共查询到19条相似文献,搜索用时 796 毫秒
1.
2.
3.
针对IP over WDM网络,基于多跳光旁路和流量疏导,以减少能耗为目标对网络链路配置进行设计;考虑多跳光旁路会增大业务传输距离的问题,分析了光路建立顺序对业务传输距离的影响;通过优先路由短距离业务和限制最大传输跳数来减少业务的平均传输跳数。仿真结果表明,优先建立短距离光路的启发式算法与Dijkstra算法相比可以减少25%~55%的能耗,业务平均物理跳数与Dijkstra算法相差在1跳之内。 相似文献
4.
5.
针对虚拟环境下底层网络中光纤的概率性故障,传统的100%保护至少需要配置一条保护路径,造成资源冗余度高和虚拟网络请求接受率低的问题,该文提出一种基于安全性感知的差异化虚拟光网络的映射(SA-DVNM)策略,在链路发生故障时为差异化虚拟网络请求提供安全保证。在SA-DVNM策略中,设计了一个综合考虑物理节点对之间跳数和相邻带宽大小的节点权重式避免链路映射过长,并提出路径频谱资源使用均衡的链路映射机制,最小化瓶颈链路的数量。当单路径传输失败时,SA-DVNM策略设计允许路径分割的资源分配机制,为保障时延敏感业务的安全性,SA-DVNM策略在路由选择中设计了基于时延差优化的多路径路由频谱分配方法。仿真结果表明该文所提策略在概率故障环境中能够降低带宽阻塞率,提高频谱资源利用率和虚拟光网络接受率。 相似文献
6.
7.
8.
面对高速发展的互联网应用,传统的路由与频谱分配(RSA)问题迎来新的挑战。融合降级服务(DS)技术的弹性光网络无疑为降低业务阻塞率,提高用户体验质量(QoE)提供了新方向。该文首先针对频谱资源的低效利用和DS导致的业务收益下降问题,建立以最小化频谱消耗和最小化DS等级、频次为联合优化目标的RSA问题的混合整数线性规划模型。随后,提出一种基于区分DS和自适应调制的动态RSA算法。该算法考虑业务等级的差异化,并整合自适应调制和DS技术。同时,设计区分业务等级的DS损失函数及DS窗口选择策略,为即将受阻业务分配理想的频谱位置和资源。此外,设计考虑频谱与收益均衡关系的网络收益函数,达到频谱资源高效利用,减少降级影响,提升网络收益的目的。最后,仿真验证了所提算法在业务阻塞率和网络收益等方面的优势。 相似文献
9.
弹性光网络中多路径的保护方案相比单路径有效地降低网络带宽阻塞率,但会导致接收端多径时延差的问题,且业务的多路径分割传输策略使用了光网络较多的频谱资源。该文基于多目标遗传算法提出了遗传多路径保护算法(Genetic Multipath Protection Algorithm, GMPA),解决多路径时延差和节约频谱资源问题。在GMPA算法中,根据业务请求在光网络中建立K条边分离最短路径和带宽分配方案作为GMPA算法的初始种群,设计了一种联合考虑传输时延差和带宽资源分配的向量函数优化种群分类和拥挤距离排序。为提高算法的搜索能力和收敛速度,算法在交叉操作中设计个体自交叉方式,在变异过程中设置了带宽基因位变异范围及约束条件。仿真结果表明,相比多路径保护(Multiple Path Protection, MPP)算法和工作路径首次分配保护路径最后分配(Primary First-fit Modified Backup Last-fit, PF-MBL) 算法,GMPA算法获得最低的带宽阻塞率,其频谱资源利用率接近最优的MPP算法,路径间距离差异性能优于MPP算法。 相似文献
10.
自适应的认知无线Mesh网络QoS约束的路由与频谱分配算法 总被引:1,自引:0,他引:1
提出了一种自适应的满足QoS约束的路由与频谱分配(SA2JR)算法,SA2JR的目标是:在满足无线业务QoS约束的情况下,最大化无线业务接受率,让尽可能多的无线业务需求能够被满足.SA2JR包括2个部分,按需的κ-路径路由(κ-Routing)算法,以及QoS驱动的频谱分配(QDSA)算法.κ-Routing负责为每一个需求产生κ条潜在路由路径,QDSA算法自适应地进行频谱分配,目标是从κ-Routing产生的κ条潜在路由路径中找出一条满足QoS约束的可行路由路径.仿真结果表明SA2JR能达到预定目标,获得了较高的无线业务接受率. 相似文献
11.
