This PDF file contains the front matter associated with SPIE Proceedings Volume 7989, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.

We propose a 2-stage ILP-based design algorithm for hierarchical optical path networks that utilize hybrid-HOXCs. The hybrid-HOXC consists of an optical waveband cross-connect and an electrical cross-connect which grooms only wavelength paths. Its effectiveness is evaluated through numerical experiments. Impact of electrical/optical port cost ratio on the total network cost is also investigated.

This paper proposes an inter-domain routing algorithm for multi-domain WDM networks based on hierarchical PCE architecture. The proposed algorithm presents a strategy of selecting k random paths in parent PCE. The simulation indicates that the proposed algorithm outperforms previous methods in term of blocking probability and resource utilization.

In this paper, we analyze the impact of configuration time on network performance in GMPLS based WDM networks, and propose a modified destination-initiated reservation (M-DIR) approach to reduce the impact.

We propose a concurrent collision avoidance scheme based on wavelength rotation (WR) in optical WDM networks. By introducing wavelength cost during the path computation process, the proposed scheme can significantly reduce the concurrent blocking probability (BP), without introducing additional connection setup delay compared with the time-threshold- based concurrent RWA schemes.

Generalized Survivable Network (GSN) can improve the performance of Optical Flow Switched (OFS) network in short flow scenario (< 1 second) and enhance the application of OFS network. The design problem of OFS network with GSN becomes an important problem. In this paper, we propose a solution approach to solve the problem of designing OFS network with GSN for arbitrary mesh topologies. We demonstrate the performance of our proposed approach by some numerical experiments.

In order to solve the wavelength resource reserve collision problem in distributed wavelength assignment senario for PCE/GMPLS-based WSONs, a half-centralized wavelength assignment scheme has been proposed, which efficiently avoids the collision by adding several functions to PCE and doing some extensions to the GMPLS signaling. Simulation results show that the proposed scheme performs much better in decreasing total blocking probability than two traditional ones under various traffic conditions, especially when the traffic load is low while the arrival rate is high.

This paper analyzes the connection availability of a protection paradigm, termed permanent dedicated path protection (PDPP), in WDM mesh networks. Numerical results on COST239 European network show that P-DPP reduces the average connection unavailability compared with the traditional dedicated path protection (DPP) at the cost of higher capacity utilization.

A cost-effective and service-differentiated provisioning strategy is very desirable to service providers so that they can offer users satisfactory services, while optimizing network resource allocation. Providing differentiated protection services to connections for surviving link failure has been extensively studied in recent years. However, the differentiated protection services for workflow-based applications, which consist of many interdependent tasks, have scarcely been studied. This paper investigates the problem of providing differentiated services for workflow-based applications in optical grid. In this paper, we develop three differentiated protection services provisioning strategies which can provide security level guarantee and network-resource optimization for workflow-based applications. The simulation demonstrates that these heuristic algorithms provide protection cost-effectively while satisfying the applications' failure probability requirements.

Physical-layer attacks, such as power jamming, can present a serious security threat to transparent optical networks. We present a novel security framework based on protection using attack-aware planning, with the objective to minimize the potential damage caused by various attack scenarios in a cost-effective manner.

Optical receiver sensitivity for electronic code division multiple access over a passive optical network (ECDMA-PON) is analyzed theoretically. Compared with TDM system, ECDMA-PON offers better receiver sensitivity due to coding gain. Fundamental simulation results are provided to show its validity.

This paper presents a comprehensive cost model for migration towards FTTH, some case study results from different network area scenarios, as well as the identification of the most important cost factors to be considered by operators aiming at increasing the profitability of their networks.

We propose a simple configuration of wavelength-tunable self-seeding Fabry-Perot fiber laser at ONUs for upstream transmission in hybrid WDM/TDM PON. The performances of the side-mode suppression ratio (SMSR), tuning range, wavelength and power stability for the proposed laser module are experimentally investigated. The performance benefits from the upstream wavelengths sharing are showed via simulations.

