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Traffic grooming in an optical WDM mesh network
 IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS
, 2002
"... In wavelengthdivision multiplexing (WDM) optical networks, the bandwidth request of a traffic stream can be much lower than the capacity of a lightpath. Efficiently grooming lowspeed connections onto highcapacity lightpaths will improve the network throughput and reduce the network cost. In WDM/S ..."
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Cited by 108 (8 self)
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In wavelengthdivision multiplexing (WDM) optical networks, the bandwidth request of a traffic stream can be much lower than the capacity of a lightpath. Efficiently grooming lowspeed connections onto highcapacity lightpaths will improve the network throughput and reduce the network cost. In WDM/SONET ring networks, it has been shown in the optical network literature that by carefully grooming the lowspeed connection and using wavelengthdivision multiplexer (OADM) to perform the optical bypass at intermediate nodes, electronic ADMs can be saved and network cost will be reduced. In this study, we investigate the trafficgrooming problem in a WDMbased optical mesh topology network. Our objective is to improve the network throughput. We study the node architecture for a WDM mesh network with trafficgrooming capability. A mathematical formulation of the trafficgrooming problem is presented in this study and several fast heuristics are also proposed and evaluated.
Reducing electronic multiplexing costs in SONET/WDM rings with dynamically changing traffic
 IEEE Journal on Selected Areas in Communications
, 2000
"... In this paper we consider traffic grooming in WDM/SONET ring networks when the offered traffic is characterized by a set of traffic matrices. Our objective is to minimize the cost of electronic Add/Drop Multiplexers (ADMs) in the network, while being able to support any offered traffic matrix in a r ..."
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Cited by 36 (3 self)
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In this paper we consider traffic grooming in WDM/SONET ring networks when the offered traffic is characterized by a set of traffic matrices. Our objective is to minimize the cost of electronic Add/Drop Multiplexers (ADMs) in the network, while being able to support any offered traffic matrix in a rearrangeably nonblocking manner. We provide several methods for reducing the required number of ADMs for an arbitrary class of traffic matrices. We then consider the special case where the only restriction on the offered traffic is a constraint on the number of circuits a node may source at any given time. For this case, we provide a lower bound on the number of ADMs required and give conditions that a network must satisfy in order for it to support the desired set of traffic patterns. Circuit assignment and ADM placement algorithms with performance close to this lower bound are provided. These algorithms are shown to reduce the electronic costs of a network by up to 27%. Finally, we discuss extensions of this work for supporting dynamic traffic in a widesense or strict sense nonblocking manner as well as the benefits of using a hub node and tunable transceivers. Much of this work relies on showing that these grooming problems can often be formulated as standard combinatorial optimization problems.
Algorithm for Traffic Grooming in Optical Networks to Minimize the Number of Transceivers
 Major Indices for the Hyperoctahedral Group, Manuscript
, 2001
"... In this paper, we study the problem of traffic grooming to reduce the number of transceivers in optical networks. We show that this problem is equivalent to a certain traffic maximization problem. We give an intuitive interpretation of this equivalence and use this interpretation to derive a greedy ..."
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Cited by 33 (0 self)
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In this paper, we study the problem of traffic grooming to reduce the number of transceivers in optical networks. We show that this problem is equivalent to a certain traffic maximization problem. We give an intuitive interpretation of this equivalence and use this interpretation to derive a greedy algorithm for transceiver minimization. We discuss implementation issues and present computational results comparing the heuristic solutions with the optimal solutions for several small example networks. For larger networks, the heuristic solutions are compared with known bounds on the optimal solution obtained using integer programming tools.
A Comprehensive Study on Nextgeneration Optical Grooming Switches
 IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS
, 2003
"... This paper investigates the characteristics and performance of different optical grooming switches, i.e., optical crossconnects (OXCs) capable of traffic grooming, under a dynamic traffic environment. We present four optical groomingOXC architectures, namely, singlehop grooming OXC, multihop par ..."
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Cited by 26 (4 self)
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This paper investigates the characteristics and performance of different optical grooming switches, i.e., optical crossconnects (OXCs) capable of traffic grooming, under a dynamic traffic environment. We present four optical groomingOXC architectures, namely, singlehop grooming OXC, multihop partialgrooming OXC, multihop fullgrooming OXC, and lighttreebased sourcenode grooming OXC. After exploring their grooming capabilities, we propose three grooming schemes and two corresponding algorithms, grooming using auxiliary graph and grooming using lighttree. Through the algorithms, we evaluate the performance of different optical grooming OXCs in a dynamic traffic environment under different connection bandwidthgranularity distributions. Our investigation uncovers the following results: 1) the multihop fullgrooming OXC can achieve the best network performance, but it may encounter cost and scalability constraints; 2) by using significantly less lowgranularity electronic processing and intelligent trafficgrooming algorithms, the multihop partialgrooming OXC shows reasonable network performance and, hence, can be viewed as a costeffective alternative when a network node does not require fullgrooming capability; 3) the singlehop grooming OXC may cause a large amount of capacity waste and lead to poor network performance; and 4) through its multicast capability, a lighttreebased sourcenode grooming OXC can significantly outperform the performance of a singlehop grooming OXC in terms of network throughput and network resource efficiency. From our results, we also observe that the connection bandwidthgranularity distribution has a large impact on network throughput and network resource efficiency and, therefore, should be carefully considered for network design and traffic provisioning.
P.J.: Traffic partition in WDM/SONET rings to minimize SONET ADMs
 J. Comb. Optim
, 2002
"... ..."
A link bundled auxiliary graph model for constrained dynamic traffic grooming in WDM mesh networks
 IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS
, 2005
"... This paper addresses the twolayer dynamic traffic grooming problem in wavelengthdivisionmultiplexed (WDM) mesh optical networks subject to resource constraints and the generalized wavelength continuity (GWC) constraint. The GWC constraint is a relaxed wavelength continuity constraint which incor ..."
