An efficient resources allocation strategy for survivable WDM network under static lightpath demand (original) (raw)
Related papers
2005
This paper addresses the problem of survivable lightpath provisioning in wavelength-division-multiplexing (WDM) mesh networks, taking into consideration optical-layer protection and some realistic optical signal quality constraints. The investigated networks use sparsely placed optical-electrical-optical (O/E/O) modules for regeneration and wavelength conversion. Given a fixed network topology with a number of sparsely placed O/E/O modules and a set of connection requests, a pair of link-disjoint lightpaths is established for each connection. Due to physical impairments and wavelength continuity, both the working and protection lightpaths need to be regenerated at some intermediate nodes to overcome signal quality degradation and wavelength contention. In the present paper, resource-efficient provisioning solutions are achieved with the objective of maximizing resource sharing. The authors propose a resource-sharing scheme that supports three kinds of resource-sharing scenarios, including a conventional wavelength-link sharing scenario, which shares wavelength links between protection lightpaths, and two new scenarios, which share O/E/O modules between protection lightpaths and between working and protection lightpaths. An integer linear programming (ILP)-based solution approach is used to find optimal solutions. The authors also propose a local optimization heuristic approach and a tabu search heuristic approach to solve this problem for real-world, large mesh networks. Numerical results show that our solution approaches work well under a variety of network settings and achieves a high level of resource-sharing rates (over 60% for O/E/O modules and over 30% for wavelength links), which translate into great savings in network costs.
Energy-efficient lightpath provisioning in a static WDM network with dedicated path protection
… (ICTON), 2011 13th …, 2011
The interest in the energy consumption of communication networks has risen in the recent years. In an effort to tackle this problem, several approaches have been presented to reduce the power consumed by the entire network infrastructure, including optical transport. Most of the solutions studied and proposed in the literature, however, pay little or no attention to the power consumed to ensure the resiliency of the overall network.
On lightpath scheduling in service differentiated survivable WDM mesh networks
2008
Service differentiated survivable WDM mesh networks providing dedicated path protection and shared path protection are investigated under scheduled traffic. Scheduled routing with holding-time aware and unaware are studied for comparison. To tackle the service provisioning problem, an integer linear programming(ILP) formulation is presented for either situation to find the optimal service provisioning solution for a given set of traffic demands. Numerical results show that over 48% capacity savings are achieved when the holding-time knowledge is exploited.
Design of Static Resilient WDM Mesh Networks with Multiple Heuristic Criteria
2002
We present a heuristic method to optimize the capacity of a WDM mesh network assigning working and protection capacity to a set of static optical-connection requests under the linkdisjoint constraint. The method can be applied to networks supporting either dedicated or shared path-protection. Routing and fiber and wavelength assignment (RFWA) are jointly performed for all the lightpaths with the aim of minimizing the number of fibers in the network. The employment of multiple prioritized heuristic criteria and an efficient link disjoint paths search algorithm are proposed. With less computational effort, the proposed heuristic approach allows to obtain good suboptimal results compared to the exact integer-linear-programming optimization. After introducing our design approach, we discuss the optimization of particular case-study networks under various condition and compare the results.
Wavelength Routing and Assignment in a Survivable WDM Mesh Network
Operations Research, 2003
All-optical networks with wavelength division multiplexing (WDM) capabilities are prime candidates for future wide-area backbone networks. The simplified processing and management of these very high bandwidth networks make them very attractive. A procedure for designing low cost WDM networks is the subject of this investigation. In the literature, this design problem has been referred to as the routing and wavelength assignment problem. Our proposed solution involves a three-step process that results in a low-cost design to satisfy a set of static point-to-point demands. Our strategy simultaneously addresses the problem of routing working traffic, determining backup paths for single node or single link failures, and assigning wavelengths to both working and restoration paths. An integer linear program is presented that formally defines the routing and wavelength assignment problem (RWA) being solved along with a simple heuristic procedure. In an empirical analysis, the heuristic procedure successfully solved realistically sized test cases in under 30 seconds on a Compaq AlphaStation. CPLEX 6.6.0 using default settings required over 1,000 times longer to obtain only slightly better solutions than those obtained by our new heuristic procedure.
A Hybrid Algorithm for Dynamic Lightpath Protection in Survivable WDM Optical Networks
2005
Dynamic lightpath protection in survivable WDM networks requires finding a pair of diverse routes (i.e., a primary route and a backup route that are link-disjoint) that form a cycle upon the arrival of a new connection request. In this paper, we propose a novel hybrid algorithm for this problem based on a combination of the mobile agents technique and genetic algorithms (GA). By keeping a suitable number of mobile agents in the network to cooperatively explore the network states and continuously report diverse routes into the routing tables, our new hybrid algorithm can promptly determine the first population of cycles for a new request based on the routing table of its source node, without requiring the time consuming process associated with current GA-based lightpath protection schemes. We furthermore improve the performance of our algorithm by introducing a more advanced fitness function. Extensive simulation studies on the ns-2 network simulator show that our hybrid algorithm achieve a significantly lower blocking probability and a smaller execution time than the conventional survivable routing algorithms.
