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A novel routing and link dimensioning optimisation method which minimises the total wavelength requirements of dynamic optical WDM rings -the most popular topology in metropolitan networks- is proposed. The method finds the solution (set of routes) of minimum cost by solving an integer linear optimisation problem. Contrary to the common belief, results show that the optimal routes found by the proposed method are not necessarily balanced and that significant wavelength savings are achieved compared to the usual balanced-load routing approach in rings. This makes the proposed method the best choice for implementation in future dynamic WDM ring networks. [ABSTRACT FROM AUTHOR]

The problem of minimizing the number of optical nodes with signal regeneration capability can be constrained to guarantee a desired degree of end-to-end connectivity in the all-optical transport network. The problem can be formulated using a k-connected, k-dominating node set, which is a known approach in mobile ad hoc wireless networks. This paper presents a preliminary study aimed at establishing whether efficient centralized solutions to this problem in optical networking ought to be investigated to improve the decentralized solutions already available for wireless networks. [ABSTRACT FROM AUTHOR]

Typically, core networks are provided with both optical and electronic physical layers. However, the interaction between the two layers is at present limited, since most of the traditional transport functionalities, such as traffic engineering, switching and restoration, are carried in the IP/MPLS layer. In this light, the research community has paid little attention to the potential benefits of the interaction between layers, multilayer capabilities, on attempts to improve the Quality of Service control. This work shows when to move incoming Label Switched Paths (LSPs) between layers based on a multilayer mechanism that trades off a QoS metric, such as end-to-end delay, and techno-economic aspects. Such mechanism follows the Bayesian decision theory, and is tested with a set of representative case scenarios. [ABSTRACT FROM AUTHOR]

This paper discusses different capacity leasing scenarios for the optical network. It aims at providing systematic understanding of cost structure of optical networks, without focusing on technical details. It reviews different kinds of capacity leasing approaches discussing the relative costs and the flexibility associated to them to adapt to future traffic needs. Then it applies the Real Options principles to evaluate the most convenient planning solution. Real Option valuation is shown to be the formalization of the natural way of valuating different alternatives under uncertainty, taking into account that information becoming available during the course of the planning horizon might influence the strategy followed. The goal of the paper is to give insight in the practical applicability of the technique for the network operator. [ABSTRACT FROM AUTHOR]

To ensure efficient data transmission for multimedia services in Ethernet passive optical networks (EPON) which are considered as a promising solution to the last-mile problem in the broadband access network, they employ the media access control (MAC) mechanism by sharing efficiently the bandwidth of all optical network units (ONUs) and by avoiding data collisions in the upstream channel. The representative dynamic bandwidth allocation scheme, Interleaved Polling with Adaptive Cycle Time (IPACT), is considered as a standard approach in services for requests of ONUs. It reduces the performance of the entire network in terms of mean packet delay and packet loss ratio, due to congestion for the case that an ONU has burst traffic or highly loaded traffic. To handle this, the proposed scheme varies the cycle length in the basic period center and guarantees a maximum window size per ONU. In this paper, the proposed scheme demonstrates enhanced performance in terms of mean packet delay and packet loss ratio, of up to 58% and 10%, respectively. [ABSTRACT FROM AUTHOR]

An adaptive approach is used to adjust the transmit power of each beam in a line strip multi-beam optical transmitter based on information about the quality of the received signal due to each spot. The system assumes a feedback link between the optical transceivers. Diversity detection is employed to combat the degrading effect of the background noise in the channel with a 7- detectors angle diversity receiver. Both the optical transmitter and the multibranch receiver are fully mobile. The performance of the system is evaluated for two weakest links and compared against that of a non-adaptive spot diffusing transmitter. Our results show that the adaptive transmitter produces a considerable gain of 12.9 dB in signal-to-noise-ratio (SNR) when the distance separating the transceivers is largest in the case of a non mobile transmitter. Furthermore, a 6.8 dB increase in SNR is obtained for the mobile transmitter compared to the non-adaptive transmitter's scenario. [ABSTRACT FROM AUTHOR]