The Hybrid WDM/TDM PON, which combines Wavelength-division multiplexing (WDM) with TDM technology, is presented as a promising solution for the next generation of optical access network. To realize the statistical multiplexing of upstream wavelength resources, some optical tunable components are introduced in the optical network unit (ONU). However, switch latency (SL) of these components is an important parameter that will constrain the performance of Hybrid WDM/TDM PON. In this paper, we for the first time demonstrate and analyze the effect of channel switch latency (SL) based on the extended WDM IPACT scheme via simulations. The simulation results show that the performance such as delay, packet lost ratio, queue length and utilization will be constrained by SL, and the WDM-IPACT-SL can adaptively adjust the channel switch time according to the different SL so as to reduce the degeneration of the network performance in the practical applications of. Hybrid WDM/TDM PON

To provide end-to-end wide-bandwidth data transfer over lambda and Ethernet networks, we demonstrate dynamic circuit provisioning by web services interface proxy which enables interoperability among different network provisioning systems.

This paper presents the novel idea of using a GMPLS control plane for all flavors of an IEEE 802.1Q multilayer Ethernet, applied to an access and aggregation network scenario. Such a network could provide better resilience, control of resource allocation, bandwidth guarantees and the possibility of having a unified control plane in an environment that includes more and more type of forwarding technologies. It might also be possible to reuse existing equipment and provide backward compatibility for legacy systems when deploying such a GMPLS network over an existing Ethernet based network. This was accomplished through extending GMPLS protocols by defining a new switch capability object, new label object for ML Ethernet, and the development of control plane procedures for handling scenarios specific to ML Ethernet. These extensions has been implemented and verified, along with the development of a ML Ethernet aware PCE, and the results indicates that this novel architecture is plausible and has an interesting potential.

A unified control plane is necessary to be designed for multi-layer optical networks, especially for IP over WDM networks to improve the performance and efficiency of the entire networks. According to the advantages of PCE, a PCE-based unified control plane framework is designed. This paper mainly focuses on the framework of PCE-based unified control plane, and proposes a novel PCE-based traffic grooming strategy in the unified control plane to reduce the collision of resource in distributed control plane. Based on this strategy, four PCE-based traffic grooming algorithms are proposed and compared with the distributed traffic grooming strategy without PCE on a simulation platform implemented using disperse event simulation tool OMNeT++. On the other hand, power consumption problem in optical networks, especially in IP over WDM optical networks, becomes rigorous, and attracts more and more attentions, and power consumption model is the key to solve the power consumption problem. In this paper, power consumption model based on different service LSPs is built for IP over WDM optical networks. A power-aware traffic grooming algorithm is proposed and compared with two traditional traffic grooming algorithms on the NSFNET topology. Numeric results show that the power-aware traffic grooming can get low power consumption without increasing the blocking probability.

We propose a dynamic RWA method for optical path networks that pre-computes route candidates to attain better load-balancing. Numerical experiments elucidate that the proposed method can accommodate 1.4-1.8 times more traffic than the conventional method that ignores load-balancing.

In next generation networks (NGN) architecture which is standardized in ITU-T, Ri interface is defined as the interdomain QoS control interface between Resource Admission and Control Function (RACF). By the coordination of NGN operators using Ri interface, it is expected that more users can obtain high quality network services. However, neither the design of functional architecture for inter-domain QoS control of RACF nor the control sequence of Ri interface are provided so far. In this paper, a session-based resource management capability for inter-domain QoS control is demonstrated for the first time. For a video-on-demand application, the extended RACF is applied and the resource reservation over different NGN-domains is successfully conducted.

Network Virtualization Technology is serving as an effective method for providing a flexible and highly adaptable shared substrate network to satisfy the diversity of demands. But the problem of efficiently embedding Virtual Network (VN) onto substrate network is intractable since it is NP-hard. How to guarantee survivability of the embedding efficiently is another great challenge. In this paper, we investigate the Survivable Virtual Network Embedding (SVNE) problem and propose two efficient algorithms for solving this problem efficiently. Firstly, we formulate the model with minimum-cost objective of survivable network virtualization problem by Mixed Integer Linear Programming (MILP). We then devise two efficient relaxation-based algorithms for solving survivable virtual network embedding problem: (1) Lagrangian Relaxation based algorithm, called LR-SVNE in this paper; (2) Decomposition based algorithm called DSVNE in this paper. The results of simulation experiments show that these two algorithms both have good performance on time efficiency but LR-SVNE can guarantee the solution converge to optimal one under small scale substrate network.

