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Bounds on Traffic Grooming in Star and Tree Networks
, 2001
"... We consider the problem of grooming traffic in WDM star and tree networks to minimize equipment cost. We prove an important result regarding wavelength assignment in both topologies. We present a series of lower and upper bounds on the optimal solutions for both star and tree networks. The bounds al ..."
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We consider the problem of grooming traffic in WDM star and tree networks to minimize equipment cost. We prove an important result regarding wavelength assignment in both topologies. We present a series of lower and upper bounds on the optimal solutions for both star and tree networks. The bounds allow us to evaluate a set of heuristics we also develop.
A Sequence of Bounds for the Problem of Minimizing Electronic Routing in Wavelength Routed Optical Rings
, 2000
"... We consider the problem of designing a virtual topology to minimize electronic routing in wavelength routed optical rings. The full virtual topology design problem is NPhard even in the restricted case where the physical topology is a ring, and various heuristics have been proposed in the literatur ..."
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We consider the problem of designing a virtual topology to minimize electronic routing in wavelength routed optical rings. The full virtual topology design problem is NPhard even in the restricted case where the physical topology is a ring, and various heuristics have been proposed in the literature for obtaining good solutions, usually for different classes of problem instances. We present a new framework which can be used to evaluate the performance of heuristics, and which requires significantly less computation than evaluating the optimal solution. This framework is based on a general formulation of the virtual topology problem, and it consists of a sequence of bounds, both upper and lower, in which each successive bound is at least as strong as the previous one. The successive bounds take larger amounts of computation to evaluate, and the number of bounds to be evaluated for a given problem instance is only limited by the computational power available. The bounds are based...
GROOMING IN WDM NETWORKS
, 2001
"... Wavelength division multiplexing (WDM) in optical fiber networks is widely viewed as the technology with the potential to satisfy the everincreasing bandwidth needs of network users effectively and on a sustained basis. In WDM networks, nodes are equipped with optical crossconnects (OXCs), devices ..."
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Wavelength division multiplexing (WDM) in optical fiber networks is widely viewed as the technology with the potential to satisfy the everincreasing bandwidth needs of network users effectively and on a sustained basis. In WDM networks, nodes are equipped with optical crossconnects (OXCs), devices which can optically switch a signal on any given wavelength from any input port to any output port. This makes it possible to establish lightpaths between any pair of network nodes. A lightpath is a clear channel in which the signal remains in optical form throughout the physical path between the two end nodes. The set of lightpaths established over the fiber links defines a virtual topology. Consequently, the problem arises of designing virtual topologies to optimize a performance measure of interest for a set of traffic demands. With the deployment of commercial WDM systems, it has become apparent that the cost of network components, especially line terminating equipment (LTE) is the dominant cost in building optical networks, and is a more meaningful metric to optimize than, say, the number of wavelengths. Furthermore, since the data rates at which each individual wavelength operates continue to increase (to OC192 and beyond), it becomes clear that a number of independent traffic components must be multiplexed in order to efficiently utilize the wavelength capacity. These observations give rise to the concept of traffic grooming, which refers to the techniques used to combine lower speed components onto available wavelengths in order to meet network design goals such as cost minimization. Traffic grooming is a hard problem in general which remains computationally intractable even for simple networks. We consider the problem of traffic grooming in ring, star and tree topologies. We provide theoretical results regarding achievability bounds for these networks as well as practical frameworks to obtain increasingly better feasible solutions with the expenditure of more computational power. VIRTUAL TOPOLOGY DESIGN FOR TRAFFIC
ABSTRACT SRINIVASARAO, KOUNDINYA B. Traffic Grooming in Translucent Optical Ring Net
"... works. (Under the direction of Dr. Rudra Dutta). The exponential growth of the Internet has resulted in an ever increasing demand for bandwidth. Carrier networks which form the backbone of the Internet, have been designed to carry only voice signals with predictable traffic patterns and anticipatin ..."
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works. (Under the direction of Dr. Rudra Dutta). The exponential growth of the Internet has resulted in an ever increasing demand for bandwidth. Carrier networks which form the backbone of the Internet, have been designed to carry only voice signals with predictable traffic patterns and anticipating slow growth of the network. With the advances in fiber optics and wavelength division multiplexing (WDM) optical networking is the key to satisfy the datadriven bandwidth demand. These technologies enable simultaneous transmission of signals on separate highspeed channels at different wavelengths. While the bandwidth provided by these channels is very high, individual traffic demands are at the subwavelength level. This mismatch can be overcome by multiplexing several lower rate connections onto the highspeed channels in a costeffective manner. This technique is referred to as traffic grooming. Traffic grooming in WDM networks has been a widely addressed problem in recent years. Traffic grooming and its constituent subproblems have been proven to be NPcomplete for even the most elemental of network topologies. The ring topology has been the target of a large number of the studies because of its practical relevance. However, most existing studies concentrate
The Impact of the Number of Add/drop Ports in Wavelength Routing AllOptical Networks
, 2003
"... The study of wavelengthrouting optical networks is an exciting research topic that has been attracting a lot of attention recently. For the design and operation of these networks, it would be important to study the way network performance is affected by factors such as wavelength number, wavel ..."
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The study of wavelengthrouting optical networks is an exciting research topic that has been attracting a lot of attention recently. For the design and operation of these networks, it would be important to study the way network performance is affected by factors such as wavelength number, wavelength conversion capability and the number of usable add/drop ports at the optical switches. We study the performance of wavelengthrouting alloptical networks with both limited number of link capacities (i.e.
