共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
4.
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
5.
在波分复用(WDM)光网络中,文章将经过各节点的最短路径的总长度作为权值对节点进行排序,利用优先配置最短路径总长度较长的节点的思想,对已有的"子图+ 代数决策图(ADD)"算法进行改进,得到了一种新的"子图+路径长度排序 (PLS)"算法.对两种算法进行了计算机仿真,结果显示新算法在保证结果准确的同时,较有效地降低了运算的时间复杂度. 相似文献
6.
7.
8.
Quang-Dzung Ho Man-Seop Lee 《Communications Letters, IEEE》2006,10(3):198-200
In wavelength-routed optical networks (WRONs), a wavelength assignment algorithm which can optimally utilize wavelength converters is strongly desired. In this letter, for the first time, we propose a novel graph constructed with groups of available wavelengths, called lambda-runs, to obtain the least-conversion lightpaths easily by applying the shortest-path routing Dijkstra's algorithm. Simulations show that our algorithm is much more scalable than an existing optimal algorithm, and significantly improves the blocking performance, compared to modified first-fit algorithm. 相似文献
9.
10.
文章在一种已有的"子图+ADD(代数决策图)"的波长转换器配置算法的基础上,提出了用优先配置最大度节点的启发式思想对该算法进行改进,得到了新的"子图+BDF(大度节点优先分配)"算法.通过对两种算法进行计算机仿真,得到的模拟结果显示新算法在保持结果准确的同时,有效降低了运算的时间复杂度. 相似文献
11.
In this paper, we consider wavelength rerouting in wavelength routed wavelength division multiplexed (WDM) networks with circuit switching, wherein lightpaths between source-destination pairs are dynamically established and released in response to a random pattern of arriving connection requests and connection holding times. The wavelength continuity constraint imposed by WDM networks leads to poor blocking performance. Wavelength rerouting is a viable and cost effective mechanism that ran improve the blocking performance by rearranging certain existing lightpaths to accommodate a new request. Recently, a rerouting scheme called “parallel move-to-vacant wavelength retuning (MTV-WR)” with many attractive features such as shorter disruption period and simple switching control, and a polynomial time rerouting algorithm, for this scheme, to minimize the weighted number of rerouted lightpaths have been proposed. This paper presents a time optimal rerouting algorithm for wavelength-routed WDM networks with parallel MTV-WR rerouting scheme. The algorithm requires only O(N2W) time units to minimize the weighted number of existing lightpaths to be rerouted, where N is the number of nodes in the network and W is the number of wavelength channels available on a fiber link. Our algorithm is an improvement over the earlier algorithm proposed in that it requires O(N3W+N2W2) time units, which is not time optimal. The simulation results show that our algorithm improves the blocking performance considerably and only very few lightpaths are required to be rerouted per rerouting. It is also established through simulation that our algorithm is faster than the earlier rerouting algorithm by measuring the time required for processing connection requests for different networks 相似文献
12.
Routing and wavelength assignment in WDM all-optical networks 总被引:3,自引:0,他引:3
Kyungsik Lee Sungsoo Park Kyung-Il Choe Cheehang Park 《Electronics letters》2000,36(11):964-966
A new mathematical formulation of the routing and wavelength assignment in wavelength division multiplexing (WDM) all-optical networks is proposed. Which yields tight linear programming lower bounds on the wavelength requirements both theoretically and computationally. An efficient procedure computing lower bounds is also presented together preliminary computational results. 相似文献
13.
14.
15.
In this article, a genetic evolutionary algorithm is proposed for efficient allocation of wavelength converters in WDM optical
networks. Since wavelength converters are expensive, it is desirable that each node in WDM optical networks uses a minimum
number of wavelength converters to achieve a near-ideal performance. The searching capability of genetic evolutionary algorithm
has been exploited for this purpose. The distinguished feature of the proposed approach lies in handling the conflicting circumstances
during allocation of wavelength converters considering various practical aspects (e.g., spatial problem, connectivity of a
node with other nodes) rather than arbitrarily to possibly improve the overall blocking performance of WDM optical networks.
The proposed algorithm is compared with a previous approach to establish its effectiveness and the results demonstrate the
ability of the proposed algorithm to efficiently solve the problem of Optimal Wavelength Converters Allocation (OWCA) in practical
WDM optical networks.
相似文献
Mrinal K. NaskarEmail: |
16.
For the purpose of reducing the complexity and cost of optical large-scale cross-connect, wavelengths are grouped into wavebands
or fiber to be switched as a single entity, which is called multi- granularity switching. However, it introduces more complexity
into the routing and wavelength assignment problem. In this paper, we propose a novel graph model for describing the states
of the multi-granularity switching WDM networks. Based on the model, the dynamic routing and wavelength assignment problems
for multi-granularity traffic can be solved jointly, and different on-line wavelength grooming policies can be achieved simultaneously.
By simulation, we compared the performance of our algorithms under different policy and different percent of fibers for fiber
switching. The result proved that our algorithms yield better performance than those deal with the routing and wavelength
assignment separately.
This work was supported in part by NSFC Project No. 90104003, 60272023, 60372025 and National 863 project No. 2005AA122310. 相似文献
17.
18.
Peiyuan Lee Yongtao Gong Wanyi Gu 《Communications Letters, IEEE》2004,8(6):397-399
This letter studies routing and wavelength assignment (RWA) problem in wavelength-routed wavelength-division multiplexing networks with both uniform and nonuniform traffic model. Our research shows that the potential traffic load information is a crucial factor for routing algorithm design. Based on our analysis, an adaptive RWA algorithm is proposed. The simulation shows that the proposed algorithm performs much better than other adaptive RWA algorithms. 相似文献
19.
We consider the problem of wavelength assignment in reconfigurable WDM networks with wavelength converters. We show that for N-node P-port bidirectional rings, a minimum number of /spl lceil/PN/4/spl rceil/ wavelengths are required to support all possible connected virtual topologies in a rearrangeably nonblocking fashion, and provide an algorithm that meets this bound using no more than /spl lceil/PN/2/spl rceil/ wavelength converters. This improves over the tight lower bound of /spl lceil/PN/3/spl rceil/ wavelengths required for such rings given in if no wavelength conversion is available. We extend this to the general P-port case where each node i may have a different number of ports P/sub i/, and show that no more than /spl lceil//spl sigma//sub i/P/sub i//4/spl rceil/+1 wavelengths are required. We then provide a second algorithm that uses more wavelengths yet requires significantly fewer converters. We also develop a method that allows the wavelength converters to be arbitrarily located at any node in the ring. This gives significant flexibility in the design of the networks. For example, all /spl lceil/PN/2/spl rceil/ converters can be collocated at a single hub node, or distributed evenly among the N nodes with min{/spl lceil/P/2/spl rceil/+1,P} converters at each node. 相似文献
20.
针对光核心传送网中单纤场景下的路由选择与波长分配(Routing and Wavelength Assignment,RWA)问题,提出了一种邻域加权累积的波长分配策略。在一条路径上为一个连接请求选择波长时,将网络的所有链路归入当前路径的不同邻域中,然后根据与路径之间的距离为不同邻域赋予不同的权重,进而对每个波长在全网中被占用的个数进行加权累积,最后选择累积值最大的可用波长建立连接。仿真结果表明,相对于现有的阻塞率最低的最大使用(Most-Used)波长分配策略,所提策略具有更低的阻塞率。 相似文献