In this paper a novel adaptive bandwidth allocation scheme called Prudent Creditization Polling (PCP) is proposed and adapted with the reservation protocol IPACT. PCP attempts to reduce the average queue length at the ONUs and the average packet delay throughout the network. At each polling period, PCP attempts to creditize the request of the ONUs that suffer from high RTT, high average delay per packet, and high buffer growth. We implemented PCP with a fuzzy functional approach and a linear regression approach. We simulated PCP and several service disciplines in IPACT and compared their performance in terms of average packet delay and queue length. We show that PCP improves the performance of IPACT significantly in terms of the performance metrics aforementioned. [ABSTRACT FROM AUTHOR]

A novel algorithm for fast dimensioning of end-to-end optical burst switching networks is proposed. The proposed method determines the number of wavelengths for each network link according to the traffic load, the routing algorithm and the required blocking probability per connection. The burst input traffic is modeled by an ON-OFF alternating renewal process, which is more realistic for OBS networks than the typically used Poisson model. Compared to the two most typically used dimensioning approaches, the proposed method results in significant lower wavelength requirements whilst achieving the same target blocking probability. Additionally, the proposed method takes less than one second to dimension the network links which makes it several orders of magnitude faster than the conventional simulation approach. [ABSTRACT FROM AUTHOR]

Optical Burst Switching (OBS) is widely believed to be the technology for the future core network in the Internet. Burst assembly time at the ingress node is known to affect the traffic characteristics and loss distribution in the core network. We propose an algorithm for adapting the burst assembly time based on the observed loss pattern in the network. The proposed Learning-based Burst Assembly (LBA) algorithm uses learning automata which probe the loss in the network periodically and change the assembly time at the ingress node to a favorable one. We use a discrete set of values for the burst assembly time that can be selected and assign a probability to each of them. The probability of selecting an assembly time is updated depending on the loss measured over the path using a Linear Reward-Penalty (LR − P) scheme. The convergence of these probabilities eventually leads to the selection of an optimal burst assembly time that minimizes the burst loss probability (BLP) for any given traffic pattern. We present simulation results for different types of traffic and two network topologies to demonstrate that LBA achieves lower BLP compared to the fixed and adaptive burst assembly mechanisms existing in the literature. [ABSTRACT FROM AUTHOR]

We propose new burst assembly techniques that aim at reducing the average delay experienced by the packets during the burstification process in optical burst switched (OBS) networks, for a given average size of the bursts produced. These techniques use a linear prediction filter to estimate the number of packet arrivals at the ingress node in the following interval, and launch a new burst into the network when a certain criterion, which is different for each proposed scheme, is met. Reducing the packet burstification delay, for a given average burst size, is essential for real-time applications; correspondingly, increasing the average burst size for a given packet burstification delay is important for reducing the number of bursts injected into the network and the associated overhead imposed on the core nodes. We evaluate the performance of the proposed schemes and show that two of them outperform the previously proposed timer - based, length - based and average delay-based burst aggregation schemes in terms of the average packet burstification delay for a given average burst size. [ABSTRACT FROM AUTHOR]

Optical Burst Switching (OBS) is a promising switching paradigm to efficiently support Internet Protocol (IP) packets over optical networks, under current and foreseeable limitations of optical technology. The prospects of OBS networks would greatly benefit, in terms of cost and ease of implementation, from limiting the wavelength conversion capabilities at the network nodes. This paper presents a framework for contention minimization/resolution combining traffic engineering in the wavelength domain to minimize contention in advance and optical buffering at the core nodes to resolve contention. Simulation results show that with the proposed contention minimization/resolution framework the large number of expensive all-optical wavelength converters used at the core nodes of an OBS network can be replaced by a moderate number of shared optical delay lines without compromising network performance. [ABSTRACT FROM AUTHOR]

The Optical Burst Switching (OBS) technology emerged as an alternative switching paradigm for the optical transport layer. Its biggest disadvantage (high data losses) has been the focus of numerous research papers. This paper proposes a data loss reduction technique, which relies on the combination of global network coordination between network nodes and local contention resolution. Via full-scale network simulation it is demonstrated that the proposed scheme has improved performance in terms of data losses and resource utilization, compared to its constituent mechanisms alone. Furthermore, the effectiveness of the mechanism has proven to be less sensitive to load variations in the medium and high load ranges. Additionally, its complexity and deployment cost are low, due to the absence of immature optical components in the network. [ABSTRACT FROM AUTHOR]

