Dynamic routing in translucent WDM optical networks

Yang, Xi; Ramamurthy, Byrav

doi:10.1109/icc.2002.997352

Cited by 46 publications

(37 citation statements)

References 11 publications

(10 reference statements)

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“…If a connection traverses several islands, the island boundary nodes carry out the signal regeneration. The same idea has been employed in some recent works such as [10]. The problem of this approach is its low scalability.…”

Section: Related Workmentioning

confidence: 99%

Offline Impairment-Aware RWA and Regenerator Placement in Translucent Optical Networks

Garcia-Manrubia

Pavón‐Mariño

Aparicio-Pardo

et al. 2011

J. Lightwave Technol.

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Abstract-In translucent optical networks the physical layer impairments degrading the optical signal are considered in the network design. In this paper we investigate the offline problem of Routing and Wavelength Assignment (RWA) and Regenerator Placement (RP) in translucent networks. Given a network topology, an estimation of the traffic demands, the objective is to minimize the cost of the regeneration equipment used, and to avoid the lightpath blocking. We formulate an optimal ILP model of the problem, to the best of the authors' knowledge, for the first time in the literature. Its simplicity allows us to test it for small and medium size networks. Despite of this merit, the problem is NP-hard. For larger problem instances we propose two heuristic methods: Lightpath Segmentation and 3-Step method. The latter guarantees that no lightpath blocking is produced by signal degradation. We also provide a lower bound for the regenerator equipment cost. The performance and the scalability of our proposals are then investigated by carrying out extensive tests, considering different network topologies, number of wavelengths per fiber, traffic load conditions and network link lengths. Results reveal that the solutions obtained by the heuristic algorithms are optimal or close-to-optimal and require low computation times. In addition, the results help to capture the trends in the regenerator equipment cost in different network instances.

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Section: Related Workmentioning

confidence: 99%

Offline Impairment-Aware RWA and Regenerator Placement in Translucent Optical Networks

Garcia-Manrubia

Pavón‐Mariño

Aparicio-Pardo

et al. 2011

J. Lightwave Technol.

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“…An alternative to sparse placement was proposed in [5,9,10], where it was pointed out that regenerators can share transceivers in access stations in all nodes. Since it is unlikely that lightpaths which are initiated and terminated at a node will use up all the Tx/Rx pairs in the access stations, many nodes will have spare Tx/Rx pairs available for regeneration.…”

Section: Introductionmentioning

confidence: 99%

Distributed Dijkstra sparse placement routing algorithm for translucent optical networks

Tintor

Radunovic

2008

Photon Netw Commun

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In this paper we study translucent optical networks as an alternative to fully transparent and fully opaque optical networks. In the former networks, a technique called sparse placement is used to overcome the lightpath blocking caused by the signal quality degradation, using much less regenerators, which must strategically be placed, in contrast to a fully opaque network. In this paper we propose a sparse placement algorithm based on two requirements. The first one is signal regeneration necessary to re-amplify, reshape, and retime the optical signals after some predefined transparent distance in order to successfully receive the signals at the destination node. The other is load balance of the traffic in the network aimed at efficient usage of the network capacity resources. We apply a distributed Dijkstra routing algorithm which dynamically changes weights of links during the process of locating regeneration capable nodes. We compare the performance of the proposed algorithm with commonly used sparse placement algorithms through simulation experiments. The benefits are such that load balancing of the network traffic is fully utilized, and with technological development it will be sufficient to equip up to 30% of nodes in the network with electronic regenerations in order to have the same performance as in an opaque network.

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“…The problem of placing regenerators in optical networks has attracted the attention of several recent research works [5,8,9,13,18,19,22,23]. Mostly, these articles propose heuristics and run simulations in order to reduce the number of regenerators, but no theoretical analysis is presented.…”

Section: Introductionmentioning

confidence: 99%

Placing Regenerators in Optical Networks to Satisfy Multiple Sets of Requests

Mertzios

Shalom

et al. 2010

Automata, Languages and Programming

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Abstract. The placement of regenerators in optical networks has become an active area of research during the last years. Given a set of lightpaths in a network G and a positive integer d, regenerators must be placed in such a way that in any lightpath there are no more than d hops without meeting a regenerator. While most of the research has focused on heuristics and simulations, the first theoretical study of the problem has been recently provided in [10], where the considered cost function is the number of locations in the network hosting regenerators. Nevertheless, in many situations a more accurate estimation of the real cost of the network is given by the total number of regenerators placed at the nodes, and this is the cost function we consider. Furthermore, in our model we assume that we are given a finite set of p possible traffic patterns (each given by a set of lightpaths), and our objective is to place the minimum number of regenerators at the nodes so that each of the traffic patterns is satisfied. While this problem can be easily solved when d = 1 or p = 1, we prove that for any fixed d, p ≥ 2 it does not admit a PTAS, even if G has maximum degree at most 3 and the lightpaths have length O(d). We complement this hardness result with a constant-factor approximation algorithm with ratio ln(d · p). We then study the case where G is a path, proving that the problem is NP-hard for any d, p ≥ 2, even if there are two edges of the path such that any lightpath uses at least one of them. Interestingly, we show that the problem is polynomial-time solvable in paths when all the lightpaths share the first edge of the path, as well as when the number of lightpaths sharing an edge is bounded. Finally, we generalize our model in two natural directions, which allows us to capture the model of [10] as a particular case, and we settle some questions that were left open in [10].

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Dynamic routing in translucent WDM optical networks

Cited by 46 publications

References 11 publications

Offline Impairment-Aware RWA and Regenerator Placement in Translucent Optical Networks

Offline Impairment-Aware RWA and Regenerator Placement in Translucent Optical Networks

Distributed Dijkstra sparse placement routing algorithm for translucent optical networks

Placing Regenerators in Optical Networks to Satisfy Multiple Sets of Requests

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