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Selected Areas in Communications, IEEE Journal on

Issue 8 • Date Aug. 2006

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Displaying Results 1 - 12 of 12
  • IEEE Journal on Selected Areas in Communications : Supplement on optical communications & networking

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  • Heuristic algorithms for the routing and wavelength assignment of scheduled lightpath demands in optical networks

    Page(s): 2 - 15
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    This paper addresses the problem of routing and wavelength assignment (RWA) of scheduled lightpath demands (SLDs) in wavelength routed optical networks with no wavelength converters. The objective is to minimize the number of wavelengths used. This problem has been shown to be NP-complete so heuristic algorithms have been developed to solve it suboptimally. Suggested is a tabu search algorithm along with two simple and fast greedy algorithms for the RWA SLD problem. We compare the proposed algorithms with an existing tabu search algorithm for the same problem and with lower bounds derived in this paper. Results indicate that the suggested algorithms not only yield solutions superior in quality to those obtained by the existing algorithm, but have drastically shorter execution times View full abstract»

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  • Efficient multi-layer operational strategies for survivable IP-over-WDM networks

    Page(s): 16 - 31
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (701 KB) |  | HTML iconHTML  

    This paper addresses the problem of achieving a balance in satisfying a network service provider's requirements: maintaining an acceptable call acceptance rate, satisfying protection requirements of requests, and controlling the signaling overhead in case of a component failure, in IP-over-WDM networks in a dynamic traffic arrival scenario. Satisfying all these aspects is a difficult task especially when the traffic pattern is dynamic in nature and a single layer protection approach is followed. In this work, first we propose a multi-layer protection scheme for achieving a better and acceptable tradeoff between blocking performance and signaling overhead in IP-over-WDM networks. We define various operational settings in the proposed scheme and investigate their impacts on the performance of the scheme. An important feature of this scheme is that, these settings allow a network service provider to select a suitable operational strategy for achieving the desired tradeoff based on network's policy and traffic demand. Then we propose an adaptive protection approach for dynamic traffic in consideration of providing better protection to requests as much as possible while considering blocking performance and signaling overhead. Through simulation experiments we evaluate the performance of the proposals and demonstrate their effectiveness View full abstract»

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  • Fair sharing using dual service-level agreements to achieve open access in a passive optical network

    Page(s): 32 - 44
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1250 KB) |  | HTML iconHTML  

    The Passive Optical Network (PON) is an attractive solution for high-bandwidth access networks. In the context of a broadband access network, the term open access implies the ability of multiple service providers to share the deployed access network infrastructure to make services available to the end users. Multiple services may thereby be delivered over a shared access channel. Open access requires fairness in terms of throughput, delay, jitter, and other network parameters in the access channel among the sharing entities, namely service providers and end users. Since the traffic in an access network is very bursty, an access network may be frequently subjected to high loads for certain durations of time. Meeting the above fairness requirements under such conditions is therefore very challenging. In this study, we first motivate the problem of meeting fairness requirements simultaneously to both service providers and users, which are located at opposite ends of an access channel. We then investigate the importance of two different sets of Service-Level Agreements (SLAs), which we call Dual SLAs. After formulating a mathematical model, we propose an efficient scheduling algorithm to meet Dual SLAs which is based on the well-known concept of max-min fairness. We then demonstrate the effectiveness of our proposed algorithm through simulations using a discrete-event-simulator-based PON set-up, which compares the fairness of the Dual-SLA scheduling algorithm with that of other traditional fair queuing algorithms such as Deficit Round Robin (DRR) View full abstract»

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  • An improved algorithm for optimal lightpath establishment on a tree topology

    Page(s): 45 - 56
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (351 KB) |  | HTML iconHTML  

    Routing and wavelength assignment (RWA) aims to assign the limited number of wavelengths in a wavelength-division multiplexed (WDM) optical network so as to achieve greater capacity. In a recent paper, Datta et al. studied the problem of establishing a set of disjoint lightpaths on a tree topology using a single wavelength to maximize the total traffic supported by the chosen set of lightpaths. They discussed applications of this problem to RWA and presented a dynamic programming algorithm which optimally solves this problem in Oscr(n4+nDscr3) time, where n is the number of nodes in the network and Dscr is the maximum node degree. In this paper, we present an improved algorithm with a time complexity of Oscr(n2+nDscr2) View full abstract»