Constantine A. Kyriakopoulos Georgios I. Papadimitriou Petros Nicopolitidis 《International Journal of Communication Systems》2018,31(13)
Elastic optical networks offer a reliable platform for achieving energy efficiency by supporting extensive optical grooming of variable‐rate data traffic along with the traditional electrical data aggregation methods. The procedure of routing and spectrum allocation in a topology of nodes has explicit effect to the amount of consumed power. A new energy‐efficient method for designing the virtual topology in IP‐over‐elastic networks is introduced and evaluated. It is concluded that it consumes less power under different elastic transponder types, it designs the virtual topology using fewer transponders, and finally, there is a slight increase in the number of end‐to‐end lightpath hops. The proposed method is characterized by high performance and low lightpath establishment complexity. Therefore, it is suitable for a broad range of network configurations and transponder types. 相似文献
12.
Cunqian Yu Weigang Hou Ying Wu Jingjing Wu Zhimin Sun 《Photonic Network Communications》2016,31(3):524-531
In order to mitigate the mismatch of granularities between fixed grid and client traffic, the elastic optical network (EON) was proposed by using orthogonal frequency division multiplexing. In EONs, the bandwidth variable transponder adjusts the number of bits per symbol, so that an optical signal generates by using just enough sub-carriers each with appropriate modulation level. Owing to the advantage of line-rate adaption above, the application of cloud computing has witnessed rapid growth in EONs. However, bandwidth variable transponders consume more power compared with ordinary ones, which will lead to a power-thirsty EON if no effective measure is taken. As a result, the green grooming was proposed for EONs. Unfortunately, the adaptive multilevel modulation was neglected in the current works focusing on green grooming. Thus, in this paper, we design a novel modulation adaptive grooming with guaranteeing transmission performances in green EONs. The distance-adaptive spectrum resource allocation is applied to the green grooming algorithm previously designed by us for EONs. The simulation results show that the adaptive multilevel modulation plays an important role on saving spectrum and power consumption for the green grooming in EONs, because the spectral bandwidth can be saved by increasing the number of bits per symbol to transmit the same data rate. 相似文献
13.
In order to improve the bandwidth utilization efficiency and reduce the blocking probability for multicast requests in optical networks, the multicast traffic grooming approach was proposed to groom a lot of low-speed traffic to a few of high-speed light-trees. At the same time, in order to save the ports and the cost of optical cross-connect, the multicast waveband grooming approach was proposed to groom multiple light-trees to a few of waveband tunnels. However, the existing approaches all did not consider the joint performances of improving bandwidth utilization efficiency, reducing blocking probability and saving ports for multicast requests. Therefore, in this article, we propose a new multicast multi-granular grooming approach to perform the hierarchical sequential grooming to improve the joint performances based on a newly developed integrated auxiliary grooming graph (IAGG) that includes multiple wavelength integrated grooming graphs (WIGGs) and one waveband virtual topology layered graph (BVLG) to support both the multicast traffic grooming and multicast waveband grooming. In order to achieve the map of light-tree to the virtual topology layer in WIGG or BVLG, we present a light-segment map method, where a light-tree will be divided to several light-segments each of which will be independently mapped to the virtual topology layer. Since different definitions of blocking probability may lead to different objectives, we define two kinds of blocking probability, mean blocking probability of requests (MBPR) and mean blocking probability of users (MBPU). According to the two definitions of blocking probability, we propose two multicast multi-granular grooming heuristic algorithms, Heuristic Algorithm with minimizing MBPR and Heuristic Algorithm with minimizing MBPU based on IAGG. Simulation results show that the two proposed algorithms are both efficient and have better performances than traditional multicast grooming algorithm. 相似文献
14.
In wavelength routed optical networks, the number of wavelength channels is limited due to several constraints and each wavelength
as well as each lightpath support traffic in the Gbps range. On the other hand, the traffic requested by an individual connection
is still in the Mbps range. Therefore, to utilize the network resources (such as bandwidth and transceivers) effectively,
several low-speed traffic streams have to be efficiently groomed or multiplexed into one or more high-speed lightpaths. The
grooming problem of a static demand is considered as an optimization problem. In this work, we have investigated the traffic
grooming problem with the objective of maximizing the network throughput for wavelength-routed mesh networks and map this
problem to the clique partitioning problem. We have proposed an algorithm to handle general multi-hop static traffic grooming
based on the clique partitioning concept. The efficiency of our approach has been established through extensive simulation
on different sets of traffic demands with different bandwidth granularities for different network topologies and compared
the approach with existing algorithms. 相似文献
15.