Mechanisms for Procviding Optical Bypass in WDMBased Networks
 Optical Networks
, 2000
"... The recent emergence of Wavelength Division Multiplexing (WDM) technology has led to a tremendous increase in the available transmission capacity in widearea networks. Consequently, these networks may no longer be limited by transmission bandwidth, but rather by the processing capability of el ..."
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The recent emergence of Wavelength Division Multiplexing (WDM) technology has led to a tremendous increase in the available transmission capacity in widearea networks. Consequently, these networks may no longer be limited by transmission bandwidth, but rather by the processing capability of electronic switches, routers and multiplexers in the network.This realization has led to a new wave of research aimed at overcoming the electronic bottleneck by providing optical bypass at the WDM layer. In this paper we survey some of the recent work in this area, including mechanisms for providing optical bypass in both circuit and packet switched networks.We pay particular attention to techniques that take advantage of configurable WDM technology to dynamically reconfigure the electronic topology of the network in response to changes in traffic conditions. We show that for both circuit and packet switched traffic, having a configurable WDM topology can lead to a significant incr...
MingHsiung, Chiayi
"... s Abstract: This paper considers the scheduling problem of packet transmissions in a TDM/WDM unidirectional optical ring network. Our objective is to design a scheduling scheme for packet transmission with minimum scheduling length satisfying a set of traffic requirements. We focus on a fairly gener ..."
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s Abstract: This paper considers the scheduling problem of packet transmissions in a TDM/WDM unidirectional optical ring network. Our objective is to design a scheduling scheme for packet transmission with minimum scheduling length satisfying a set of traffic requirements. We focus on a fairly general case in that nonuniform traffic demands and arbitrary transmitter tuning latencies are allowed. Since the scheduling problem in TDM/WDM ring networks is known to be NPComplete, we formulate the problem as an Integer Linear Program (ILP) and propose some heuristic algorithms to find feasible solutions.
ONETOALL PERSONALIZED COMMUNICATION IN TORUS NETWORKS
"... Given a multicomputer system of parallel processors connected in a torus network, the onetoall personalized communication is to send from the root processor unique data to each of the other processors in the network. Under the assumptions of samesize data to each processor, storeandforward routi ..."
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Given a multicomputer system of parallel processors connected in a torus network, the onetoall personalized communication is to send from the root processor unique data to each of the other processors in the network. Under the assumptions of samesize data to each processor, storeandforward routing, and allport processors, we formulate the onetoall personalized communication problem as an optimization problem with the goal to minimize the total elapsed time (measured in the number of time steps) for all data to reach their respective destinations. We design an optimal algorithm based on partitioning the torus network into disjoint subnetworks. We also present a heuristic algorithm based on a greedy strategy. We implement the algorithms on two Linux clusters with Gigabit Ethernet torus connection, currently in use at the Jefferson National Lab and configured as a 2dimensional 8 × 8 torus and a 3dimensional 4 × 8 × 8 torus, respectively. We analyze the performance of the algorithms using data collected in experiments. KEY WORDS Onetoall personalized communication, scatter and gather, parallel computing, torus network, algorithm, optimization. 1
ABSTRACT Mahalati, Ruhiyyih Reconfiguration of Subwavelength Groomed Wavelength Routed Optical Networks.
"... Telecommunication networks recently have seen a large increase in traffic demands, especially data traffic as compared to voice traffic. With the advances in fiber optics and wavelength division multiplexing (WDM) optical networking is the key to satisfy the datadriven bandwidth demand. These techn ..."
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Telecommunication networks recently have seen a large increase in traffic demands, especially data traffic as compared to voice traffic. With the advances in fiber optics and wavelength division multiplexing (WDM) optical networking is the key to satisfy the datadriven bandwidth demand. These technologies enable simultaneous transmission of signals on separate highspeed channels at different wavelengths. While current technologies can provide such huge bandwidth, in order to utilize efficiently the capacity of each lightpath, a number of independent lowerrate traffic streams must be multiplexed into a single lightpath. This technique is referred to as traffic grooming. Another most attractive feature of WDM and wavelength routing networks is the possibility of adaptively creating virtual topologies, or a set of lightpaths, based on network need, giving rise to the concept of reconfiguration. Till date, however, there has been little or no work on the joint consideration of the two areas of traffic grooming and reconfiguration, even though it is clear that reconfiguration is at least equally important in the realistic networks of tomorrow which will definitely need to carry subwavelength traffic. This is probably due to two reasons: the common wisdom has been that the two aspects can be handled separately, and also it is hard to define reasonable network design goals if the two aspects are considered jointly. In this thesis, we examine this issue
A PRACTICAL AND COSTEFFECTIVE APPROACH TO EFFICIENT TRAFFIC GROOMING IN WDM MESH NETWORKS ∗
"... In this chapter, we present a new scheme for traffic grooming in WDM mesh networks. We put forward a new node architecture which brings together all the three qualities desired 1. practical feasibility, 2. costeffectiveness and 3. efficient grooming capability. None of the models considered so far ..."
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In this chapter, we present a new scheme for traffic grooming in WDM mesh networks. We put forward a new node architecture which brings together all the three qualities desired 1. practical feasibility, 2. costeffectiveness and 3. efficient grooming capability. None of the models considered so far in the literature have managed to satisfy all three criteria. We achieve these three ideals by considering a combination of groomers at multiple traffic granularities. We also present an algorithm for efficient traffic grooming with this new architecture. We justify the need for this new algorithm by imposing our node architecture on existing algorithms and comparing with them through a wide range of simulations.