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  • Backup reprovisioning to remedy the effect of multiple link failures in WDM mesh networks

    Page(s): 57 - 67
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (559 KB) |  | HTML iconHTML  

    As networks grow in size and complexity, both the probability and the impact of failures increase. The pre-allocated backup bandwidth, which has been widely investigated in the literature, may not be able to provide full protection guarantee when multiple failures occur in a network. In this study, we consider multiple concurrent failures where concurrent means that a new failure occurs before a previous failure is repaired. To combat the effect of multiple concurrent failures, new backups can be reprovisioned after one failure such that the next potential failure can be handled effectively and efficiently. We consider dynamic traffic where a pair of link-disjoint primary and backup paths is provisioned when a new connection request arrives. After a failure occurs, the affected connections switch traffic from their primary paths to backup paths. To protect against next potential failure, we reprovision new backups for connections that become unprotected or vulnerable because of losing their primary or their backup due to the previous failure or due to backup resource sharing. This approach is called Minimal Backup Reprovisioning (MBR). An alternative approach is to globally rearrange backups for all connections after one failure occurs, which is called Global Backup Reprovisioning (GBR). Backup reprovisioning can be performed whenever the network's state changes, e.g., (1) when a new request arrives, (2) when an existing connection terminates, (3) when a network failure occurs, (4) when a failed link/node is repaired, etc., to utilize the available resources more efficiently or to recover quickly from the next failure. In this study, we perform MBR or GBR after one network failure occurs to protect against the next potential failure in a wavelength-convertible WDM mesh network. The link-vector network model which can maximally explore the backup-sharing potential is assumed in this study. We then analyze the complexity of MBR and GBR under such a network model. A r- - eprovisioning algorithm is proposed for MBR which can significantly reduce the connection vulnerability without the knowledge of the location of the next failure. In GBR, both integer linear program (ILP) and heuristic-based approaches are proposed. We compare capacity requirement and computational complexity of MBR to that of GBR through numerical examples. MBR demonstrates a good tradeoff between complexity and capacity efficiency to handle multiple concurrent failures View full abstract»

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  • Many-to-one traffic grooming with aggregation in WDM networks

    Page(s): 68 - 81
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    Most of the network applications bandwidth requirements are far less than the bandwidth offered by a full wavelength in WDM networks. Hence, traffic grooming is needed to make efficient use of the available resources. In this paper we address the grooming of many-to-one traffic demands in WDM networks on arbitrary topologies. Traffic streams from different sources, but part of the same session and thus terminating at the same destination, can be aggregated using arbitrary, but application dependent, aggregation ratios. We provide optimal as well as heuristic solutions to the problem. The objective is to minimize the cost of the network, by minimizing the total number of the higher layer components and the total number of the wavelengths used in the network. One of the main contributions of this work is to provide a mixed integer linear solution, to an otherwise non-linear problem, by exploiting the specifics of routing and aggregation sub-problems, while still maintaining the optimality of the solution. The formulation is generic and can handle varying amounts of traffic from each source to a common destination, as well as arbitrary aggregation fractions of the data coming from the different sources. This fraction is made to be a function of the number of the streams participating in the aggregation. For the heuristic solution we developed a Dynamic Programming style approach that builds the solution progressively, going through a number of stages, while choosing the best partial solutions among a number of possible partial solutions at each stage View full abstract»

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  • Assessing the economic benefit of introducing multi-granularity switching cross-connects in optical transport networks

    Page(s): 82 - 96
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (575 KB) |  | HTML iconHTML  

