386 research outputs found

    Multi-Granular Optical Cross-Connect: Design, Analysis, and Demonstration

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    A fundamental issue in all-optical switching is to offer efficient and cost-effective transport services for a wide range of bandwidth granularities. This paper presents multi-granular optical cross-connect (MG-OXC) architectures that combine slow (ms regime) and fast (ns regime) switch elements, in order to support optical circuit switching (OCS), optical burst switching (OBS), and even optical packet switching (OPS). The MG-OXC architectures are designed to provide a cost-effective approach, while offering the flexibility and reconfigurability to deal with dynamic requirements of different applications. All proposed MG-OXC designs are analyzed and compared in terms of dimensionality, flexibility/reconfigurability, and scalability. Furthermore, node level simulations are conducted to evaluate the performance of MG-OXCs under different traffic regimes. Finally, the feasibility of the proposed architectures is demonstrated on an application-aware, multi-bit-rate (10 and 40 Gbps), end-to-end OBS testbed

    Modular expansion and reconfiguration of shufflenets in multi-star implementations.

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    by Philip Pak-tung To.Thesis (M.Phil.)--Chinese University of Hong Kong, 1994.Includes bibliographical references (leaves 57-60).Chapter 1 --- Introduction --- p.1Chapter 2 --- Modular Expansion of ShuffleNet --- p.8Chapter 2.1 --- Multi-Star Implementation of ShuffleNet --- p.10Chapter 2.2 --- Modular Expansion of ShuffleNet --- p.21Chapter 2.2.1 --- Expansion Phase 1 --- p.21Chapter 2.2.2 --- Subsequent Expansion Phases --- p.24Chapter 2.3 --- Discussions --- p.26Chapter 3 --- Reconfigurability of ShuffleNet in Multi-Star Implementation --- p.33Chapter 3.1 --- Reconfigurability of ShuffleNet --- p.34Chapter 3.1.1 --- Definitions --- p.34Chapter 3.1.2 --- Rearrangable Conditions --- p.35Chapter 3.1.3 --- Formal Representation --- p.38Chapter 3.2 --- Maximizing Network Reconfigurability --- p.40Chapter 3.2.1 --- Rules to maximize Tsc and Rsc --- p.41Chapter 3.2.2 --- Rules to Maximize Z --- p.42Chapter 3.3 --- Channels Assignment Algorithms --- p.43Chapter 3.3.1 --- Channels Assignment Algorithm for w = p --- p.45Chapter 3.3.2 --- Channels Assignment Algorithm for w = p. k --- p.46Chapter 3.3.3 --- Channels Assignment Algorithm for w=Mpk --- p.49Chapter 3.4 --- Discussions --- p.51Chapter 4 --- Conclusions --- p.5

    Wavelength reconfigurability for next generation optical access networks

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    Next generation optical access networks should not only increase the capacity but also be able to redistribute the capacity on the fly in order to manage larger variations in traffic patterns. Wavelength reconfigurability is the instrument to enable such capability of network-wide bandwidth redistribution since it allows dynamic sharing of both wavelengths and timeslots in WDM-TDM optical access networks. However, reconfigurability typically requires tunable lasers and tunable filters at the user side, resulting in cost-prohibitive optical network units (ONU). In this dissertation, I propose a novel concept named cyclic-linked flexibility to address the cost-prohibitive problem. By using the cyclic-linked flexibility, the ONU needs to switch only within a subset of two pre-planned wavelengths, however, the cyclic-linked structure of wavelengths allows free bandwidth to be shifted to any wavelength by a rearrangement process. Rearrangement algorithm are developed to demonstrate that the cyclic-linked flexibility performs close to the fully flexible network in terms of blocking probability, packet delay, and packet loss. Furthermore, the evaluation shows that the rearrangement process has a minimum impact to in-service ONUs. To realize the cyclic-linked flexibility, a family of four physical architectures is proposed. PRO-Access architecture is suitable for new deployments and disruptive upgrades in which the network reach is not longer than 20 km. WCL-Access architecture is suitable for metro-access merger with the reach up to 100 km. PSB-Access architecture is suitable to implement directly on power-splitter-based PON deployments, which allows coexistence with current technologies. The cyclically-linked protection architecture can be used with current and future PON standards when network protection is required