Active queue management (AQM) is an important function in today's core routers that will be required in the future optical internet core. A recently reported novel architecture for optical packet buffers is extended by implementing necessary AQM functions. The suggested AQM scheme is validated and explore via simulations. [ABSTRACT FROM AUTHOR]

We propose an online traffic engineering (TE) scheme for efficient routing of bandwidth guaranteed connections on a Multiprotocol label switching (MPLS)/wavelength division multiplexing (WDM) network with a traffic pattern varying with the time of day. We first consider the problem of designing the WDM virtual topology utilizing multi-hour statistical traffic pattern. After presenting an effective solution to this offline problem, we introduce a Dynamic tRaffic Engineering AlgorithM (DREAM) that makes use of the bandwidth update and rerouting of the label switched paths (LSPs). The performance of DREAM is compared with commonly used online TE schemes and it is shown to be superior in terms of blocked traffic ratio. [ABSTRACT FROM AUTHOR]

WDM technology has increased network link capacity dramatically, moving the network bottleneck from the transport to the routing layer. Hybrid electro-optical architectures seem at the moment a reliable and cost-effective solution for near-future implementations of the routing/switching layer. In this paper we present a novel approach to dynamic optical circuit switching based on the Optical IP Switching (OIS) model. OIS nodes classify IP packets by destination prefix, aggregating them into dynamically created optical paths. We report simulation results based on real traffic traces collected from the pan-European GÉANT network. [ABSTRACT FROM AUTHOR]

We present a new algorithm based on ant colony optimization to solve the dynamic routing and wavelength assignment problem in a distributed manner. The algorithm uses the ant colony optimization metaheuristic to obtain updated information about the network state, which is then used to find the routes and wavelengths to establish new connections through an adaptive process able to deal with dynamic changes in network state. By means of simulation we show that the algorithm leads to lower blocking probability and lower mean setup time than other distributed algorithms. [ABSTRACT FROM AUTHOR]

In this paper we propose an enhanced parallel iterative scheduler for IBWR synchronous slotted OPS switches in SCWP mode. It obtains a maximal matching of packet demands without resource conflicts. The analytical and numerical results are highly competitive regarding previous work. [ABSTRACT FROM AUTHOR]

A more flexible routing of better performance can be achieved in multilayer networks when the controllers of different network layers are "peering" instead of "overlaying", i.e., instead of the simple overlay model the peer interconnection or the vertically integrated model is used, and Label Switched Paths are searched in a Wavelength Graph that represents the network state very accurately. However, routing in "Peer network" does not only require large databases for storing the Wavelength Graph and complex path-search algorithms, it also increases the load of control channels, as more link state changes must be advertised. Much of the link state information is, however, redundant as the state changes are not independent. In this paper we propose a method for topology information advertisement and maintenance to significantly reduce the amount of control messages without deteriorating the quality of routing. [ABSTRACT FROM AUTHOR]

Today's data transport networks are evolving continuously towards customer oriented and application aware networks. This evolution happens in Europe in a highly diverse network environment, covering multiple network domains, layers, technologies, control and management approaches. In this paper, the issues, challenges and the solutions developed in the IST project MUPBED (,,Multi-Partner European Test Beds for Research Networking"; www.ist-mupbed.eu) for seamless interworking in a typical European heterogeneous network environment are described, addressing horizontal, interdomain, and vertical, inter-layer topics related to data plane, control plane and applications. [ABSTRACT FROM AUTHOR]

In this paper we investigate and evaluate the performance of multicast routing in grooming capable multi-layer optical wavelength division multiplexing (WDM) networks. New wavelength-graph models are proposed for network equipments capable of optical-layer branching of light-paths. We evaluate the cost-effectiveness of electronic and optical-layer multicast and unicast as well. The high scalability of optical multicast against unicast is also showed. All routing and technical constraints are formulated in ILP and realized in our versatile simulator. [ABSTRACT FROM AUTHOR]

We present a clustering algorithm for hierarchical traffic grooming in large WDM networks. In hierarchical grooming, the network is decomposed into clusters, and one hub node in each cluster is responsible for grooming traffic from and to the cluster. Hierarchical grooming scales to large network sizes and facilitates the control and management of traffic and network resources. Yet determining the size and composition of clusters so as to yield good grooming solutions is a challenging task. We identify the grooming-specific factors affecting the selection of clusters, and we develop a parameterized clustering algorithm that can achieve a desired tradeoff among various goals. [ABSTRACT FROM AUTHOR]

