支持QoS的覆盖组播分布式动态路由研究

研究了带度和延时约束的覆盖组播动态路由问题，提出了动态适应性覆盖组播路由协议OMP，给出了一个基于分布式触发重组的组播路由算法——动态覆盖组播路由算法(DDCOMR)，最后对该算法的复杂度进行了推证，对协议和算法的有效性进行了网络模拟。     

支持时延-带宽约束的动态层次组播路由

层次网络及层次路由成为解决大规模网络QoS路由可扩展性问题的一个主要手段.文中对PNNI层次网络模型下的时延-带宽多QoS约束的动态组播路由问题进行了全面研究:在已提出支持时延-带宽约束的拓扑聚集算法(Stair)的基础上,进一步对组播树节点需维护的组播树状态信息及其聚集问题进行研究,并提出"伪树上边界节点"模式的域内组播树状态信息的聚集方法,最后设计了基于聚集拓扑信息和组播树状态信息的动态层次组播路由算法.仿真结果显示,该路由不仅大量压缩了存储和扩散的拓扑信息和组播树状态信息,同时还保持了与平面网络近似的路由效率,实现了大规模网络情况下组播路由的扩展.     

基于委托转发技术的延迟容忍网络组播路由算法*

针对延迟容忍网络中的组播路由问题,提出了一种基于委托转发技术的组播路由算法。该算法是在详细分析组播路由设计需求的基础上,结合延迟容忍网络中节点移动特性,对委托转发技术中节点属性值和节点对转发标准进行重新设计。其节点属性值是面向组播会话的,节点对转发标准是动态适应网络状态的。仿真结果表明,相比于其他基于复制方式的组播路由算法,该算法具有更好的性能,尤其是在对网络开销的控制方面,因此,更适用于延迟容忍网络。     

组播OVERLAY网络动态分布式路由算法

给出了组播覆盖网络MON动态路由的定义,并在此基础上提出了MON动态组播路由计算所应考虑的问题,给出了基于Prüfer编码的覆盖组播树核的生成算法及基于分布式触发重组的MON动态组播路由算法NPPR-N,该文最后对算法的复杂度进行了推证,对算法的有效性进行了以EAD模型为基础平台的网络模拟。     

异构带宽约束的动态层次组播路由

针对动态组播路由中异构带宽约束的问题,提出了可扩展的异构带宽约束的动态层次组播路由框架（Heterogeneous Bandwidth-constrained dynamic Hierarchical Multicast Routing,HBHMR）.为了增添对组成员异质性的支持,HBHMR在支持QoS的层次组播路由算法QHMR（QoS-based HMR）的基础上,增加了对组播树上节点的最大可接收能力信息的收集及其聚集方法的定义,并设计了适用于层次网络的支持组成员动态性和异质性的组播路由算法.理论分析和实验结果表明,HBHMR不仅解决了异构带宽约束的动态组播路由的可扩展性问题,而且具有和基于平面详细网络状态的路由相比拟的带宽阻塞率和组播树的带宽资源占用率.     

组播Overlay网络分布式动态路由的研究

给出了组播覆盖网络MON动态路由的定义,并在此基础上提出了MON动态组播路由计算所应考虑的问题,给出了基于分布式触发重组的MON动态组播路由算法PRRH—N和PRRH—D,最后对算法的复杂度进行了推证,对算法的有效性进行了以EAD模型为基础平台的网络模拟。     

AntNet算法在Ad Hoc网络QoS组播路由中的研究

由于网络拓扑结构变化频繁和节点能量有限的原因, Ad Hoc网络中的QoS组播路由算法必须能够尽快地感知网络中路径的能量状态并且自适应地改变组播路由。 AntNet 算法中的蚂蚁代理能够感知网络中各个子路径的能量状态和更新信息素,从而使组播路由能够衡量整个网络的能量变化情况,最后就找到了考虑到路径能量状态的QoS组播路由。仿真实验表明,该算法能够均衡节点能量从而提高网络性能。     

