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WDM网络中支持QoS的路由与波长分配算法 总被引:1,自引:1,他引:1
针对波分复用(wDM)网络中的路由与波长分配问题。提出了一种支持服务质量(QoS)的约束搜索算法。基于多目标规划模型,这种搜索算法可为网络各节点创建路由表,根据路由表信息求出非支配路径集合,从而一次性完成寻找路由和分配波长两项任务。仿真实例证明了该算法的有效性。 相似文献
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一种多约束QoS多播路由算法 总被引:2,自引:0,他引:2
提出了带宽时延约束、代价最小的QoS多播路由模型,并提出了一种启发式算法求解该问题,分析了算法的复杂度。仿真试验证明,该算法是稳定有效的。它能够在满足两种约束的情况下,使多播树的代价优化。 相似文献
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基于免疫--蚂蚁算法的多约束QoS路由选择 总被引:5,自引:0,他引:5
针对多约束QoS路由选择问题,将其转化为一个多约束赋权图最短路径问题,选择费用、带宽、时延、丢失率为QoS参数。借鉴人体免疫系统的适应能力和蚂蚁算法的全局寻优能力提出了一种新的融合算法即免疫——蚂蚁算法。免疫算法把目标函数和制约条件作为抗原,目标函数的优化解对应为抗体,使得求解过程的收敛方向得以控制;利用蚂蚁算法产生和更新抗体,抗体交叉、变异操作以及对与抗原亲和力高的抗体进行记忆,均能促进快速求解。实验结果表明:免疫——蚂蚁算法表现出了超越免疫算法和蚂蚁算法的优点,大幅度提高了路由选择的效率。 相似文献
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In this paper, we investigate the issues of QoS multicast routing in wireless ad hoc networks. Due to limited bandwidth of a wireless node, a QoS multicast call could often be blocked if there does not exist a single multicast tree that has the requested bandwidth, even though there is enough bandwidth in the system to support the call. In this paper, we propose a new multicast routing scheme by using multiple paths or multiple trees to meet the bandwidth requirement of a call. Three multicast routing strategies are studied, SPT (shortest path tree) based multiple-paths (SPTM), least cost tree based multiple-paths (LCTM) and multiple least cost trees (MLCT). The final routing tree(s) can meet the user’s QoS requirements such that the delay from the source to any destination node shall not exceed the required bound and the aggregate bandwidth of the paths or trees shall meet the bandwidth requirement of the call. Extensive simulations have been conducted to evaluate the performance of our three multicast routing strategies. The simulation results show that the new scheme improves the call success ratio and makes a better use of network resources. 相似文献
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Current quality of service (QoS) routing schemes for low earth orbit (LEO) satellites IP networks either neglect the varying population density or fail to guarantee end-to-end delay. As a remedy, QoS routing protocol based on mobile agent (QoSRP-MA) is proposed. QoSRP-MA is a source-based routing protocol. Once connection requests arrive, QoS mobile agents are dispatched from ingress satellite to explore routes, which migrate using satellite routing tables. Upon arriving in egress satellite, QoS mobile agents migrate back towards ingress satellite to reserve bandwidth. To construct satellite routing tables, load balancing routing algorithm based on mobile agent (LBRA-MA) is presented. In LBRP-MA, at regular intervals mobile agents launched on all satellites migrate autonomously to evaluate path cost and update routing tables. Moreover, path cost between source and destination is evaluated considering satellite geographical position as well as inter-satellite link (ISL) cost. Furthermore, ISL congestion index is considered to update routing table. Through simulations on a Courier-like constellation, it shows that QoSRP-MA can achieve guaranteed end-to-end delay bound with higher throughput, lower connection failing ratio and signaling overhead compared to high performance satellite routing (HPSR) scheme. 相似文献
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通过建立光通信网络系统状态的Markov模型和状态转移矩阵,利用稳态Markov模型状态转移概率平衡特点计算网络系统稳态概率;再根据网络拓扑结构和保护机制信息,通过概率计算得到了系统稳态概率。在对光通信网络系统稳态概率做出评估的基础上,提出了一种自由空间光通信网络的路由算法。该算法考虑了网络节点的快速移动特性、链路带宽、最短路径以及节点收发器数目的限制。仿真实验研究表明,经过系统稳态概率评估的路由算法在实际应用过程中在可靠性、稳定性等方面均优于一般路由算法。 相似文献
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Noureddine Kettaf Hafid Abouaissa Thang Vu duong Pascal Lorenz 《Telecommunication Systems》2006,33(1-3):255-267
Providing guaranteed quality of service (QoS) in wireless networks is a key issue for deploying multimedia applications. To