Testbeds play a key role in the evolution of GMPLS-based Intelligent Optical Networks (ION) proving grounds in which new optical networking research ideas (e.g., new constraint-based routing algorithms) can be tested and evaluated. In order to be a productive experimentation environment, a GMPLS optical network testbed should be flexible, allowing the reconfiguration of as many different network topologies and configurations as possible. But usually this flexibility comes at the expense of high management costs when switching from one scenario to another is performed through time-consuming error-prone manual procedures. This paper describes an automatic model-based deployment mechanism that overcomes the limitations of manual reconfigurable testbeds, allowing high flexibility without involving high management costs. The model-based approach is not only suitable for deployment (and undeployment) but also for monitoring. The practical application of the mechanism to ADRENALINE testbed (a GMPLS-based all-optical transport network developed at CTTC) with the ADNETCONF tool is also described. [ABSTRACT FROM AUTHOR]

Transparent optical networks need novel connection management approaches to take into account the presence of physical impairments in lightpath provisioning. Two main schemes are emerging from literature when considering how to introduce impairment-aware mechanisms in a distributed optical control plane like GMPLS. A well-known approach is based on extending the routing protocol to compute an optically-feasible light-path. Lately, a new approach is emerging which keeps the routing protocol unmodified while leveraging on signaling protocol extensions to find the proper lightpath for the incoming connection request. The aim of this paper is to prove that the signaling-based approach has several advantages compared to the routing-based one, in term of scalability and robustness especially when link information changes are frequent in the network. Simulation results show that a signaling-based approach is much more robust to inaccurate information about network status, therefore it is a suitable approach for considering physical impairments in dynamic optical networks. [ABSTRACT FROM AUTHOR]

The reduction of both deployment costs and operating expenses has emerged as a critical goal of next-generation optical networks. In this context, as each node maintains a large number of input/output ports (i.e. wavelengths, fibers, time slots ...), automation is needed to reduce long and tedious manual node configurations, thus easing network management and minimizing resource misconfiguration probability. In this paper, we present two novel mechanisms which permit GMPLS Link Management Protocol to deal with the resource discovery of all-optical meshed transport networks. The subsequent evaluation demonstrates their applicability over large meshed network topologies with considerably high nodal degrees. [ABSTRACT FROM AUTHOR]

In this paper we study the performance of several routing algorithms for optical burst switching network. The main aim is to find ways for performing dynamic load balancing and reduce congestion situation. In our analysis, we consider a common network scenario and, as a performance reference, we use the simple shortest path routing giving results of both analytical and simulation models. Therefore we propose many different routing algorithms based either on adaptive or non-adaptive strategies as well as distributed or isolated path selection. The obtained results highlight that none of the proposed strategies improve significantly the performance over the simple shortest path approach in the considered scenarios. [ABSTRACT FROM AUTHOR]

This paper addresses the problem of routing optimization in optical burst switching (OBS) networks. We use a simplified analytical model of OBS network with an overall burst loss probability as the primary metric of interest. Since the objective function of optimization problem is nonlinear we propose two solutions based on a non-reduced link load (NR-LL) model and a reduced link load (R-LL) model. In order to find partial derivatives of the cost function we apply a calculation considered previously for circuit-switched networks. We derive exact partial derivatives of NR-LL model and we approximate the partial derivatives of R-LL model. Simulation results demonstrate that our solutions effectively reduce the overall burst loss probability over the shortest path routing. Moreover, in many cases, they over-perform an alternative routing. [ABSTRACT FROM AUTHOR]

Transmission Control Protocol (TCP) performance over optical burst switching (OBS) is experimentally investigated on an OBS network testbed. The effect of burst losses on TCP performance over the OBS testbed is studied and the result shows that burst losses will lead to a network wide drop in TCP throughput and there exists an optimal assembly period to maximize the available TCP bandwidth. Then a new assembly mechanism constraining the ratio of acknowledgement (ACK) number to all the segment number in one burst is proposed. Simulation results demonstrate that compared with conventional assembly mechanism, the new one can improve TCP performance over OBS networks to great extent with lower network burst loss probability and higher TCP throughput. [ABSTRACT FROM AUTHOR]