Network virtualization is a promising solution that can prevent network ossification by allowing multiple heterogeneous virtual networks to cohabit on a shared substrate network. Thus using virtualization multiple customizable networks can be run on the same underlying substrate network resulting in an increase in network flexibility and services. A key issue that needs to be addressed in virtualization is the mapping of the virtual networks to the resources of the underlying physical network. In this paper we present an improved virtual network mapping algorithm based on subgraph isomorphism, which not only improves on the cost or resource efficiency of the mapping but is also computationally efficient.

Energy efficiency of high-performance network elements can be improved through using low-power-consuming technologies such as high-speed optical transmission and signal processing as well as by developing and applying novel network concepts optimized for both energy and performance. This paper briefly discusses potentials and options for achieving highly energy-efficient network elements.

A MILP based optimization model called PVTR is proposed for energy reduction in IP over dynamic optical networks. By periodical virtual topology reconfiguration, it is able to dynamically switch off unnecessary networking equipments, and reduce the energy consumption caused by over-provision. Simulation results indicate that the proposed approach can significantly improve network performance, and is proved to be a suitable manner for energy saving.

An energy efficiency scheme based on the coordination of management and control is proposed to reduce the power consumption in multi-domain WSON. Experiments are conducted on the energy efficient multi-domain WSON testbed (EEMWT) to assess the performance of the scheme.

Network planning and operation have a complementary relationship with each other. In this paper, we show the benefits of cooperation of network planning and operation. We also clarify network planning functionality required to let service providers sustainably operate their networks with low cost.

This paper presents an energy-efficient Medium Access Control (MAC) protocol for very-high-throughput millimeter-wave (mm-wave) wireless sensor communication networks (VHT-MSCNs) based on hybrid multiple access techniques of frequency division multiplexing access (FDMA) and time division multiplexing access (TDMA). An energy-efficient Superframe for wireless sensor communication network employing directional mm-wave wireless access technologies is proposed for systems that require very high throughput, such as high definition video signals, for sensing, processing, transmitting, and actuating functions. Energy consumption modeling for each network element and comparisons among various multi-access technologies in term of power and MAC layer operations are investigated for evaluating the energy-efficient improvement of proposed MAC protocol.

In this paper, we have proposed and demonstrated a novel architecture for orthogonal frequency division multiplexing wavelength-division-multiplexing passive optical network (OFDM-PON) with centralized lightwave and differential phase shift keying (DPSK) broadcast overlaid. In the architecture, 10-Gb/s 16QAM-OFDM point to point (P2P) signals and 2.5-Gb/s DPSK broadcast signals are used for downstream transmission. We employ a wavelength re-modulation for 2.5-Gb/s on-off keying (OOK) upstream signals to simplify the optical network unit as well as reduce the cost. Single-sideband (SSB) modulation format is utilized to eliminate the fading effect for downstream signals. The results show its prospect in future optical access network.

GMPLS protocol suite is unaware of optical signal physical impairments and quality of transmission. However, optical path computation and signaling nowadays requires to verify its practical feasibility considering the optical impairments (e.g. attenuation, PMD, etc) such that the end-to-end physical signals has an acceptable quality. In fact, current deployments of Wavelength Switched Optical Networks (WSON) implementations are subject to either transponder upgrade in bit rate or switching capability in network element, such that many wavelength paths cannot be any more considered pre-validated from the original network design phase. In this paper, the general problem of impairment-aware path computation is presented and then solutions based on extensions of the GMPLS signaling protocol are considered. Specifically, an overview is presented where different approaches for implementing Quality of Transmission (QoT) estimation and QoT measurements in transparent networks are outlined. In addition, techniques for exploiting sparse regeneration in translucent networks are illustrated. Numerical results show that the proposed schemes are effective in finding or designating QoT-validated paths in only a few set-up attempts when a fully transparent path is available. If the transparent path becomes unfeasible, the translucent approach is adopted showing how to optimally designate intermediate regenerators to satisfy the end-to-end QoT constraints.