    On the Conditions that Justify Dynamic Reconfigurability in WDM-TDMA Optical Access Networks

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    [EN] In a passive optical network with a hybrid wavelength division multiplexing time division multiple-access scheme, implementing reconfigurable wavelength assignment is complex; hence the need to determine the conditions for which the capacity improvements justify requiring reconfigurability over adopting a more inexpensive fixed wavelength assignment. Fixed and reconfigurable approaches to wavelength assignment are modeled and evaluated under nonstationary traffic conditions. The performance improvement is obtained in terms of bit rate gain relative to the nominal bandwidth and depends on the number of wavelength channels as well as the magnitude of the load offered by the optical network units. In addition, frame delay and frame loss in relation to the bit rate performance are obtained for Pareto and exponentially distributed traffic. Simulations show that when introducing reconfigurability, typical peak bit rate gains with respect to the fixed case are 17%, and maxima of 175% are potentially possible when traffic demands are particularly uneven.This work was supported by the EC 7th Framework Program: Architectures for fLexible Photonic Home and Access networks (ALPHA), under contract ICT CP-IP 212 352, from the Generalitat of Valencia under contract ACOMP/2010/196. The authors thank the Performability Engineering Research Group (PERFORM) at the University of Illinois at Urbana-Champaign for developing the software tool Mobius.García Roger, D.; Artundo Martínez, I.; Ortega Tamarit, B. (2011). On the Conditions that Justify Dynamic Reconfigurability in WDM-TDMA Optical Access Networks. Journal of Optical Communications and Networking. 3(4):259-271. https://doi.org/10.1364/JOCN.3.000259S25927134A highly flexible and efficient passive optical network employing dynamic wavelength allocation. (2005). Journal of Lightwave Technology, 23(1), 277-286. doi:10.1109/jlt.2004.838811Maier, M., Herzog, M., & Reisslein, M. (2007). STARGATE: the next evolutionary step toward unleashing the potential of WDM EPONs [Topics in Optical Communications]. IEEE Communications Magazine, 45(5), 50-56. doi:10.1109/mcom.2007.358848Urban, P. J., Huiszoon, B., Roy, R., de Laat, M. M., Huijskens, F. M., Klein, E. J., … de Waardt, H. (2009). High-Bit-Rate Dynamically Reconfigurable WDM–TDM Access Network. Journal of Optical Communications and Networking, 1(2), A143. doi:10.1364/jocn.1.00a143Glatty, R., Guignard, P., & Chanclou, P. (2009). Fair Resource Distribution Within the Flexible WDMA/TDMA Optical Access Network Based on GPON Infrastructure. Journal of Optical Communications and Networking, 1(2), A17. doi:10.1364/jocn.1.000a17Roy, R., Manhoudt, G., & van Etten, W. (2008). Optical-router-based dynamically reconfigurable photonic access network. Journal of Optical Networking, 8(1), 51. doi:10.1364/jon.8.000051Koonen, T., Steenbergen, K., Janssen, F., & Wellen, J. (2001). Photonic Network Communications, 3(3), 297-306. doi:10.1023/a:1011411600793Homa, J., & Bala, K. (2008). ROADM Architectures and Their Enabling WSS Technology. IEEE Communications Magazine, 46(7), 150-154. doi:10.1109/mcom.2008.4557058Strasser, T., & Taylor, J. (2008). ROADMS Unlock the Edge of the Network. IEEE Communications Magazine, 46(7), 146-149. doi:10.1109/mcom.2008.4557057Leland, W. E., Taqqu, M. S., Willinger, W., & Wilson, D. V. (1994). On the self-similar nature of Ethernet traffic (extended version). IEEE/ACM Transactions on Networking, 2(1), 1-15. doi:10.1109/90.282603Kramer, G., Mukherjee, B., & Pesavento, G. (2002). Photonic Network Communications, 4(1), 89-107. doi:10.1023/a:1012959023043Skubic, B., Jiajia Chen, Ahmed, J., Wosinska, L., & Mukherjee, B. (2009). A comparison of dynamic bandwidth allocation for EPON, GPON, and next-generation TDM PON. IEEE Communications Magazine, 47(3), S40-S48. doi:10.1109/mcom.2009.4804388Papadimitriou, G. I., & Pomportsis, A. S. (1999). Self-adaptive TDMA protocols for WDM star networks: a learning-automata-based approach. IEEE Photonics Technology Letters, 11(10), 1322-1324. doi:10.1109/68.789731Linardakis, C., Leligou, H. C., Stavdas, A., & Angelopoulos, J. D. (2005). Using explicit reservations to arbitrate access to a metropolitan system of slotted interconnected rings combining TDMA and WDMA. Journal of Lightwave Technology, 23(4), 1576-1585. doi:10.1109/jlt.2005.844198Kanonakis, K., & Tomkos, I. (2010). Improving the efficiency of online upstream scheduling and wavelength assignment in hybrid WDM/TDMA EPON networks. IEEE Journal on Selected Areas in Communications, 28(6), 838-848. doi:10.1109/jsac.2010.100809McGarry, M. P., Reisslein, M., & Maier, M. (2006). WDM Ethernet passive optical networks. 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    AgileDCN:An Agile Reconfigurable Optical Data Center Network Architecture