An LOBS testbed is briefly introduced and TCP performance over OBS is experimentally investigated. Simulation and experimental results show that TCP performance is displayed differently with the loss of ACK (TCP Acknowledgement) burst and data burst. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to assess the impact of timer-based burst assembly algorithms for TCP traffic. We present an analysis for short, medium and long assembly times and investigate segment and flow distribution over the assembled bursts. Further, we also analyze their impact on the congestion window evolution and on the effective throughput achieved. It has been found out that short assembly times are ideally suitable for sources with small congestion windows, allowing for a speed up, while large assembly times yield a lower throughput variation among the individual assembled flows. For long assembly times, the transfer of more segments from the same source is trading off the increase of the burstification delay but no throughput gain is obtained. However, large assembly times smooth out individual flow performance and provide a significant lower variation of throughput. To this end, in this paper, we propose a new adaptive burst assembly algorithm that dynamically assigns flows to different burstifiers based on their instant window size. [ABSTRACT FROM AUTHOR]

In this paper, several key technologies of optical burst switching (OBS) network are implemented and experimentally verified. The TCP performance over OBS is experimentally investigated on this testbed and multi-QoS traffic transmission on the testbed are demonstrated as well. Currently, an interconnection experiment between OBS and GMPLS network are also reported. [ABSTRACT FROM AUTHOR]

Government-funded R&D initiatives have been playing crucial roles for developing photonic networks. The R&D project is typically carried out for a relatively long period of five-years, and the goal is set so high that no single private sector can afford the risk. In this paper, challenging government-funded R&D initiatives of photonic networks in Japan is introduced. They have been launched in 2006, which aims to establish the photonic platform to provide abundant bandwidth on demand, at any time and from anywhere, to promote bandwidth-rich networked applications. In addition, other government-funded R&D activities relevant to the photonic networks in Japan is also presented, including photonic devices and subsystems and large-scale optical interconnect for ultra-high performance computing. [ABSTRACT FROM AUTHOR]

An OpMiGua node integrates a packet switch for low priority traffic and a circuit switch for high priority traffic. Both traffic classes share the same input and output ports using time division multiplexing, but absolute priority is given to circuit switched packets. The circuit switched packets do not experience contention at output ports and are not subject to delay jitter; hence a guaranteed service class is created. Previous studies of OpMiGua nodes have used one of two reservation techniques to assure priority; either a time-window approach or a preemptive approach. This article introduces two new reservation techniques and investigates advantages and drawbacks associated with the four techniques. It is shown that each reservation technique is associated with specific loss mechanisms and methods to reduce their influence are proposed. Simulation results demonstrate that the choice of reservation technique is highly influenced by the relative share and length of high priority packets. [ABSTRACT FROM AUTHOR]

Current GMPLS protocols can be used in a Grid enabled environment by properly defining a new interface between Grid and Transport layers. However, the asymmetric nature of Grid traffic makes GMPLS inefficient when establishing bidirectional connections. The User to Grid traffic is unlikely to be the same as the Grid to User traffic; whilst the location of the processing sites may be of no importance to the user, the destination address of the Grid to User downstream is the same for all the different flows akin to the same job. This may result in asymmetric resource allocation throughout the network. We propose and experimentally evaluate an implementation for a middleware interface as well as a novel scheme that reduces blocked job requests due to lack of network resources in such environment. [ABSTRACT FROM AUTHOR]

This paper presents results from the IST Phosphorus project that studies and implements an optical Grid test-bed. A significant part of this project addresses scheduling and routing algorithms and dimensioning problems of optical grids. Given the high costs involved in setting up actual hardware implementations, simulations are a viable alternative. In this paper we present an initial study which proposes models that reflect real-world grid application traffic characteristics, appropriate for simulation purposes. We detail several such models and the corresponding process to extract the model parameters from real grid log traces, and verify that synthetically generated jobs provide a realistic approximation of the real-world grid job submission process. [ABSTRACT FROM AUTHOR]

In this paper we discuss the use of the Session Initiation Protocol (SIP) as part of the control plane of an application aware Optical Burst Switching (OBS) network, able to support Grid computing applications. The paper presents the possible alternatives for the architecture of such control plane and reports of an experiment in an existing OBS test-bed where this approach was successfully tested in practice. [ABSTRACT FROM AUTHOR]

