Cycle-accurate evaluation of reconfigurable photonic networks-on-chip

There is little doubt that the most important limiting factors of the performance of next-generation Chip Multiprocessors (CMPs) will be the power efficiency and the available communication speed between cores. Photonic Networks-on-Chip (NoCs) have been suggested as a viable route to relieve the off- and on-chip interconnection bottleneck. Low-loss integrated optical waveguides can transport very high-speed data signals over longer distances as compared to on-chip electrical signaling. In addition, with the development of silicon microrings, photonic switches can be integrated to route signals in a data-transparent way. Although several photonic NoC proposals exist, their use is often limited to the communication of large data messages due to a relatively long set-up time of the photonic channels. In this work, we evaluate a reconfigurable photonic NoC in which the topology is adapted automatically (on a microsecond scale) to the evolving traffic situation by use of silicon microrings. To evaluate this system's performance, the proposed architecture has been implemented in a detailed full-system cycle-accurate simulator which is capable of generating realistic workloads and traffic patterns. In addition, a model was developed to estimate the power consumption of the full interconnection network which was compared with other photonic and electrical NoC solutions. We find that our proposed network architecture significantly lowers the average memory access latency (35% reduction) while only generating a modest increase in power consumption (20%), compared to a conventional concentrated mesh electrical signaling approach. When comparing our solution to high-speed circuit-switched photonic NoCs, long photonic channel set-up times can be tolerated which makes our approach directly applicable to current shared-memory CMPs

Architectural study of reconfigurable photonic networks-on-chip for multi-core processors

Photonic Networks-on-Chip (NoCs) have become a promising route to interconnect processor cores on chip multiprocessors (CMP) in a power efficient way. Although several photonic NoC proposals exist, their use is limited to the communication of large data messages due to a relatively long set-up time for the photonic channels. In this work, we evaluate a reconfigurable photonic NoC in which the topology is adapted automatically to the evolving traffic situation. This way, long photonic channel set-up times can be tolerated which makes our approach more compatible in the context of shared-memory CMPs

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

[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. IEEE Communications Magazine, 44(2), 15-22. doi:10.1109/mcom.2006.1593545Dhaini, A. R., Assi, C. M., Maier, M., & Shami, A. (2007). Dynamic Wavelength and Bandwidth Allocation in Hybrid TDM/WDM EPON Networks. Journal of Lightwave Technology, 25(1), 277-286. doi:10.1109/jlt.2006.886683Chihchung Chen, Chengkuo Lee, & Yen-Jyh Lai. (2003). Novel voa using in-plane reflective micromirror and off-axis light attenuation. IEEE Communications Magazine, 41(8), S16-S20. doi:10.1109/mcom.2003.122271

Low-power reconfigurable network architecture for on-chip photonic interconnects

Photonic Networks-On-Chip have emerged as a viable solution for interconnecting multicore computer architectures in a power-efficient manner. Current architectures focus on large messages, however, which are not compatible with the coherence traffic found on chip multiprocessor networks. In this paper, we introduce a reconfigurable optical interconnect in which the topology is adapted automatically to the evolving traffic situation. This allows a large fraction of the (short) coherence messages to use the optical links, making our technique a better match for CMP networks when compared to existing solutions. We also evaluate the performance and power efficiency of our architecture using an assumed physical implementation based on ultra-low power optical switching devices and under realistic traffic load conditions

Application specific photonic integrated circuits through generic integration, a novel paradigm in photonics

[EN] This paper reviews our recent work on integrating photonic devices and sub-systems onto a single photonic chip, by means of generic integration.This work has been partially funded through the Spanish Plan Nacional de I+D+i 2008-2011 project ”Coupled Resonator Optical Waveguide eNgineering (CROWN)” grant no. TEC2008-06145/ TEC, by the Generalitat Valenciana through project PROMETEO/2008/092 and by the EC FP6 contract no. 004525 ePIXnet. J.D. Doménech acknowledges the FPI research grant BES-2009-018381.Muñoz Muñoz, P.; Doménech Gómez, JD.; Artundo Martínez, I.; Habib, C.; Leijtens, X.; De Vries, T.; Robbins, D.... (2011). Application specific photonic integrated circuits through generic integration, a novel paradigm in photonics. Waves. 3:58-64. http://hdl.handle.net/10251/57675S5864

Cost forecasting of passive components for optical fiber network deployments

[EN] To analyze the costs of deploying any optical fiber network, it is critical to know the evolution of prices of its individual components in time. In this paper we investigate on the pricing and installation costs of several passive optical components, focusing as an example on optical fiber connectors, and present reliable data price trends for them. We then propose future costs based on parametric methods and the application of the extended learning curve model. The key contributions of this analysis are the accurate learning coefficients extracted for each type of optical component, ranging from 0.66 to 0.96 for fiber connectors or 0.88 for fiber cables, which can serve as valuable inputs to more complex, higher-level techno-economical models. Large price drops of 33% for splitters and 78% for attenuators have been also identified with these methods for the following years.This work was supported by the EC 7th Framework Program: Architectures for fLexible Photonic Home and Access networks (ALPHA), ICT 212 352.Artundo Martínez, I.; Tymecki, A.; Ortego, E.; Ortega Tamarit, B. (2011). Cost forecasting of passive components for optical fiber network deployments. Optical Fiber Technology. 17(3):218-226. https://doi.org/10.1016/j.yofte.2011.02.001S21822617

Reconfigurable networks-on-chip

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Track 2: ELECTRONICS & TELECOMMUNICATIONS PERFORMANCE EVALUATION OF LARGE RECONFIGURABLE INTERCONNECTS FOR MULTIPROCESSOR SYSTEMS

Communication has always been a limiting factor in making efficient computing architectures with large processor counts. Reconfigurable interconnects can help in this respect, since they can adapt the interprocessor network to the changing communication requirements imposed by the running application. In this paper, we present a performance evaluation of these reconfigurable interconnection networks in the context of shared-memory multiprocessor (SMP) machines. We look at the effects of architectural parameters such as reconfiguration speed and topological constraints, and analyze how these results scale up with higher processor counts. We find that for 16 processors connected in a torus topology, reconfigurable interconnects with switching speeds in the order of milliseconds can provide up to 20 % reduction in communication delay. For larger networks, up to 64 processors, the expected gain can rise up to 40%. This shows that reconfigurable networks can help in removing the communication bottleneck from future interconnection designs. 1