WDM全光网络中实时组播的分布式路由与波长分配算法

在WDM网络中，由于每条链路上可用波长是动态变化的，在考虑波长转换延迟的条件下，实现实时组播连接的路由与波长分配是十分困难的．假定WDM网络中每条链路有多根光纤，只有部分结点具有波长转换器且波长转换时间是不可忽略的，据此提出了一种用于建立实时组播连接的分布式路由与波长分配算法．该算法以Prim最小生成树算法为基础，生成一棵满足给定延迟时限的最小成本树．当最小成本树不能包括所有目的结点时，对剩余目的结点生成一棵最短延迟树，然后合并两棵树得到一棵组播树．波长分配使用最少波长转换和负载平衡策略．     

WDM网络中满足延迟和延迟差约束的分布式组播路由与波长分配算法

在WDM网络中,由于每条链路上可用波长是动态变化的,在考虑波长转换延迟时间的条件下,实现实时组播连接的路由与波长分配是十分困难的。论文提出了一种用于建立满足延迟时限和延迟差要求的实时组播连接的分布式路由与波长分配算法。该算法假定每个节点没有全局路由信息,只根据关联链路的信息进行路由选择,且将路由与波长分配统一进行。组播路由算法以Prim最小生成树算法为基础,生成一棵满足给定延迟时限的最小成本树。对不满足延迟时限的目的节点,通过增加回路边构造回路再消除长延迟路径的方式,加入到组播树中。对不满足延迟差的目的节点,采用重构Steiner树的方法,使其满足延迟差的要求。波长分配使用最少波长转换和负载平衡策略。     

WDM网络中实时组播的分布式路由与波长分配算法

在WDM网络中,由于每条链路上可用波长是动态变化的,在考虑波长转换延迟时间的条件下,实现实时组播连接的路由与波长分配是十分困难的。该文提出了一种用于建立实时组播连接的分布式路由与波长分配算法。该算法将路由与波长分配统一进行,大大减少连接的建立时间。组播路由算法以Prim最小生成树算法和K-度宽度优先搜索方法为基础,生成一棵满足给定延迟时限的最小成本树。波长分配使用最少波长转换和负载平衡策略。     

WDM网络中实时组播的分布式优化RWA算法

在WDM网络中,由于每条链路上可用波长是动态变化的,在考虑波长转换延迟时间的条件下,实现实时组播连接的路由选择与波长分配是十分困难的。论文提出了一种用于建立实时组播连接的分布式路由选择与波长分配算法。该算法将路由选择与波长分配统一进行,大大减少连接的建立时间。组播路由算法以Prim最小生成树算法为基础,生成一棵满足给定延迟时限的最小成本树。波长分配使用最少波长转换和同一波长最长使用策略。     

IP／DWDM光因特网中一种基于人工免疫算法的QOS组播路由算法

本文提出了一种IP／DWDM光因特网中基于人工免疫算法的QoS组播路由算法，当QoS组播请求和需求区间给定时，能够找到一棵基于QoS的柔性费用近优组播路由树。该算法基于人工免疫算法构造QoS组播路由树，并基于波长图对树进行波长分配，将路由和波长分配集成到一个过程中，同时考虑了负载平衡。仿真结果表明，算法为IP／DWDM光因特网中的组播应用构造的QoS组播路由树是可行和有效的。     

IP/DWDM光Internet中智能QoS组播路由算法

提出了一种IP／DWDM光Internet中基于蚁群算法的智能QoS组播路由算法。给定QoS组播请求与用户延迟需求区间,提出的算法寻找一棵基于柔性QoS的成本近优组播路由树。它基于蚁群算法来构造组播路由树,并基于波长图思想对组播路山树进行波长分配,一体化考虑组播路由选择和波长分配问题,同时还考虑了IP／DWDM光Internet中的负载均衡问题。仿真研究表明,算法是可行和有效的。     

