共查询到18条相似文献,搜索用时 125 毫秒
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研究了基于SRLG的光层保护的各种算法,在动态负载均衡算法基础上进行了改进,把共享子通路保护方式和动态链路权重配置算法结合在一起考虑,提出了负载均衡的共享子通路保护算法,使算法在符合SRLG限制的基础上,在动态负载均衡和故障倒换时间上都具备较理想的性能。 相似文献
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该文研究了WDM网状网中双链路失效问题,在假定所有链路共享风险链路组(Share Risk Link Group, SRLG)分离的条件下,提出了一种动态共享路径保护(Dynamic Shared-Path Protection,DSPP)算法。DSPP能根据网络状态动态调整链路代价,为每条业务请求选择一条最小代价的工作路由和两条最小代价且SRLG分离的保护路由。仿真表明,DSPP不仅能完全保护双链路失效,并且能在资源利用率、阻塞率和保护切换时间之间进行性能折衷。 相似文献
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抗毁WDM网中单SRLG故障的共享子通路保护 总被引:3,自引:0,他引:3
该文针对抗毁WDM网中单个共享风险链路组(Shared Risk Link Group,SRLG)故障,提出了一种动态共享子通路保护(Dynamic Shared Sub-Path Protection,DSSPP)算法.DSSPP为每条业务请求选择一条工作通路后,按照参数m把工作通路划分成若干条等长的子通路,其中m为子通路的长度,并为每条子通路各选择一条SRLG分离的保护通路.如果两条子通路SRLG分离,则它们对应的保护通路可以共享相同资源.在进行路由选择时,DSSPP考虑了负载均衡度和资源共享度,因此能有效地提高资源利用率和降低业务阻塞率.仿真表明,DSSPP不仅能保护单SRLG故障,而且能灵活地在资源利用率(阻塞率)和保护切换时间之间进行性能折衷. 相似文献
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WDM光网络中基于SRLG的共享通道保护策略 总被引:3,自引:1,他引:2
研究了动态业务下,WDM光网络的生存性。提出了一种单链路故障模型,并在此单链路故障模型下,考察了基于共享风险链路组(SRLG)的共享通道保护策略SRLG-SPP的保护性能,并把它同共享通道保护SPP和专用通道保护DPP的性能做了比较。 相似文献
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网状WDM网中支持区分可靠性的共享通路保护算法 总被引:2,自引:0,他引:2
光纤链路由于共享了某些物理资源(如光缆、管道、通路等),因此存在一定的故障相关性,术语“共享风险链路组(SRLG)”就是用于描述链路之间的这种风险共享关系的。SRLG分离成为保护设计的重要约束。该文研究了支持区分可靠性的SRLG分离共享通路保护设计问题。结合SRLG条件故障概率的概念,提出了部分SRLG分离的共享保护算法PSD-SPP(PartialSRLG-DisjointShared-PathProtection),有效地解决了SRLG分离约束下的区分可靠性设计问题。仿真结果表明该算法既满足了用户的区分可靠要求,又能有效利用资源。 相似文献
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本文研究了网状WDM网中的SRLG(Shared Risk Link Groups:共享风险链路组)分离约束下的静态共享通路保护设计问题-给定网络物理拓扑、业务量需求矩阵和工作路由,为每个波长需求确定保护路由,使得所需的备份资源最小.这个问题可以用整数线形规划公式来描述.由于这是一个NP-C问题,因此,本文提出一种启发式算法MSC(Maximally Share the Capacity)加以解决,该算法的核心思想是改变链路权重使得保护路由之间尽量共享资源.仿真结果表明,本文算法能有效地降低所需的备份资源,提高了网络的资源利用率. 相似文献
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Xu Shao Xiaofei Cheng Yong Kee Yeo Luying Zhou Yixin Wang Yuebin Bai 《Photonic Network Communications》2010,20(1):1-9
With the increase of size and number of shared risk link groups (SRLGs) in WDM networks, path protection tends to have longer working paths and backup paths due to SRLG-disjoint constraints, which makes physical impairment a major concern in working path and backup path provisioning, particularly in large-sized all optical networks. As a simple and efficient algorithm, the working path first algorithm is often used for path protection against SRLG failures, where the working path is calculated first by using the shortest-path algorithm on the graph, followed by using the SRLG-disjoint shortest path as backup path. Compared with the working path, the backup path calculated after the working path in the working path first algorithm is more vulnerable to physical impairment, since it may be much longer than the working path. As a result, if we reject those connections that cannot meet the physical impairment requirement, with SRLGs the blocking probability of path protection will be much higher. We argue that impairment must be taken into account together with capacity efficiency in a comprehensive way during SRLG-disjoint working path and backup path selection. To solve this problem, we motivate the needs to study physical impairment-aware shared-path protection by considering two policies. Policy I uses two SRLG-disjoint least impairment paths as working path and backup path, respectively, and Policy II tries to benefit from both the shortest path and the least impairment path by choosing them intelligently. Analytical and simulation results show: (1) compared with impairment-unawareness, impairment-aware SRLG failure protection performs much better in terms of blocking probability especially with strong physical impairment constraints; (2) impairment-aware SRLG failure protection can significantly reduce physical-layer blocking probability; and (3) the algorithm based on Policy II achieves a good balance between capacity efficiency and physical impairment requirement. 相似文献
