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Grooming Multicast Traffic in Unidirectional SONET/WDM Rings
"... Abstract — In this paper we study the problem of efficient grooming of given nonuniform multicast traffic demands on a unidirectional SONET/WDM ring. The goal is to try to minimize the network cost as given by (i) the number of wavelengths required per fiber and (ii) the number of electronic AddDr ..."
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Abstract — In this paper we study the problem of efficient grooming of given nonuniform multicast traffic demands on a unidirectional SONET/WDM ring. The goal is to try to minimize the network cost as given by (i) the number of wavelengths required per fiber and (ii) the number of electronic AddDrop Multiplexers (ADMs) required on the ring. The problem is NP hard for both the cost functions. We observe that the problem with cost function (i) can be reduced to a corresponding traffic grooming problem for unicast traffic which can then be modelled as a standard circulararc graph coloring problem. For cost function (ii), we construct a graph based heuristic and compare it against the multicast extension of the best known unicast traffic grooming heuristic [1]. We observe that our heuristic requires fewer ADMs than required by the multicast extension of the unicast heuristic given in [1]. We also develop a lower bound and compare it against some upper bounds to study the maximum penalty of not employing intelligent wavelength assignment and/or traffic grooming under the unidirectional SONET/WDM ring scenario. Index Terms — Graph theory, SONET ring, traffic grooming, wavelength division multiplexing (WDM).
Grooming of multicast sessions in WDM ring networks
 in Proc. SPIE Opticomm
, 2003
"... In this paper, we address the problem of routing and wavelength assignment of multicast sessions with subwavelength traffic demands. We consider this problem in the scenario of WDM ring networks. In order to support multicasting, individual nodes need to have the capability to duplicate traffic. We ..."
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In this paper, we address the problem of routing and wavelength assignment of multicast sessions with subwavelength traffic demands. We consider this problem in the scenario of WDM ring networks. In order to support multicasting, individual nodes need to have the capability to duplicate traffic. We consider two different node architectures which perform the duplication in optical and electronic domain, respectively. As traffic duplication at the electronic level is much more expensive than the optical alternative, we study the problem of assigning routes and wavelengths to the multicast sessions so as to minimize electronic copying. The solution to this problem can be divided into three phases 1. routing of multicast sessions, 2. construction of circles by grouping nonoverlapping arcs and 3. grouping these circles onto wavelengths. We propose a heuristic algorithm which implements the routing as well as circle construction phases simultaneously and then groups the circles. We present extensive simulation results to show that our approach leads to much lesser equipment cost than that obtained by routing each multicast session along its minimum spanning tree and then using the best known heuristic for circle construction. 1
Reconfiguration of Subwavelength Groomed Wavelength Routed Optical Networks.
, 2003
"... 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
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...
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.
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
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.
Optical Traffic Grooming Based on Network Availability
"... Abstract. As the bandwidth request for traffic streams grows excessively, traffic grooming on wavelengthdivision multiplexing (WDM) mesh networks becomes more important. In general it efficiently grooms lowcapacity requests onto highcapacity lightpath. Thus network throughput and cost is improved. ..."
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Abstract. As the bandwidth request for traffic streams grows excessively, traffic grooming on wavelengthdivision multiplexing (WDM) mesh networks becomes more important. In general it efficiently grooms lowcapacity requests onto highcapacity lightpath. Thus network throughput and cost is improved. Also it affects the recent development of WDM passive optical network(PON) and the future fiber to the home(FTTH). Our objective is to improve the network throughput while maintaining the similar level of network cost. In this paper, we propose Dynamic Ordering on Lightpath Assignment (DOLA) algorithm, in which an order of lightpath assignment is determined according to the network availability. The comprehensive computer simulation results show that our proposed algorithm is up to about 14 % superior to the wellknown previous work [11]. 1
Design of LightTree Based Optical InterDatacenter Networks
"... Abstract—Nowadays, people’s daily lives are increasingly dependent on Internet applications provided by cloud service providers that replicate their content among geographically distributed datacenters using interdatacenter wide area networks to meet performance and reliability requirements. This ..."
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Abstract—Nowadays, people’s daily lives are increasingly dependent on Internet applications provided by cloud service providers that replicate their content among geographically distributed datacenters using interdatacenter wide area networks to meet performance and reliability requirements. This paper provides means for efficient design of interdatacenter networks with static traffic scenarios, where unicast and multicast connection requests are known a priori along with their start and end times. Also, the optical channel setup/teardown time is given. Integer linear programming (ILP) formulations that consider lighttree and lightpath connections are developed to minimize the network resource consumption. Since solving ILP formulations is time consuming for large networks, we also propose efficient heuristic algorithms. We demonstrate by simulations an advantage in efficiency for a lighttree based heuristic algorithm over its lightpath counterpart. This is due to its ability to construct and extend lighttrees to groom more connections. Both heuristic algorithms perform very close to the corresponding ILP optimal results in the case of a small network. Index Terms—Integer linear programming (ILP); Interdatacenter network; Lighttree; Setup/teardown time.