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Cited by 5 (2 self)
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This paper addresses the twolayer dynamic traffic grooming problem in wavelengthdivisionmultiplexed (WDM) mesh optical networks subject to resource constraints and the generalized wavelength continuity (GWC) constraint. The GWC constraint is a relaxed wavelength continuity constraint which incorporates various kinds of wavelength conversion capabilities that exist in optical networks. As an improvement over the existing layered auxiliary graph (layeredAG) approach which represents each wavelength separately in the auxiliary graph, we introduce a largely simplified link bundled auxiliary graph (LBAG) model and propose the SAGLB method to find paths and assign wavelengths for new lightpaths subject to the GWC constraint. We propose the constrained integrated grooming algorithm (CIGA) based on the LBAG model. A grooming policy influences the resource utilization by determining the weight function of the auxiliary graph. We propose the least resource path first (LR) grooming policy, which is an improvement over the existing grooming policies in the literature, by integrating the wavelength and transceiver metrics together. Simulation results show that the LBAG model achieves a comparable blocking performance with the layeredAG approach while using a significantly less amount of running time. We also present the worst case time complexity analysis of the CIGA grooming algorithm and evaluate the performance of the LR grooming policy by simulation.
The role of switching in reducing the number of electronic ports in WDM networks
 IEEE J. Select. Areas Commun
, 2004
"... Abstract—We consider the role of switching in minimizing the number of electronic ports [e.g., synchronous optical network (SONET) add/drop multiplexers] in an optical network that carries subwavelength traffic. Providing nodes with the ability to switch traffic between wavelengths, such as through ..."
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Cited by 2 (0 self)
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Abstract—We consider the role of switching in minimizing the number of electronic ports [e.g., synchronous optical network (SONET) add/drop multiplexers] in an optical network that carries subwavelength traffic. Providing nodes with the ability to switch traffic between wavelengths, such as through the use of SONET crossconnects, can reduce the required number of electronic ports. We show that only limited switching ability is needed for significant reductions in the number of ports. First, we consider architectures where certain “hub ” nodes can switch traffic between wavelengths and other nodes have no switching capability. For such architectures, we provide a lower bound on the number of electronic ports that is a function of the number of hub nodes. We show that our lower bound is relatively tight by providing routing and grooming algorithms that nearly achieve the bound. For uniform traffic, we show that the number of electronic ports is nearly minimized when the number of hub nodes used is equal to the number of wavelengths of traffic generated by each node. Next, we consider architectures where the switching ability is distributed throughout the network. Such architectures are shown to require a similar number of ports as the hub architectures, but with a significantly smaller “switching cost. ” We give an algorithm for designing such architectures and characterize a class of topologies, where the minimum number of ports is used. Finally, we provide a general upper bound on the amount of switching required in the network. For uniform traffic, our bound shows that as the size of the network increases, each traffic stream must be switched at most once in order to achieve the minimum port count. Index Terms—Optical networks, synchronous optical network (SONET), traffic grooming. I.
Optical WDM Networks: Traffic Grooming in Mesh Networks and Metro Networks using ROADMs
, 2005
"... Optical Fiber technology employing wavelengthdivision multiplexing (WDM) has and continues to be investigated and commercially deployed to meet our everincreasing bandwidth demands. WDM partitions the huge bandwidth of an optical fiber into many nonoverlapping wavelength channels, each of which c ..."
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Optical Fiber technology employing wavelengthdivision multiplexing (WDM) has and continues to be investigated and commercially deployed to meet our everincreasing bandwidth demands. WDM partitions the huge bandwidth of an optical fiber into many nonoverlapping wavelength channels, each of which can operate at the data rate of 10 Gbps (or 40 Gbps or higher). This dissertation investigates design and modeling issues of optical WDM mesh networks, as well as ring networks. This dissertation first proposes a novel generic graph model for traffic grooming in heterogeneous WDM mesh networks so that lowspeed traffic streams can be “groomed ” (or carried) by highcapacity wavelength channels. This model uses an auxiliary graph to represent the network state, which can accommodate various resource constraints. It can achieve different grooming policies by employing a simple shortestpath algorithm, and it can be applied to both static and dynamic trafficgrooming scenarios. A grooming policy determines how to carry the traffic in a certain situation.
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.
Optical Networks with Hybrid Routing
, 2003
"... Alloptical switching or wavelength routing has the benefit of optical bypass that can eliminate expensive high speed electronic processing at intermediate nodes and reduce significantly the cost of high bandwidth transport. But alloptical switching has the limitations of coarse granularity, lack o ..."
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Alloptical switching or wavelength routing has the benefit of optical bypass that can eliminate expensive high speed electronic processing at intermediate nodes and reduce significantly the cost of high bandwidth transport. But alloptical switching has the limitations of coarse granularity, lack of multiplexing gain, and scarcity of wavelength resources, which do not mesh well with Internet traffic that has many small and diverse flows and emphasizes the importance of resource sharing. In particular, wavelength routed light paths have difficulty to seamlessly converge with MPLS labelswitched paths that have arbitrary bandwidth granularity and relatively abundant labels. In this paper, we propose a hybrid wavelength and subwavelength routing scheme that can preserve the benefits of optical bypass for large traffic flows at the same time provide multiplexing gain for small traffic flows. We first study the hybrid routing scheme using static optimization that produces an optimal path set and a partition between wavelength and subwavelength routing. We then present a dynamic heuristic that tracks the static optimization closely. During the process, we proposed a traffic arrival process called incremental arrival with sporadic random termination to more accurately model practical optical network traffic generation process.