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    This paper presents a detailed examination of a novel data center network (DCN) that can satisfy the high capacity and low latency requirements of modern cloud computing applications. This reconfigurable architecture called AgileDCN uses fast-switching optical components with a centralized control function and workload scheduler. By providing a highly flexible optical network fabric between server racks, very high network efficiencies can be achieved even under imbalanced loading patterns. Our simulation results show that, at high (70%) loads, TCP flow completion times in the AgileDCN are significantly lower than in an equivalent electronic leaf-spine network

    Quasi-passive optical infrastructure for future 5G wireless networks: pros and cons

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    In this paper, we study the applicability of the quasi-passive reconfigurable (QPAR) device, a special type of quasi-passive wavelength-selective switch with flexible power allocation properties and no power consumption in the steady state, to implement the concept of reconfigurable backhaul for 5G wireless networks. We first discuss the functionality of the QPAR node and its discrete component implementation, scalability, and performance. We present a novel multi-input QPAR structure and the pseudo-passive reconfigurable (PPAR) node, a device with the functionality of QPAR but that is pseudo-passive during steady-state operations. We then propose mesh and hierarchical back-haul network architectures for 5G based on the QPAR and PPAR nodes and discuss potential use cases. We compare the performance of a QPAR-based single-node architecture with state-of-the-art devices. We find that a QPAR node in a hierarchical network can reduce the average latency while extending the reach and quality of service of the network. However, due to the high insertion losses of the current QPAR design, some of these benefits are lost in practice. On the other hand, the PPAR node can realize the benefits practically and is the more energy-efficient solution for high reconfiguration frequencies, but the remote optical node will no longer be passive. In this paper, we discuss the potential benefits and issues with utilizing a QPAR in the optical infrastructure for 5G networks.This work has been funded by the Spanish project TIGRE5 CM (grant number S2013/ICE 2919), the EU H2020 5G Crosshaul project (grant number 671598), and the Australian Research Council’s Discovery Early Career Researcher Award (DECRA) funding scheme (project number DE150100924). The authors would also like to acknowledge the support of the Center for Integrated Systems, Stanford University, and Corning Incorporated. for the development of this work
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