集中式网络编码组播路由算法

从提高组播容量和降低组播延迟入手,提出了一种集中式网络编码循环增广组播路由算法(centralized network coding cycle augmented multicast routing algorithm,NCCA),从而进一步提高了组播通信的传输速率。首先各节点通过广度优先搜索(breadth first search,BFS)算法遍历链路状态分组获得整个网络的拓扑信息,以Dijkstra算法为基础增广每个信宿节点的路由集,然后选出最优路由集,最后将所有信宿节点的路由集进行组合,得到组播组的整体路由。通过对算法进行理论分析及仿真实验,证明了NCCA组播路由算法在较稳定的网络上能进一步提高组播通信的传输速率。     

计算机通信中的一个组播路由算法

在计算机通信的实际应用中,组播（multicasting）技术日益重要,但由于网络节点处理信息的能力不同,有些节点并不具备组播能力,为此该文用节点的度约束来表示每个节点所具备的组播能力,研究在网络节点具有不同组播能力的路由问题,提出了一种新的解决此问题的利用局部信息的组播路由算法。     

一种减轻组播网络节点负载的贪婪策略

组播网络的路由机制是网络资源优化技术的一个主要研究领域,对路由节点负载能力有严格的要求。保证低负载组播成功的关键在于高效地减轻路由节点负载,研究最小化路由节点转发信息量的算法。基于多点传输机制,兼顾组播组的个数和各组播组中接收者的数量两个影响组播负载的重要因素,运用分布式计算和贪婪策略的思想,提出了一种可以使组播组中路由节点存放的转发信息量的最大值得到最小化,从而减轻组播路由节点负担的策略。通过算法分析和实验仿真说明了所提策略的有效性     

Analysis of bandwidth efficiency in overlay multicasting

Overlay multicasting has been proposed for implementing multicast routing in the application layer as a practical alternative to IP multicasting. Since a packet in overlay multicasting is transmitted via unicast routing between the end hosts, the same packet can be sent over a link multiple times, and thus the main challenge in overlay multicasting is organizing the multicast delivery trees to minimize bandwidth consumption. In this paper, we present a formal analysis of the bandwidth efficiency of overlay multicasting using a simple tree construction algorithm called BestRelay. Our analytical result shows that the bandwidth consumption of overlay multicast routing can be bounded by twice that of optimal IP multicasting. This result is confirmed using simulations.     

基于有限范围组播的Chord路由算法

Chord是一种比较成功的P2P路由算法,但逻辑路径和物理路径之间的不一致性使得单纯依据逻辑距离进行节点路由导致很大的网络延迟,严重影响了路由效率。本文提出了一种基于有限范围组播的Chord路由算法,利用网络层组播技术来获得物理邻居节点,对Chord路由算法进行了改进,大幅度地缩短网络路由查找延时,有效减少了路由跳数,提高了路由性能。     

服务覆盖网络中一种动态流量工程模型与算法

针对服务覆盖网络中的自私路由造成的网络流量失衡将严重影响网络效率和稳定性的问题, 研究如何在覆 盖层应用动态流量工程的方法进行流量优化分配. 基于随机动态优化配流理论, 提出一种服务覆盖网络的动态流量 工程模型, 并设计了分布式的流量工程算法. 该算法可以折衷控制路由的自私与负载均衡的程度. 模拟实验显示, 所 提出的方法较其他方法具有更好的性能, 尤其对于实时动态流量有着较好的适应性.