We propose a novel RoF architecture for simultaneously realizing optical single sideband (SSB) millimeter-wave (mm-wave) signal generation and wavelength reuse for uplink connection. In the central office, the optical SSB signal with frequency-doubling is generated via proper dc-bias on an integrated dual-parallel Mazh-Zehnder modulator. In the base station, both the 2^nd order sidebands and partial central carrier of the generated optical SSB signal are beat to generate mm-wave signal that has double the frequency of the RF drive signal, while the other partial central carrier is remodulate with upstream data for uplink transmission.

We report on our ongoing research activities on integrated EPON and WLAN-based wireless mesh networks with a focus on reducing the CO₂ footprint and improving the bandwidth-efficient video transport of fiber-wireless (FiWi) access networks. Various power saving techniques and mechanisms for efficient video transport in FiWi access networks are discussed.

A novel method and its system design for controlling user's traffic in broadband access segments to enhance fairness among users are proposed and demonstrated. Recently, various new applications such as consumer generated media (e.g. YouTube) and peer-to-peer file sharing have been emerging in addition to the conventional applications such as E-mail and World Wide Web. Such novel applications have behaviors different from those of conventional applications in terms of traffic burstiness, and they tend to exhaust bandwidth for a certain period of time. Hence, there is a potential risk that the traffic of small numbers of specific users assumes bad influence on the traffic quality as well as on the experiences of other users. Such situation must be avoided from the standpoint of service fairness among the users. The proposed bandwidth control system utilizes QoS-related functions of existing heterogeneous access equipments, and provides a mechanism for maintaining bandwidth assignment based on each user's profile and history of usage. Control of the user traffic according to a bandwidth assignment policy is successfully demonstrated using a prototype system implemented in a testbed.

A global reference model covering next generation active and passive networks has been developed for techno-economic evaluations, and an extensive techno-economic analysis with a focus on CAPEX has been performed for 10G TDM PON and 1G AON - both capable of delivering 1Gbit/s to end-users. Two major cases have been considered: urban and rural at green field deployment. The results show that AON is less expensive than PON solution in urban case while in rural case 10G TDM PON is more competitive.

This paper investigated the influence of the waveband parameters on the number of ports of optical cross-connect (OXC) in waveband switching networks. The concept of waveband switching has been studied to decrease size of OXC when the number of wavelength increases, and the waveband parameters influence the size of OXC. We defined two waveband parameters; One is the number of path in a waveband and another is minimum number of the paths to group. The later waveband parameter means to allow several unused wavelength in a waveband. We evaluated the number input ports of OXC and the number of required wavelength with changing the parameters. The routing algorithm takes account of the delay of routes and of equalization of the number of wavelength in a link. Waveband path groups several wavelength paths with the same part of route in this simulation. Numerical experiments show that the wide bandwidth of a waveband saves the number of ports of OXC when the network has large traffic volume. On the other hand, if unused wavelength is allowed in a waveband, the number of port of OXC can be decreased, but the maximum number of wavelength in network is much required.

Presented in this paper is a dual routing engine-enabled optical network platform with multi-domains and multi-layers. Structure and key technologies of the platform are outlined. Experiments on it with 2 routing strategies are conducted, the results are discussed and the network scalability is evaluated.

There has been growing interest in transmitting synchronization information over Optical Transport Network (OTN). A novel scheme is proposed in the paper for this purpose. In order to support precise time synchronization information transfer over OTN, the proposed scheme designs the new overhead, equipment function architectures and interworking mechanism of synchronization message for OTN.

The convergence of EPON and WiMAX is one promising solution for Fiber Wireless access network, QoS is an important technical issue in this hybrid access network. We propose a novel QoS scheme of EPON and WiMAX integrated network based on unified QoS management which has been implemented and proved its effectiveness.