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基于共享风险链路组(SRLG,shared risk link group)和P圈(P-Cycles,pre-configured cycles)的概念,研究了SRLG约束下p-Cycles的构造问题,引入SRLG完全分离p-Cycles的概念,基于SRLG的简单p-Cycles构造算法和获得更多p-Cycles的SRLG约束下的圈扩展算法提出的SRLG约束下的p-Cycles配置算法(SCAA),实现在光网络中优化配置SRLG完全分离的p-Cycles。通过计算机仿真表明,SCAA最小容量配置方案可以预留更少的网络资源,而SCAA优化容量配置方案可以实现p-Cycles快速配置容量,SCAA算法可以保障配置SRLG分离p-Cycles的高保护效能,使网络具备单SRLG故障恢复能力。 相似文献
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《AEUE-International Journal of Electronics and Communications》2007,61(6):353-362
This paper addresses the problem of shared path protection algorithm in survivable wavelength-division-multiplexing (WDM) optical networks, taking into consideration of differentiated reliability (DiR) under Shared-Risk-Link-Group (SRLG) constraint. A subset of network links that share the risk of failure at the same time are said to be in a common SRLG. Rather than the conventional complete SRLG-disjoint shared path protection, we introduce a heuristic Partial SRLG-disjoint Shared Path Protection algorithm (Pd-SPP) based on the concept of SRLG conditional failure probability, to provide differentiated reliability protection. The main target of our work is to improve the network resource utilization ratio under the DiR constraint. We adopt the ideas of partial SRLG-disjoint and the K-shortest paths algorithm such we can efficiently solve the “trap” problem. The experimental results show that our algorithm outperforms the complete SRLG-disjoint shared path protection in both blocking probability ratio and network resource utilization, i.e. the results are found to be promising. 相似文献
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Xu Shao Luying Zhou Xiaofei Cheng Chava Vijaya Saradhi Yixin Wang Jianqing Li 《Photonic Network Communications》2008,16(3):221-231
For 100% shared risk link group (SRLG) failure protection, conventional full path protection has to satisfy SRLG-disjoint
constraints, i.e., its working path and backup path cannot go though the same SRLG. With the increase of size and number of
SRLGs, capacity efficiency of conventional shared full path protection becomes poorer due to SRLG-disjoint constraints and
the blocking probability becomes much higher due to severe traps. To solve these problems, we present a partial path protection
scheme where SRLG-disjoint backup paths may only cover part of the working path. Full path protection becomes a special case
of partial path protection, in which the backup path covers the full working path. By choosing the most survivable partial
backup path as backup path, we can make the impact of SRLG failures as low as possible and accept as many as possible connection
requests. Assuming every SRLG has the same probability to fail, we present a heuristic algorithm to find the most survivable
partial backup path by choosing full path protection first, iteratively computing partial backup paths and choosing the most
survivable one. The benefit of this heuristic algorithm is that it can find the optimal results within less iteration. Analytical
and simulation results show that, compared to conventional full path protection, our proposed scheme can significantly reduce
blocking probability with little sacrifice on survivability. The proposed scheme is very useful particularly when the network
contains a lot of SRLGs and the blocking probability of conventional full path protection becomes too high.
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Jianqing LiEmail: |
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This letter proposes a disjoint path selection scheme for generalized multi-protocol label switching (GMPLS) networks with shared risk link group (SRLG) constraints. It is called the weighted-SRLG (WSRLG) scheme. It treats the number of SRLG members related to a link as part of the link cost when the k-shortest path algorithm is executed. In WSRLG, a link that has many SRLG members is rarely selected as the shortest path. Simulation results show that WSRLG finds more disjoint paths than the conventional k-shortest path algorithm. 相似文献