Computer Networks, 2005
Path protection requires finding a working path and a protection path that are link disjoint. In this paper, we consider two fundamental problems on dynamic lightpath protection in WDM mesh networks. In the first problem, we consider a network without wavelength converters; thus both the working lightpath and protection lightpath are subject to the wavelength continuity constraint. Existing polynomial time algorithms can be applied to find a pair of link-disjoint lightpaths on a single wavelength; however, such algorithms fail if the working and protection lightpaths are on two different wavelengths. In the second problem, we consider a network with full wavelength conversion; thus the wavelength continuity constraint does not apply. Yet a single factor can cause multiple fiber links to fail simultaneously. The problem becomes finding link-disjoint lightpaths that are also risk disjoint. We prove that both of the two problems are NP-complete. We develop ILP formulations and heuristic algorithms for the two NP-complete problems. Practical constraints such as service level agreement (SLA) and priority are also considered. Computer simulations are conducted to evaluate the performance of the heuristic algorithms.
IOSR Journal of Electronics and Communication Engineering, 2014
In this paper, establishing a light path setup in WDM network done by implementing an ant-based mechanism Ant Colony Optimization (ACO) algorithm used for providing survivable routing in WDM network. The major problem in survivable routing WDM network is routing wavelength and assignment (RWA) problem, It sets up light path by routing and assigning a wavelength to each connection such that no light path use the same wavelength on same link .Our study aims to develop an routing and optimize the light path setup for survivable routing based upon the bit transmission to which supports data transfer supports to run continuously thus it can provide dynamic path. By adopting a new routing table structure and keeping a number of mobile agents in the network to cooperatively explore the network states and continuously update the routing tables, our new ant algorithm can efficiently support the ants' foraging tasks of route selection and wavelength assignment in WDM networks. Each path in the network is assigned by feasibility value. This feasibility value is calculated by considering the metrics such as bandwidth availability, path length and number of free wavelengths. When an ant is launched in the network by its node, it moves towards random destination to gather information such as bandwidth availability, path length and free wavelengths in that path. The value of path load is dynamically updated by the mobile agents in the load table. Using NS-2 simulation we show that the proposed ant based routing achieves better channel utilization and throughput with reduced delay, when compared with the normal routing. Optimization of light path performance is measured by varying the CBR traffic sending rate and flows.
On-line survivable routing in WDM networks
2009
In WDM networks, survivable routing and wavelength assignment (SRWA) involves assigning link-disjoint primary and backup lightpaths. In the on-line SRWA problem, a sequence of requests arrive and each request is either accepted or rejected based only on the input sequence seen so far. For special networks, we establish on-line algorithms with constant and logarithmic competitive ratios. It is not possible to obtain good competitive ratios in general topologies. Hence, we propose heuristic schemes and evaluate their performance by way of simulations. The building blocks in these schemes are 2-approximation algorithms (MSA and ESA) that we establish for the minimum disruption link-disjoint paths (MDLDP) problem. These approximations require far less memory and computation time than the best-known exact solution of the MDLDP problem. We use these three algorithms as heuristics for the on-line SRWA problem for infinite and finite duration requests and we show that, in terms of on-line performance, our algorithms do as well as (even at times better than) the exact algorithm of the MDLDP problem. We also provide an exact ILP formulation to solve the infinite duration off-line SRWA problem.
Path Protection in WDM Networks with Quality of Transmission Limitations
2010 IEEE International Conference on Communications, 2010
We consider path protection in the routing and wavelength assignment (RWA) problem for impairment constrained WDM optical networks. The proposed multicost RWA algorithms select the primary and the backup lightpaths by accounting for physical layer impairments. The backup lightpath may either be activated (1+1 protection) or it may be reserved and not activated, with activation taking place when/if needed (1:1 protection). In case of 1:1 protection the period of time where the quality of its transmission (QoT) is valid, despite the possible establishment of future connections, should be preserved, so as to be used in case the primary lightpath fails. We show that, by using the multicost approach for solving the RWA with protection problem, great benefits can be achieved both in terms of the connection blocking rate and in terms of the validity period of the backup lightpath. Moreover the multicost approach, by providing a set of candidate lightpaths for each source destination pair, instead of a single one, offers ease and flexibility in selecting the primary and the backup lightpaths.