数进行归类并提出相应的布线算法.实验结果表明,该布线方法可有效地降低射频电路的串扰噪声.     

Bandwidth‐guaranteed QoS routing of multiple parallel paths in CDMA/TDMA ad hoc wireless networks

This paper investigates the issues of QoS routing in CDMA/TDMA ad hoc networks. Since the available bandwidth is very limited in ad hoc networks, a QoS request between two nodes will be blocked if there does not exist a path that can meet the QoS requirements, even though there is enough free bandwidth in the whole system. In this paper, we propose a new scheme of using multiple paths between two nodes as the route for a QoS call. The aggregate bandwidth of the multiple paths can meet the bandwidth requirement of the call and the delays of these paths are within the required bound of the call. We also propose three strategies by which to choose a set of paths as the route, namely, shortest path first (SPF), largest bandwidth first (LBF), and largest hop‐bandwidth first (LHBF). Extensive simulations have been conducted to evaluate the performance of the three strategies in comparison with a traditional single path routing algorithm. The simulation results show that the proposed multiple paths routing scheme significantly reduces the system blocking rates in various network environments, especially when the network load is heavy. Copyright © 2005 John Wiley & Sons, Ltd.     

一种分布式的洋葱路由新机制

洋葱路由技术在公网上提供双向、实时的匿名通信，其面向连接和严格的源路由方式导致效率低、扩展性差。利用分布式的概念，采用分段连接技术思想提出了一种安全、高效的分布式洋葱路由机制(DORS)，给出了DORS路由实现算法，并从方案实现效率、安全性方面对DORS进行了分析。分析结果表明DORS具有良好的扩展性、鲁棒性、简单性和有效性。     

基于关键节点和多播节点的多播路由算法

在视频会议等多播应用中，降低多播树网络费用非常重要。本文提出了基于关键节点和目的节点的多播路由KDDMC算法。由于在算法中优先考虑采用关键节点，实现更多链路的共享，从而降低网络费用。在随机网络上的仿真结果表明，KDDMC算法的多播树网络费用优于SPH算法。同时证明了KDDMC算法的复杂度为O(n^3)，且利用所提出的路由表算法易于分布式实现。     

多粒度全光网中的多层联合路由

多粒度交换技术利用波带级路由以及光纤级路由,可有效降低光交叉连接器的复杂度.但多粒度交换增加了光网络的逻辑层次结构,使得网络中的路由与资源分配问题更为复杂,因此,在多粒度全光网中实现多层联合路由是提高网络性能的关键.本文对多粒度交叉连接结构进行了分析,并对多粒度全光网中的多层联合路由问题进行了研究.     

三峡-葛洲坝梯级枢纽常规水库调度系统

三峡—葛洲坝梯级枢纽常规水库调度系统是《长江三峡水利枢纽梯级水库调度自动化系统》的高级应用部分,该系统建立在三峡梯级水利枢纽水库调度自动化系统水调数据平台之上,在洪水预报成果的基础上,根据三峡—葛洲坝梯级枢纽的防洪、发电、航运的综合利用要求,作出三峡、葛洲坝电厂长、中、短期出力预报,相应作出梯级枢纽水库调度计划,确定梯级水库的蓄泄对策及闸门的开启计划,制定闸门的操作命令,完整地实现了三峡—葛洲坝梯级枢纽常规水库调度业务。     

传感器网络中基于二元簇的节能路由算法

传感器网络中的分簇算法已经被证明能够有效地节约能量。据此提出了一种基于二元簇的路由算法,其基本思想是网络中的每个节点同时属于2个不同簇,利用二元性来减少在路由发现中的资源浪费,并能够更加确定地发现路由以节约资源。理论分析和模拟实验都表明,该算法在能量消耗和网络生命周期延长方面较优。     

A Bluetooth Routing Protocol Using Evolving Fuzzy Neural Networks

In this paper, a routing protocol which utilizes the characteristics of Bluetooth technology is proposed for Bluetooth-based mobile ad hoc networks. The routing tables are maintained in the master devices and the routing zone radius for each table is adjusted dynamically by using evolving fuzzy neural networks. Observing there exists some useless routing packets which are helpless to build the routing path and increase the network loads in the existing ad hoc routing protocols, we selectively use multiple unicasts or one broadcast when the destination device is out of the routing zone radius coverage of the routing table. The simulation results show that the dynamic adjustment of the routing table size in each master device results in much less reply time of routing request, fewer request packets and useless packets compared with two representative protocols, Zone Routing Protocol and Dynamic Source Routing.