IP/DWDM光因特网中一种混合一体化QoS组播路由算法

研究了IP/DWDM光因特网中一体化QoS组播路由算法,在考虑负载均衡的前提下,针对用户组播请求与柔性QoS需求,寻找一棵QoS组播路由树。由于该问题的NP难属性,因此提出一种基于模拟退火和禁忌搜索的混合算法来构造费用近优QoS组播路由树,同时集成一种基于分段和波长图思想的波长分配算法,一体化解决路由与波长分配问题。仿真结果表明,提出的算法是可行和有效的。     

一种光因特网中的一体化QoS组播路由算法

讨论了IP/DWDM光因特网中的一体化多约束QoS组播路由和波长分配算法。给定一个QoS组播请求,包括带宽需求、组播端到端延迟上界和延迟抖动上界,提出了一种算法,它能够找到一棵同时满足上述三个约束的组播树。提出的算法基于一种类似于波长图的逻辑拓扑来构造组播树。逻辑拓扑上的路径同时指出路由和该路由上的可用波长。通过这种方式,算法将路由和波长分配集成在一起一体化考虑。最后,阐述了算法的正确性。     

基于禁忌搜索的集成式QoS组播路由算法

研究了IP／DWDM光因特网中的集成式QoS组播路由算法,在考虑负载均衡的前提下,针对用户组播请求与柔性QoS需求,寻找一棵QoS组播路由树。由于该问题的NP难属性,因此基于禁忌搜索算法来构造费用近优QoS组播路由树,同时集成一种基于分段和波长图思想的波长分配算法,一体化解决路由与波长分配问题。仿真结果表明,提出的算法是可行和有效的。     

一种公平分配代价的组播路由算法

本文提出了一种公平分配代价的组播路由算法 DFC_ DCMT- -分布式公平分配代价的延迟受限组播路由算法 ,该算法在优化 tree- cost的条件下 ,能够计算出满足延迟限制的、各目的节点公平负担网络代价的点到多点的组播路由树 .本文还给出一种近似算法 ,可减少节点间交换的信息量 ,同时在一般情况下仍保持各目的节点公平负担网络代价 .     

Probability based dynamic-alternate routing and the corresponding converter placement algorithm in all-optical WDM networks

This paper proposes a new dynamic-alternate routing algorithm and its corresponding converter placement algorithm in order to reduce the connection blocking probability for all-optical WDM networks. The main idea in the proposed dynamic-alternate routing algorithm is to try to route the traffics according to a predefined optimal probability distribution. The problem for finding the optimal probability distribution was shown as a convex optimization problem. The problem can be solved by flow deviation method or other standard optimization techniques. Simulation results show that the proposed routing algorithm yields lower connection blocking probabilities than the previous works. The proposed routing algorithm produces similar traffic pattern as the optimal traffic pattern. The similarity between the traffic pattern produced by the proposed dynamic-alternate routing algorithm and the optimal traffic pattern can be further employed for solving other network designing problems such as converter placement problem. Since the optimal traffic pattern can be easily predicted, the optimal traffic pattern which minimizes the blocked traffic intensity is utilized for finding the locations of wavelength converters. The key idea is to place the wavelength converters at the nodes where they are needed most. Simulations have been performed to study the performance of the proposed wavelength converter placement method. The simulation results have shown that the proposed placement method combined with the proposed probability based dynamic-alternate routing algorithm yields smaller connection blocking probability than the two converter placement methods with their corresponding alternate routing algorithms.     

基于遗传模拟退火算法的多约束QOS组播路由优化算法

组播路由问题在计算机网络中是著名的Steiner树问题,是NP完全问题.通过考虑组播通信服务质量需求与网络资源约束,研究了基于服务质量的组播路由选择算法问题,首次提出了一个基于遗传算法和模拟退火算法的多约束组播路由优化算法,该算法在满足带宽、延时、延时抖动及包丢失率约束条件下寻找代价最小的组播树.     