     

全光网络中组播路由波长分配的一种遗传算法

在WDM网络中，组播是一种重要的通信需求。组播算法就是要建立一棵从源节点到目的节点的组播树，并给这棵组播树分配波长。但是在网络中有波长转换器的情况下计算的复杂性会大大增加。该文在分层图结构中基础上，提出了组播路由和波长分配的一种遗传算法，可以在满足时延约束的情况下，寻找费用最小的组播树，将路由和波长分配统一进行，同时考虑到了网络中波长转换器的存在。数值仿真实验结果表明该算法具有较好的平均性能和较低的时间复杂度。     

一种动态网格Overlay Network拓扑优化蚁群算法

如何提供丰富的通信交互是高级网格应用的关键问题，但是目前的网格技术还不能满足这一需求，提出了一种基于Overlay Network的网格架构来弥补这一不足，如何优化Overlay Network拓扑结构是该架构必须首先解决的重要问题，给出了一种动态环境中拉各朗日蚁群优化算法DLagrAnt，计算的结果显示该算法具有更快的适应性和更小的开销。     

Laurel:一种混合式数据分发覆盖网

覆盖网是各种数据分发应用的基础架构.在节点波动的网络环境中实现快速而准确的数据分发,对覆盖网提出了两个要求:高效的数据路由;较强的系统鲁棒性.已有的覆盖网构建方法多侧重于某个方面的优化,因而未能充分权衡数据路由效率与系统鲁棒性.提出了一种混合式数据分发覆盖网--Laurel.Laurel通过簇间多重结构化拓扑与簇内非结...     

A knowledge-based inference multicast protocol using adaptive fuzzy Petri nets

Multicast routing protocols need a new path discovery algorithm for a newly joining node (receiver) in an ad hoc network. One issue of the approach to find the nearest forwarding node for a new node is that it may increase the distance between the source node and the new members, which results in an increase in latency time and packet loss, as compared with the shortest path algorithms. This issue is important in a high collision network. In this paper, we propose a knowledge-based inference approach for a new path discovery for multicasting. A fuzzy Petri net agent, which is a special expert system, is introduced at each node to learn and to adjust itself to fit the dynamic conditions in a multicast ad hoc network. The simulation results show that the proposed approach is up to 67.17% more efficient in the packet delivery ratio as compared with a bandwidth effective multicast routing protocol.     

Management,control, and design of integrated networks with real-time dynamic routing

Integrated real-time dynamic routing (IRR) networks provide dynamic routing features for multiple classes-of-service on an integrated transport network. In this paper it is shown that IRR networks allow reduced network management costs since with real-time dynamic routing a number of network operations are simplified or eliminated. These simplifications include eliminating the storage of voluminous routing tables in the network switches, eliminating the calculation of routing tables in network design, simplifying the routing administration operations which require downloading new routing information to the network, and eliminating the automatic rerouting function in on-line traffic management. A new bandwidth allocation technique is described here which is based on the optimal solution of a network bandwidth allocation model for IRR networks. The model achieves significant improvement in both the average network blocking and node pair blocking distribution when the network is in a congested state such as under peak-day loads. In a paper to appear in the next Journal issue we further describe a new algorithm for the transport design of IRR networks which achieves near-optimal capacity engineering. These optimization techniques attain significant capital cost reductions and network performance improvements by properly modeling the more efficient operation of IRR networks.     

Ant-based survivable routing in dynamic WDM networks with shared backup paths

In this paper, we consider the problem of survivable routing in dynamic WDM networks with single link failure model. Our work mainly concerns in how to dynamically determine a protection cycle (i.e., two link-disjoint paths between a node pair) to establish a dependable lightpath with backup paths sharing. This problem is identified as NP-complete, thus a heuristic for finding near optimal solution with reasonable computation time is usually preferred. Inspired from the principle of ant colony optimization, we propose in this paper an ant-based mobile agents algorithm for this problem with improved blocking performance. To enable the new ant-based algorithm, we propose to use on each network node both a routing table that contains a set of feasible protection cycles between source destination nodes and also a pheromone table for mobile agents. By keeping a suitable number of mobile agents in a network to continually and proactively update the routing tables based on the current network congestion state, the routing solution of a connection request can be obtained with a reasonable computation time. Extensive simulation results upon the ns-2 network simulator and two typical network topologies show that our new algorithm can achieve a significantly lower blocking probability than the promising algorithm for dynamic lightpath protection proposed in [11] with a comparable computation complexity.