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1.
As networks grow in size and complexity, both the probability and the impact of failures increase. The pre-allocated backup
bandwidth cannot provide 100% protection guarantee when multiple failures occur in a network. In this article, we focus on
how to recover the protecting capabilities of FIPP (Failure-independent path-protecting) p-cycles against the subsequent links
failure on WDM networks, after recovering the working paths affected by the failure of link. Two recovering policies are designed
to recover the protecting capabilities of the FIPP p-cycles if possible, unless there is no sufficient network resource. They
are Cycle Recovery Policy and Path Recovery Policy. In addition, a Cycle Adjust algorithm is proposed and used to recover the affected cycles. The simulation results of the proposed methods are also given. 相似文献
2.
Protection techniques for optical networks mainly rely on pre-allocated backup bandwidth, which may not be able to provide full protection guarantee when multiple failures occur in a network. After recovering from the previous failure, if failure occurs again, unprotected or vulnerable lightpaths cannot be recovered. In this paper, the minimal backup reprovisioning (MBR) problem is studied, in which, the node-encircling protecting cycles (NEPCs) scheme is considered for single node-failure on WDM networks. The NEPC Recovery Algorithm is proposed to recover the protecting capabilities of the NEPC. Simulation results show that the performance of the proposed method is better than that of the traditional one. 相似文献
3.
《Optical Fiber Technology》2014,20(2):142-157
As networks grow in size and complexity, the chance and the impact of failures increase dramatically. The pre-allocated backup resources cannot provide 100% protection guarantee when continuous failures occur in a network. In this paper, the multicast backup re-provisioning problem (MBRP) for Hamiltonian cycle (HC)-based protection on WDM networks for the link-failure case is studied. We focus on how to recover the protecting capabilities of Hamiltonian cycle against the subsequent link-failures on WDM networks for multicast transmissions, after recovering the multicast trees affected by the previous link-failure. Since this problem is a hard problem, an algorithm, which consists of several heuristics and a genetic algorithm (GA), is proposed to solve it. The simulation results of the proposed method are also given. Experimental results indicate that the proposed algorithm can solve this problem efficiently. 相似文献
4.
Der-Rong Din Chi-Yen Hung Yu-Cyuan Chen Hung-Yin Wang Chung-Yang Tu 《Photonic Network Communications》2012,23(1):40-52
In this article, for the given wavelength division multiplexing (WDM) network, the demand traffic matrix, the old and new survivable virtual topologies which are protected by the failure-independent path-protecting p-cycles (FIPP p-cycles) protection scheme, the virtual topology transition sequence (VTTS) problem is studied. The goal of this problem is to find an optimal sequence to transfer the old virtual topology into
new one, and during the transiting process, the services are not disrupted. Moreover, each lightpath in the virtual topology
is protected by the FIPP p-cycle and can survive against a single-link failure. In this article, a heuristic algorithm and
a genetic algorithm are proposed to solve this problem. Simulations are also performed to evaluate the performance of proposed
algorithms. 相似文献
5.
We consider a new heuristic method for design of survivable wavelength-division multiplexing (WDM) networks with preconfigured protection cycles (p-cycles). Numerical studies show that the new heuristic works well for different traffic patterns, and the spare capacity obtained by the new heuristic is very close to that of the optimal solution but with much reduced computational time. 相似文献
6.
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
7.
Pre-configured cycles (p-cycles) can attain high capacity efficiency and fast protection switching times in wavelength division multiplexing (WDM) networks.This article proposes the weighted straddling link algorithm (WSLA) for generating a subset of all cycles that can guarantee 100% restorability in case of dual link failure, and give an integer linear programming (ILP) formulation that solves the shared p-cycles design problem minimizing the total spare capacities.Numerical result shows that our method can achieve 100% dual link failure restorability with acceptable spare capacity.The larger standard deviation of demand set and the larger node degree network, the better the shared p-cycles scheme performs. 相似文献
8.
Dimensioning of survivable WDM networks 总被引:7,自引:0,他引:7
Van Caenegem B. Van Parys W. De Turck F. Demeester P.M. 《Selected Areas in Communications, IEEE Journal on》1998,16(7):1146-1157
In this paper routing, planning of working capacity, rerouting, and planning of spare capacity in wavelength division multiplexing (WDM) networks are investigated. Integer linear programming (ILP) and simulated annealing (SA) are used as solution techniques. A complex cost model is presented. The spare capacity assignment is optimized with respect to three restoration strategies. The benefit of wavelength conversion, the choice of the fiber line system, and the influence of cost parameter values are discussed, with respect to the different restoration strategies and solution techniques. Wavelength conversion is found to be of limited importance, whereas tunability at the end points of the connections has substantial benefits 相似文献
9.