We demonstrate the applicability of quantum-dot semiconductor-optical-amplifier based wavelength converters to the implementation of an ultra-high speed optical packet switching buffer. The buffer architecture consists of cascaded programmable delay stages that fully utilize the available wavelengths and thus minimize the number of wavelength converters that are required to implement the buffer. Physical layer simulations demonstrate error-free operation of the buffer with 3 cascaded Time-Slot-Interchager (TSI) stages at 160 Gbps in the 1.55um window. [ABSTRACT FROM AUTHOR]

We propose a novel optical switching system using fast time-slotted passive switching with shared OEO buffers. Simulation results show that the proposed system significantly reduces the blocking probability below 10− 6 at a 28% cost of a traditional system due to flexibility of contention resolution using electrical buffer and potentially requires very low power consumption. The proposed switching system is believed to be a technoeconomically feasible and implementable solution for optical packet and burst switching with current optical technologies. [ABSTRACT FROM AUTHOR]

Passive optical access networks are susceptible to intended attacks and unintended failures. This paper discusses intrusion by user-side signal-injection resulting in reduced network accessibility and it proposes possible countermeasures. The central function is that an intruding signal can be switched off when it is present. [ABSTRACT FROM AUTHOR]

A highly-scalable access architecture achieving high-user-density and enabling resiliency, centralized light-generation control, remote amplification and colorless ONU with Reflective Semiconductor Optical Amplifier (RSOA) is presented as the bridge between the already deployed Fiber-to-the-Home infrastructures and the advanced optical access networks. A techno-economical comparison of these optical access networks is done, depicting the proposed solution -SARDANA- as the most cost effective migration path towards the Next Generation Passive Optical Networks. [ABSTRACT FROM AUTHOR]

All optical signal processing is a fundamental concept on which the next generation networks will be based. Implementation of key functionalities as multiwavelength regeneration, frequency conversion and high data rate demultiplexing performed all optically becomes a primary target in current research scenario. In this work, demultiplexing of high data rate signals is demonstrated. The base for the functionality is the cross phase modulation occurring in a span of highly non linear fiber. This fiber is designed to have low birefringence, therefore quite adapted for processing polarization dependent processes, which are the base for the achieved functionality. Demultiplexing from 40GHz and 80GHz to 10GHz is demonstrated. [ABSTRACT FROM AUTHOR]

Transparent optical mesh networks are an appealing solution to provide cost-effective high bandwidth connections eliminating the need of expensive intermediate electronic regenerators. However, the implementation of transparent optical networks requires to take into account physical impairment information for effective lightpath set-up. In this paper, we present two distributed solutions to encompass physical impairments based on enhancements of the GMPLS protocol suite. Specifically, both GMPLS routing protocol and signaling protocol extensions are presented and discussed. An alternative centralized approach based on an impairment-aware Path Computation Element (PCE) is also proposed. The distributed routing approach exhibits convergence limitations, while the distributed signaling approach is scalable and effective. The latter is then compared against the centralized PCE approach through simulations considering both a metro network and a more complex WDM network scenario. In addition, experimental implementations of the two approaches are presented. Results show the trade-off of the two approaches, demonstrating the general good performance in terms of lightpath set up time for both approaches. [ABSTRACT FROM AUTHOR]

This paper presents the MatPlanWDM tool, an educational network planning tool for wavelength-routing WDM networks. It includes a set of heuristic algorithms for solving the virtual topology design, and the routing and grooming of traffic flows on top of it. In addition, an implementation of the linear programming problem to obtain the optimal solution of the complete design is included for comparison. The input parameters to the planning problem are the network physical topology, the traffic matrix, and technological constraints like the number of transmitters, receivers, optical converters and wavelengths available. The tool is implemented as a MATLAB toolbox. The set of heuristic algorithms can be easily extended. A graphical interface is provided to plot the results obtained from different heuristics and compare them with the optimal solution in small-scale topologies. [ABSTRACT FROM AUTHOR]

We investigate new routing and wavelength assignment algorithms considering as constraints physical impairments that arise in transparent networks. Accounting both linear and nonlinear impairments we propose a scheme that integrates the routing and wavelength assignment to achieve an optimal combination of physical and networking performance. Through simulations of a typical long haul network the improvement achieved using the proposed approach compared to conventional RWA algorithms (i.e shortest path and first fit) is demonstrated and the significance of impairment aware routing and wavelength assignment schemes is recognized. [ABSTRACT FROM AUTHOR]