Dynamic provisioning of low-speed unicast/multicast traffic demands in mesh-based WDM optical networks 总被引:2,自引:0,他引:2
Khalil A. Hadjiantonis A. Assi C.M. Shami A. Ellinas G. Ali M.A. 《Lightwave Technology, Journal of》2006,24(2):681-693
This paper addresses the problem of dynamically provisioning both low-speed unicast and multicast connection requests in mesh-based wavelength division multiplexing (WDM) optical networks. Several routing/provisioning schemes to dynamically provision both unicast and multicast connection requests are presented. In addition, a constraint-based grooming strategy is devised to utilize the overall network resources as efficiently as possible. Based on this strategy, several different sequential multicast grooming heuristics are first presented. Then, we devise a hybrid grooming approach and combine it with sequential approaches to achieve a grooming scheme that is biased toward serving multicast traffic demands in comparison with all other sequential grooming approaches. To achieve our objective, we decompose the problem into four subproblems: 1) routing problem; 2) light-tree-based logical-topology-design problem; 3) provisioning problem; and 4) traffic-grooming problem. The simulation results of the proposed schemes are compared with each other and with those of conventional nongrooming approaches. To the best of our knowledge, this is the first detailed paper to address and examine the problem of grooming dynamic multicast traffic demands. 相似文献
16.
为了获得高效的网络生存性能,基于自动交换光网络(ASON)的框架,该文提出了一种新型的可恢复路径选择算法-联合可变权重可恢复路径(JVWR)选择算法,并进行了数值仿真分析,仿真结果表明,此恢复路径选择算法具有明显的业务量均衡能力,并降低了动态连接请求的阻塞概率,同时具有良好的带宽利用率和恢复资源共享效率。该文还对mesh网络业务路径和恢复路径的建立机制进行了讨论,在ASON功能框架之内,基于通用多协议标记交换提出了并行mesh共享恢复路径建立机制,从而较系统地对分布式恢复路径动态建立机制进行了研究。 相似文献
17.
18.
《Optical Fiber Technology》2014,20(4):341-352
This paper proposes an efficient overlay multicast provisioning (OMP) mechanism for dynamic multicast traffic grooming in overlay IP/MPLS over WDM networks. To facilitate request provisioning, OMP jointly utilizes a data learning (DL) scheme on the IP/MPLS layer for logical link cost estimation, and a lightpath fragmentation (LPF) based method on the WDM layer for improving resource sharing in grooming process. Extensive simulations are carried out to evaluate the performance of OMP mechanism under different traffic loads, with either limited or unlimited port resources. Simulation results demonstrate that OMP significantly outperforms the existing methods. To evaluate the respective influences of the DL scheme and the LPF method on OMP performance, provisioning mechanisms only utilizing either the IP/MPLS layer DL scheme or the WDM layer LPF method are also devised. Comparison results show that both DL and LPF methods help improve OMP blocking performance, and contribution from the DL scheme is more significant when the fixed routing and first-fit wavelength assignment (RWA) strategy is adopted on the WDM layer. Effects of a few other factors, including definition of connection cost to be reported by the WDM layer to the IP/MPLS layer and WDM-layer routing method, on OMP performance are also evaluated. 相似文献
19.
Traditional ROADM networks strictly follow the coarse ITU-T standard wavelength grids and channel spacings, which would result in low optical spectrum utilizations under dynamic traffic requests of variable spectrum lightpaths. This paper presents a spectrum-efficient optical drop-add-drop network with a centralized multi-carrier light source (C-MCLS). The C-MCLS generates thousands of optical carriers with uniform and narrow channel spacings. The optical carriers are distributed to each network node as light sources on demand through ROADMs designed with the carrier-drop function. Spectrum-aware optical carrier allocation is studied first in the proposed network. This paper proposes a Minimum Fragmentation Request First (MinFragRF) optical carrier allocation algorithm compared with the Maximum Spectrum Request First (MaxSRF) and Minimum Spectrum Request First (MinSRF) allocation algorithms. This paper also studies how channel spacings of optical carriers impact on the network performance under variable traffic demands. We perform both network analysis and simulations to evaluate the network performance in terms of the lightpath blocking probability (LP_BP) and the effective spectrum efficiency. We analytically derive the formulas of LP_BP and average effective spectrum efficiency in the proposed network. Simulation results show that the proposed network with more narrow channel spacings greatly reduces the lightpath blocking probability compared with the traditional ROADM network. The average effective spectrum efficiency of the proposed network can be improved about 100 % compared with that of the traditional ROADM network by choosing appropriate network design parameters. The MinFragRF allocation algorithm has a better LP_BP performance than that of the MaxSRF and has a better spectrum utilization efficiency than that of the MinSRF. The optimal channel spacing evaluations show that narrow channel spacings such as 6.25 and 12.5 GHz greatly improve LP_BP performance when low bit-rate traffic requests dominate in the traffic model. However, as the high bit-rate traffic requests increase, the performance advantage of narrow channel spacings is gradually disappearing. 相似文献