Differentiated QoS for survivable WDM optical networks 总被引:1,自引:0,他引:1
Optical networks based on WDM technology have become a promising solution to realize transport networks that can meet the ever-increasing demand for bandwidth. As WDM networks carry a huge volume of traffic, maintaining a high level of survivability is an important and critical issue. The. development of GMPLS switching technology led to the direct integration of IP and WDM. In these IP-over-WDM networks different applications/end users need different levels of fault tolerance and differ in how much they are willing to pay for the service they get. The current trend in network development is moving toward a unified solution providing support for voice, data, and various multimedia services. Therefore, it imperative that WDM networks incorporate fault tolerance to single or multiple component failures, protection bandwidth, recovery time, and recovery granularity besides resource utilization and call acceptance ratio. This article presents a survey of various methods that have been proposed for providing service differentiation in survivable WDM networks and discuss their performance. Such methods are broadly classified under various paradigms such as differentiated reliability, R-connections, quality of protection, and quality of recovery. 相似文献
10.
11.
Lei Guo Xingwei Wang Jiannong Cao Xiaobing Zheng 《Photonic Network Communications》2009,18(3):393-399
In this paper, we propose a new survivable algorithm, called Enhanced Shared-Path Protection (ESPP), to tolerate multi-link
failures in WDM optical networks. In ESPP, we consider the load balancing method to reduce the blocking probability for computing
the primary paths, and we also use the idea of backup resources sharing to save backup resources for computing the backup
paths. In order to tolerate multi-link failures, we perform the recovery escalation mechanism to establish new routes for
carrying the traffic affected by the failures. Simulation results show that, compared with the conventional algorithm, ESPP
has better resource utilization ratio, lower blocking probability, and higher protection ability. 相似文献
12.
This article proposes a new heuristic algorithm, called Shared Multi-sub-backup-paths Reprovisioning (SMR), to improve the
survivability for multi-link failures in WDM mesh networks. In SMR, each connection will be initially assigned one primary
path, one backup path, and multiple sub-backup paths. When failures occur, based on the corresponding policy SMR will reprovision
the primary or backup resources for these connections affected by the failures. Compared to previous algorithms, the survivable
performance of SMR can be significantly improved.
The short version of this article was presented at the International Workshop on Broadband Convergence Networks (BCN) 2007. 相似文献
13.
Der-Rong Din Chian-Ya Hong Hsiao-Suang Yen Ya-Hsin Chuang Xin-Kai Lin 《Photonic Network Communications》2013,26(2-3):150-160
For a delay-constrained multicast transmission request, the goal of delay-constrained survivable multicast routing problem is to provide the primary multicast tree and the tree protecting sparse resources. The shared segment-based protection (SSBP) method is used in this article to protect the delay-constrained multicast transmission. Two heuristic methods are proposed to find the delay-constrained primary tree and the backup segments with delay constraint. Experiments are conducted to evaluate the performance of the proposed methods, and the performance to be evaluated includes wavelength efficiency ratio (WER), blocking ratio (BR), and executing time. Simulations show that the SSBP method can get better BR and WER than the previous results demonstrated Din and Jiang (Comput Commun 35(10):1172–1184, 2012). 相似文献
14.
Traffic grooming for survivable WDM networks - shared protection 总被引:4,自引:0,他引:4
Canhui Ou Keyao Zhu Hui Zang Sahasrabuddhe L.H. Mukherjee B. 《Selected Areas in Communications, IEEE Journal on》2003,21(9):1367-1383
We investigate the survivable traffic-grooming problem for optical mesh networks employing wavelength-division multiplexing (WDM). In the dynamic provisioning context, a typical connection request may require bandwidth less than that of a wavelength channel, and it may also require protection from network failures, typically fiber cuts. Based on a generic grooming-node architecture, we propose three approaches for grooming a connection request with shared protection: protection-at-lightpath level (PAL); mixed protection-at-connection level (MPAC); separate protection-at-connection level (SPAC). In shared-mesh protection, backup paths can share resources as long as their corresponding working paths are unlikely to fail simultaneously. These three schemes explore different ways of backup sharing, and they trade-off between wavelengths and grooming ports. Since the existing version of the problem for provisioning one connection request with shared protection is NP-complete, we propose effective heuristics. Under today's typical connection-bandwidth distribution where lower bandwidth connections outnumber higher bandwidth connections, we find the following: 1) it is beneficial to groom working paths and backup paths separately, as in PAL and SPAC; 2) separately protecting each individual connection, i.e., SPAC, yields the best performance when the number of grooming ports is sufficient; 3) protecting each specific lightpath, i.e., PAL, achieves the best performance when the number of grooming ports is moderate or small. 相似文献
15.