    In this article we assess the economic gain obtained by introducing multi-granularity switching optical cross-connects (MG-OXCs) in an optical transport network. An MG-OXC is an equipment able to switch wavelengths, to aggregate (disaggregate) wavelengths into (from) groups of wavelengths called wavebands and to switch wavebands. We evaluate the economic gain by comparing the cost of instantiating (i.e., provisioning) a set of Scheduled Lightpath Demands (SLDs) in a network of wavelength-switching optical cross-connects (WXCs) against the cost of instantiating them in a network of MG-OXCs. We formulate the problems of instantiating SLDs in both a network of WXCs and a network of MG-OXCs as two combinatorial optimization problems and compute approximate solutions to these problems using Tabu Search (TS) based algorithms. Finally, we define a method to determine the conditions (traffic distribution, cost of switching matrices and ports, etc.) under which a network of MG-OXCs is more economical than a network of WXCs View full abstract»

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  • A packet-switched hybrid optical network with service guarantees

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    We show that our proposed optical packet switched (OPS) hybrid network model supports both high throughput efficiency and guaranteed service transport (GST) with no packet loss and constant delay. The network comprises a wavelength routed optical network (WRON) enabling GST, and a statistically multiplexed (SM) network enabling high throughput. In the WRON, packets follow a fixed wavelength path and forwarding is based on the packets wavelength, while in the SM network, packets are switched according to header information. High reliability of GST packet forwarding is possible, because the forwarding does not depend on the operation of the packet switch. A novel node design supporting three Quality of Service (QoS) classes is proposed and described in detail. It facilitates full sharing of the link bandwidth by segregating GST packets and SM packets using polarization time division multiplexing (PTDM). SM packets are differentiated into two specified sub-QoS classes employing a novel buffer reservation technique and asynchronous buffer scheduling algorithm AIP3Q. We present a detailed analysis of the node throughput performance, demonstrating that buffering resource requirements are reduced in the optical packet switch, because processing and buffering of GST packets is avoided. The SM packet QoS differentiation permits a further reduction of buffer resources View full abstract»

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  • Optical fiber-delay-line buffer management in output-buffered photonic packet switch to support service differentiation

    Page(s): 108 - 116
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    We study optical fiber-delay-line buffer management schemes for supporting service differentiation with less complexity, with the objective of achieving ultra-high-speed packet forwarding in a photonic packet switch. We propose the vPBSO (Variable-length-packet-capable Partial Buffer Sharing with Overwriting) method, which is a prioritized buffer management scheme for providing DiffServ Assured Forwarding. This method can handle asynchronously arriving variable-length packets. vPBSO is based on a single queue, and its complexity is Oscr(p), where p is the number of priority classes. We show that vPBSO is effective when the arrival rate of higher priority packets is lower than that of lower priority packets, which is a likely situation in a prioritized system. vPBSO provides better performance than vPBS (an extension of partial buffer sharing) for high-priority packets, and the performance for low-priority packets is also better or at least almost the same. vPBSO provides service differentiation in the case of two or more priority classes in which the difference of packet loss probability in each class is made larger than one order of magnitude by appropriate tuning of thresholds View full abstract»

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  • Optical coarse packet-switched IP-over-WDM network (OPSINET): technologies and experiments

    Page(s): 117 - 127
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    Optical Packet Switching (OPS) has been envisioned as a prominent future optical networking technology for datacentric IP over Wavelength Division Multiplexing (WDM) networks, or optical Internet. Such OPS technology however raises significant transport and Quality of Service (QoS) challenges due to technological limitations. To circumvent OPS limitations, we have proposed a new Optical Coarse Packet Switching (OCPS) paradigm, which uses in-band-controlled per-burst switching and advocates traffic control enforcement to achieve high packet-loss performance and differentiated services. Based on OCPS, we have constructed an experimental IP-over-WDM network, referred to as OPSINET. OPSINET consists of two major types of nodes-edge routers, and Optical Label Switched Routers (OLSRs), and is facilitated with an out-of-band Generalized Multi-protocol Label Switching (GMPLS) control network. In this paper, we first introduce the OCPS paradigm. We then present the architecture of OPSINET, describe the in-band header/payload modulation technique, and detail the operations of the edge routers, OLSRs, and GMPLS control View full abstract»

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Aims & Scope

IEEE Journal on Selected Areas in Communications focuses on all telecommunications, including telephone, telegraphy, facsimile, and point-to-point television, by electromagnetic propagation.

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Meet Our Editors

Editor-in-Chief
Muriel Médard
MIT