WDM全光网络中Multicast的寻径与波长分配算法

在WDM全光网络中实现实时Multicast功能是计算机网络的应用要求,也是现代计算机网络的重要特征。该文提出了一种在WDM全光网络中实现实时Multicast的算法。该算法以辅助的波长图为基础,将寻径与波长分配统一进行,构造满足延迟约束的、具有较低成本的Multicast树,实现Multicast功能。     

自组织覆盖网络QoS组播动态路由优化研究

针对覆盖组播节点的动态特性,研究自组织覆盖网络带度和延时约束的组播动态路由问题,提出了动态覆盖组播路由算法AHMQ。组播树由目的节点驱动动态渐近形成,动态路由优化在通信过程中进行。协议是软状态的,仅要求节点维护局部状态信息,同时利用覆盖网络技术和无线媒质的广播能力,降低了网络负载,提高了重构能力。对算法进行了分析研究,通过实验验证了该算法具有较好的性能。     

WDM网络中一种时延约束多播路由算法

文章提出了一种在有限波长转换器的WDM网络中,基于拉格朗日松驰的时延约束最小代价多播路由算法。该算法将WDM网络中的寻径与波长分配合成一步,并充分考虑到波长转换器的限制,利用拉格朗日松驰方法的特点,通过对松驰参数的变化得到每链路上的聚合代价,从而得到一棵近似于最优解的多播树。     

Dynamic routing and resource allocation in WDM transport networks

This contribution concentrates on dynamic routing in Wavelength Division Multiplexing (WDM) networks. It is shown that a strategy based on pre-calculated alternatives and an adaptive dynamic path search performs very well over a wide load range. Moreover, specific effects for the impact of resource allocation strategies in photonic WDM networks are highlighted, especially the influence of wavelength converter usage strategies in networks with partial conversion. The paper also investigates the way non-Poisson traffic behaviour affects performance of routing strategies and presents how the results from dynamic routing investigation can help to optimise the network planning process.     

WDM网状网中基于树路由的鲁棒抗毁算法研究*

研究了波分复用（WDM）网状网在软管不确定业务量模型下的鲁棒抗毁问题,提出一种新的基于树路由机制的共享分段保护算法——TSSP (tree-based shared-segment protection) 算法。利用软管模型下树路由机制的基本特征,TSSP算法首先计算出一个具有最小叶子节点数的工作树,然后根据恢复时间的要求为树上所有的叶子节点对寻找保护路径,最后借助共享保护的思想进行波长配备,从而达到优化网络性能的目的。仿真结果表明,相对于现有的鲁棒抗毁算法,TSSP不仅具有较小的全网代价,其恢复速度也较     

A genetic algorithm for solving virtual source placement problem on WDM networks

As WDM technology matures and multicast applications become increasingly popular, supporting multicast at the WDM layer becomes an important and yet challenging topic. In order to reduce the number of wavelength channels to achieve the multicast effectively, switching nodes with light-splitting and wavelength-converting capabilities denoted as virtual source (VS) nodes are developed. In this paper, given a WDM network, a positive integer k and a set of multicast requests, the VS placement (VSP) problem on WDM networks is studied; the goal is to determine the locations of the VS nodes, the multicast routing and assigned wavelengths of multicast requests so as to minimize the number of used wavelength channels. Since the VSP problem is a hard problem, a genetic algorithm (GA) is proposed to solve it. In the proposed GA, a binary-bit array is used to represent the locations of the VS nodes on network. For a given locations of VS nodes, three multicast routing methods: core-based tree (CBT), link-disjoint CBT (LDCBT), and layered graph (LG) are proposed and used to construct the shared tree for multicast requests. In the CBT and LDCBT methods, a multicast tree constructing (MTC) algorithm is used to construct the multicast tree of a given multicast, and a segment-based wavelength assignment (SBWA) algorithm is proposed and used to determine the assigned wavelength of the multicast tree. Moreover, in the proposed GA, several crossover and mutation operators are developed and used to generate offspring. Simulation results show that the proposed GA together with LG or CBT multicast method can get better results.