Chi-Chun Lo Bin-Wen Chuang 《Communications Magazine, IEEE》2003,41(3):146-152
For high-speed networks, a restoration mechanism based on backup path (BP) provides a means for assuring their survivability. We propose a two-phase BP reservation mechanism for high-speed networks. In the admission phase, a pair of working path (WP) and backup path is selected from the provisioned sets of WPs and BPs. In the adjustment phase, if backup capacity utilization exceeds the preset threshold, BP assignments are rearranged to optimize the usage of backup capacity. A mathematical model is formulated to verify the quality of the optimized solutions. Computational experiments indicate that the proposed mechanism significantly reduces the consumption of backup capacity while still maintaining a high degree of survivability. Moreover, experiments show that the optimized solutions obtained are on average within 3.6 percent of optimal. 相似文献
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18.
Der-Rong Din 《Photonic Network Communications》2009,18(1):1-13
In a Wavelength Division Multiplexing (WDM) network, the performance of the virtual topology (VT) designed for a pre-specified traffic pattern can be improved
by performing virtual topology reconfiguration (VTR). Simultaneously, the provision of survivability of WDM networks is important, because the transmission of huge data
should be protected when a fiber fails. Thus, the combination of survivability and reconfiguration is an important issue in
WDM networks. In this paper, the Virtual Topology Reconfiguration Problem (VTRP) in survivable WDM networks with a reconfiguration constraint is studied. Given the physical topology, dedicated path-protection VT, and a new traffic demand matrix, the goal of VTRP
is to reconfigure the current VT under the pre-specified reconfiguration constraint so that the objective value can be minimized.
The object cost of VTRP is the average weighted propagation delay (AWPD). Because designing a polynomial time algorithm to find the optimal solution of VTRP is impractical, in this paper,
a simulated annealing (SA) algorithm and a genetic algorithm (GA) are proposed to solve this problem. Experimental results of these algorithms are also given.
相似文献
Der-Rong DinEmail: Email: |
19.
Protected Working Capacity Envelope (PWCE) has been proposed to simplify resource management and traffic control for survivable
WDM networks. In a PWCE-based network, part of the link capacity is reserved for accommodating working routes, and the remaining
capacity is reserved for backup routes. The shortest path routing is applied in PWCE-based networks. An arrival call is accepted
only when each link along the shortest path has a free working channel. Such a working path routing scheme greatly simplifies
the call admission control process for dynamic traffic, and it is especially suitable for implementation in a distributed
manner among network nodes. In this article, we investigate two protection strategies: Bundle Protection (BP) and Individual
Protection (IDP). In BP, only one backup path can be used to protect a failure component, whereas multiple backup paths can
be used in IDP. We formulate four mixed integer non-linear programming (MINLP) problems using BP and IDP strategies for single
link and single node failure protection. Each model is designed to determine link metrics for shortest working path routing,
working and backup channel assignments, and backup path planning. Our objective is to minimize call-blocking probability on
the bottleneck link. Since these models are highly non-linear and non-convex, it is difficult to obtain exact global optimal
solutions. We propose a Simulated Annealing-based Heuristic (SAH) algorithm to obtain near optimal solutions. This SAH adopts
the concepts of simulated annealing as well as the bi-section technique to minimize call-blocking probabilities. To evaluate
the performance, we made simulation comparisons between SAH and the unity link weight assignment scheme. The results indicate
that SAH can greatly reduce call-blocking probabilities on benchmark and the randomly generated networks. 相似文献
20.
This paper proposes an optimal design scheme for survivable wavelength-division multiplexing (WDM) transport networks in which fast restoration can be achieved by using predetermined restoration paths that are independent of failure locations and which have one to one correspondence with working paths. Integer programming-based design problems are formulated to optimally determine working and their corresponding restoration paths, the number of fibers in each span, and the number of optical cross connects (OXCs) in each node. In these optimization problems, total facility cost, which includes not only transmission cost but also cross connection, is minimized. This design scheme can handle the dedicated/shared allocation of spare resources and several parameters, such as the maximum available number of wavelengths per fiber Ω, the matrix size of each OXC, and cross-connection to transmission cost-coefficient ratio γ. Total fiber length, the total number of OXCs, etc., are evaluated from obtained design results for these options and parameters. Numerical examples show that the dependency of total fiber length and the total number of OXCs on γ is relatively small, and cross-connection to transmission cost ratios (γ times the total number of OXCs divided by total fiber length) in the dedicated and shared cases are almost the same for each combination of γ and Ω 相似文献