support such a QoS, an arduous problem concerning how to find a feasible end to end path to satisfy multiple QoS constraints
should be studied. In general, multi-constrained path selection, with or without optimization, is an NP-complete problem that
cannot be exactly solved in polynomial time. Approximation algorithms and heuristics with polynomial and pseudo-polynomial
time complexities are often used to deal with this problem. However, existing solutions suffer either from excessive computational
complexities that cannot be used for multimedia applications in ad hoc networks characterized by mobility and performance
constraints (e.g., limited energy, wireless medium, etc.). Recently a promising heuristic algorithm H_MCOP using a non linear
Lagrange relaxation path functions has demonstrated an improvement in its success rate and in finding feasible paths. However,
the H_MCOP is not suitable for ad hoc networks and has not exploited the full capability that a Lagrange relaxation could
offer. In this paper, we propose an efficient multi-constrained path heuristic called E_MCP, which exploits efficiently the
Lagrange relaxation and enhances the path search process to be adequate to mobile ad hoc networks. Using extensive simulations
on random mobile network with correlated and uncorrelated link weights, we show that the same level of computational complexity,
E_MCP can achieve a higher success ratio of finding feasible paths. 相似文献
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WDM全光网自适应路由和波长分配算法 总被引:4,自引:1,他引:3
研究了无波长转换WDM全光网的路由和波长分配算法(RWA)。通过对已有算法的分析和比较,提出了一种自适应最小跳数路由算法(ADMH)。此算法以最小跳数路由为基础,同时考虑网络状态的变化,因而不仅能尽量少使用网络资源,也能使网络资源的分布保持均衡。计算机模拟仿真的结果表明,这种算法性能在各种网络参数条件下优于或等于已有算法。 相似文献
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Kyriakos Vlachos Erik Van Breusegem Kostas Christodoulopoulos Didier Colle Kostas Ramantas Piet Demeester 《Photonic Network Communications》2007,13(3):227-240
In this article, we present a detailed performance evaluation of a hybrid optical switching (HOS) architecture called Overspill
Routing in Optical Networks (ORION). The ORION architecture combines (optical) wavelength and (electronic) packet switching,
so as to obtain the individual advantages of both switching paradigms. In particular, ORION exploits the possible idle periods
of established lightpaths to transmit packets destined to the next common node, or even directly to their common end-destination.
Depending on whether all lightpaths are allowed to simultaneously carry and terminate overspill traffic or overspill is restricted
to a sub-set of wavelengths, the architecture limits itself to constrained or un-constrained ORION. To evaluate both cases, we developed an extensive network simulator where the basic features of the ORION architecture
were modeled, including suitable edge/core node switches and load-varying sources to simulate overloading traffic conditions.
Further, we have assessed various aspects of the ORION architecture including two basic routing/forwarding policies and various
buffering schemes. The complete network study shows that ORION can absorb temporal traffic overloads, as intended, provided
sufficient buffering is present. We also demonstrate that the restriction of simultaneous packet insertions/extractions, to
reduce the necessary interfaces, do not deteriorate performance and thus the use of traffic concentrators assure ORION’s economic viability. 相似文献
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基于节点功能的WDM光网络分布式路由与波长分配算法 总被引:2,自引:0,他引:2
建立了一种具有节点功能区分的WDM多波长光网络模型,根据节点功能将其分为A、B两类,在此基础上提出了波长等价弧和等价网络等概念,并根据此类多波长光网络模型的节点和网络结构特点以及相应的选路和波长分配策略,提出了一种基于节点功能的多波长光网络分布式路由与波长分配算法——BONF算法,证明了算法的可行性,分析了算法的计算复杂度,比较了此算法与其它同类型算法的区别,指出了BONF算法的优点和不足。 相似文献
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全光网静态路由选择和波长分配的分层图算法 总被引:1,自引:0,他引:1
文章提出一种将路由选择和波长分配结合起来的启发式的路由选择和波长分配(RWA)算法.通过这种新的分层图算法和限制光跳距的加权系数来优化全光网的静态路由选择和波长分配,使建立光连接时所需的波长数达到最少.最后对实际的ARPANet等5种光网络进行了计算机仿真,证明了本算法比以前的算法有更好的性能. 相似文献