In this study, we investigate the dynamic connection provisioning problem in mixed-line-rate (MLR) optical networks. Fast heuristic algorithms are proposed for both fixed and tunable node architectures. Results show that our algorithm can significantly reduce the blocking probability and save the transceivers under tunable node architecture.

The process of computing routes that network traffic must follow throughout network has become much more complex in recent years. PCE (Path Computational Element) technology is emerging and gaining importance under the circumstances. In this paper, PCE architecture is outlined, and the impact of PCEs allocation decisions is discussed briefly. To track the problem of locating PCEs, an integer linear programming (ILP) model is presented to find the optimal PCEs allocation solution in multi-domain optical networks. The objective is to minimize average amount of time for sending a message to all nodes in the topology, i.e. message flooding cost. Then, two heuristics, LSPLP and TSPLP, are developed based on this model. Numerical results show that compared with traditional allocation strategies, the proposed algorithms can reduce the message flooding cost efficiently.

To compute the end-to-end diverse path in multi-domain networks is still a challenging topic puzzled both the network industry and the network academy. Although the existing Path Computation Element (PCE)-based simultaneous scheme performs minimum blocking rate, the computation complexity and communication overhead are high. In this paper, an enhanced PCE-based simultaneous scheme is proposed to decrease the computation complex and communication overhead. Analysis and simulation show the effectiveness of the proposed scheme.

In order to improve the wavelength utilization as well as the fairness of the light trail networks, we modified the FP MAC from the view point of weight balance by introducing a weight mode. The weight mode is composed of two factors, real-time factor and node activity ratio. Moreover, the weight mode is used as a bid by each LT node to compute the priority. Hence, the priority of the LT node is adjusted dynamically in every round and the MAC protocol with dynamic priority adjustment is entitled as DPA MAC. Simulation results show that the performances of DPA MAC protocol are much better than that of FP MAC protocol in terms of packet loss rate and activity percentile.

In order to resolve the P2P topology mismatch problem, a novel P2P service redirection scheme has been proposed by us and the scheme is fully described in reference. Furthermore, we have successfully implemented this mechanism in EPON system. Experimental results show that our scheme can effectively reduce core network traffic, and evidently improve clients' downloading rate.

This paper explores better physical layouts of the routing and control links within a multi-stage packet switched photonic network known as Data Vortex network architecture. For minimum signal interference and best synchronization, the proposed physical layouts allow for a non-crossing arrangement of the electrical control links while keeping the same simple optical routing paths patterns at specified routing levels. A general guidance is given for constructing such arrangements, and several examples are given in the discussion. The modified layouts allow for an easy optical implementation for the 3-D architecture, and they enable optimized the signal quality and effective synchronization of the physical systems.

An incremental capacity allocation with topology augmentation problem is investigated in this paper to maximize the backup path provisioned services in WDM mesh networks. To tackle the optimal design problem, an integer linear programming (ILP) formulation is presented. Numerical results show that all the services can be provisioned a backup path with little number of new links added to the existing topology.

With the development of large scale multi-layer and multi-domain optical networks, path computation becomes more complicated as complex policies and constraints are to be considered and dynamic routing becomes one of the key issues in GMPLS/ASON networks. A novel Dual Routing Engine Architecture in Multi-layer and multi-domain Scalable and Constraint-Aware Policy-Enabled optical networks (DREAMSCAPE), exploiting the advantages of both GMPLS control plane and Path Computation Element (PCE), is introduced to improve the performance of routing in multi-layer and multi-domain optical networks in this paper. In the architecture, the cooperation of Group Engine (GE) and Unit Engine (UE) makes it effective to optimize path computation especially under complex multi-constraints. The functional architectures of dual routing engines are described in the paper. Based on this novel architecture, a testbed with more than 1000 GMPLS-based control nodes has been built in our lab using virtual machine technology, and two path computation approaches have been implemented on the testbed. The latest results are experimentally demonstrated on the testbed, and some future research issues are presented in the conclusion.