In both, metropolitan optical networks (MON) and long haul optical networks (LHON) the signal quality is often influenced by the physical impairments, therefore a proper impairment based routing decision is needed. In the absence of all-optical 3R regenerators, the quality of transmission has a strong impact on the feasibility of all-optical transmission. It is assumed that signal regeneration can be done only in electrical layer. Once the signal is in electrical layer there are some features supported e.g. the traffic grooming. We show that by taking into account both, the physical impairments characterized by the Q-factor, as we propose, and the features of the electrical layer, will have a strong impact onto the routing that is based on impairment constraints. [ABSTRACT FROM AUTHOR]

We investigated impairments of optical packets when these packets amplified by cascaded EDFAs in several distinctive cases in WDM environment. The origin of impairments were mainly gain excursion and additional noise come from inter-channel cross talk between WDM channels, and the degree of impairment changed according to link utilization. Moreover, the impairment is cumulative by increase of the number of EDFAs cascaded. It means that the tolerance for error of optical packet receiver substantially reduces according to the traffic intensity and the number of hops each packet experiences. We proposed the mitigation by adopting special class of EDF which have larger active erbium core. Our methodology can supplement conventional electrical controlling measures against transient responses which have insufficient response speed in the application for short optical packet of sub-micro seconds long. [ABSTRACT FROM AUTHOR]

We demonstrate an optically controlled 2x2 Crossbar switch suitable for all-optical switching architectures. The switch is based on an Ultrafast Nonlinear Interferometer (UNI) configuration and uses 80 centimeters of highly nonlinear Bismuth Oxide fiber. Error-free operation is demonstrated with 10 and 40 Gb/s input signals, with power penalties in its BAR and CROSS states of less than 0.3 dB and 1 dB respectively. The short length of the highly nonlinear Bismuth Oxide fiber ensures compact size, small latency and good operational stability of the switch. [ABSTRACT FROM AUTHOR]

This paper proposes 80Gb/s multi-wavelength optical packet switching(OPS) using a PLZT switch. The Multi-wavelength OPS Network can achieve low implementation costs compared to existing OPS networks in which the number of wavelengths is large. In this network, the header is processed separately from the payload. The payload is divided into multiple segments. Each segment is then encoded into different wavelengths. After assignment of wavelength to each payload segment, payload segments are multiplexed into an optical signal which is then transmitted through an optical fiber. Therefore, the number of components required for intermediate node functionality stays the same for the number of wavelengths used for payload transmission. This paper shows a fundamental experiment of the Multi-wavelength OPS network using a PLZT switch. PLZT switch provide a fast optical switching with low noise, independent polarization, and low drive voltage. In this paper, we describe the detail of the experiments and results. [ABSTRACT FROM AUTHOR]

The electronic layer multicast is going to face the speed and capacity bottleneck of the future optical data networks. Transparent optical wavelength multicast by multi-wavelength conversion is an effective way of achieving data multicast in the optical domain without any optical-electronic-optical conversion. In this paper, two multiple wavelength conversion technologies for 10 Gb/s data rate are investigating and discussed. The first technology is based on cross-phase modulation in a semiconductor optical amplifier - Mach-Zehnder interferometer, and the second is based on four-wave mixing in a dispersion-shifted fiber. We present the simulated performance comparison of two approaches obtained using VPItransmissionMakerTMWDM simulator. Afterwards, we analyze these results in comparison with our previous experimental results of the same schemes. [ABSTRACT FROM AUTHOR]

In highly dynamic large IP/MPLS networks, when routing information includes not only topology information but also information to provide QoS, such as available link bandwidth, network state databases must be frequently updated. This updating process generates an important signaling overhead. Reducing this overhead implies having inaccurate routing information, which may cause both non-optimal path selection and a call-blocking increase. In order to avoid both effects in this paper we suggest a new QoS explicit routing mechanism called BYPASS Based Routing (BBR), which is based on bypassing those links along the selected path that potentially cannot cope with the traffic requirements. Routing algorithms derived from the proposed BBR mechanism reduce the call-blocking ratio without increasing the amount of routing control information. [ABSTRACT FROM AUTHOR]