The Experts below are selected from a list of 108 Experts worldwide ranked by ideXlab platform
José Duato - One of the best experts on this subject based on the ideXlab platform.
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towards an efficient Fat Tree like Topology
International Conference on Parallel Processing, 2012Co-Authors: Bermudez D Garzon, M.E. Gomez, Crispin Gomez, Pedro Lopez, José DuatoAbstract:Topology and routing algorithm are two key design parameters for interconnection networks. They highly define the performance achieved by the network, but also its complexity and cost. Many of the commodity interconnects for clusters are based on the Fat---Tree Topology, which allows both a rich interconnection among the nodes of the network and the use of adaptive routing. In this paper, we analyze how the routing algorithm affects the complexity of the switch, and considering this, we also propose and analyze some extensions of the Fat---Tree Topology to take advantage of the available hardware resources. We analyze not only the impact on performance of these extensions but also their influence over switch complexity, analyzing its cost.
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RUFT: Simplifying the Fat-Tree Topology
Parallel and Distributed Systems, 2008. ICPADS '08. 14th IEEE International Conference on, 2008Co-Authors: C Gomez, M.E. Gomez, F. Gilabert, P. López, José DuatoAbstract:The Fat-Tree is one of the most widely-used topologies by interconnection network manufacturers. Recently, a deterministic routing algorithm that optimally balances the network traffic in Fat--Trees was proposed. It can not only achieve almost the same performance than adaptive routing, but also outperforms it for some traffic patterns. Nevertheless, Fat-Trees require a high number of switches with a non-negligible wiring complexity. In this paper, we propose replacing the Fat-Tree by an unidirectional multistage interconnection network referred to as reduced unidirectional Fat-Tree (RUFT) that uses a a simplified version of the aforementioned deterministic routing algorithm. As a consequence, switch hardware is almost reduced to the half, decreasing, in this way, power consumption, arbitration complexity, switch size, and network cost. Evaluation results show that RUFT obtains lower latency than Fat-Tree for low and medium traffic loads. Furthermore, in large networks, it obtains almost the same throughput than the classical Fat-Tree.
N Calabretta - One of the best experts on this subject based on the ideXlab platform.
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numerical and experimental study of a high port density wdm optical packet switch architecture for data centers
Optics Express, 2013Co-Authors: S Di Lucente, Pueyo R Centelles, A Rohit, K A Williams, Harm J S Dorren, N CalabrettaAbstract:Data centers have to sustain the rapid growth of data traffic due to the increasing demand of bandwidth-hungry internet services. The current intra-data center Fat Tree Topology causes communication bottlenecks in the server interaction process, power-hungry O-E-O conversions that limit the minimum latency and the power efficiency of these systems. In this paper we numerically and experimentally investigate an optical packet switch architecture with modular structure and highly distributed control that allow configuration times in the order of nanoseconds. Numerical results indicate that the candidate architecture scaled over 4000 ports, provides an overall throughput over 50 Tb/s and a packet loss rate below 10−6 while assuring sub-microsecond latency. We present experimental results that demonstrate the feasibility of a 16x16 optical packet switch based on parallel 1x4 integrated optical cross-connect modules. Error-free operations can be achieved with 4 dB penalty while the overall energy consumption is of 66 pJ/b. Based on those results, we discuss feasibility to scale the architecture to a much larger port count.
Yohei Hasegawa - One of the best experts on this subject based on the ideXlab platform.
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torus Topology data center network based on optical packet agile circuit switching with intelligent flow management
Journal of Lightwave Technology, 2015Co-Authors: Kenichi Kitayama, Ryo Takahashi, Tatsushi Nakahara, Yuecai Huang, Yuki Yoshida, T Segawa, Salah Ibrahim, Y Suzaki, Masahiro Hayashitani, Yohei HasegawaAbstract:We review our work on an intra-data center (DC) network based on co-deployment of optical packet switching (OPS) and optical circuit switching (OCS), conducted within the framework of a five-year-long national R&D program in Japan (∼March 2016). For the starter, preceding works relevant to optical switching technologies in intra-DC networks are briefly reviewed. Next, we present the architecture of our torus-Topology OPS and agile OCS intra-DC network, together with a new flow management concept, where instantaneous optical path on-demand, so-called Express Path is established. Then, our hybrid optoelectronic packet router (HOPR), which handles 100 Gbps (25 Gbps × 4-wavelength) optical packets and its enabling device and sub-system technologies are presented. The HOPR aims at a high energy-efficiency of 0.09 [W/Gbps] and low-latency of 100 ns regime. Next, we provide the contention resolution strategies in the OPS and agile OCS network and present the performance analysis with the simulation results. It is followed by the discussions on the power consumption of intra-DC networks. We compare the power consumption and the throughput of a conventional Fat-Tree Topology with the N -dimensional torus Topology. Finally, for further power saving, we propose a new scheme, which shuts off HOPR buffers according to the server operation status.
S Di Lucente - One of the best experts on this subject based on the ideXlab platform.
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numerical and experimental study of a high port density wdm optical packet switch architecture for data centers
Optics Express, 2013Co-Authors: S Di Lucente, Pueyo R Centelles, A Rohit, K A Williams, Harm J S Dorren, N CalabrettaAbstract:Data centers have to sustain the rapid growth of data traffic due to the increasing demand of bandwidth-hungry internet services. The current intra-data center Fat Tree Topology causes communication bottlenecks in the server interaction process, power-hungry O-E-O conversions that limit the minimum latency and the power efficiency of these systems. In this paper we numerically and experimentally investigate an optical packet switch architecture with modular structure and highly distributed control that allow configuration times in the order of nanoseconds. Numerical results indicate that the candidate architecture scaled over 4000 ports, provides an overall throughput over 50 Tb/s and a packet loss rate below 10−6 while assuring sub-microsecond latency. We present experimental results that demonstrate the feasibility of a 16x16 optical packet switch based on parallel 1x4 integrated optical cross-connect modules. Error-free operations can be achieved with 4 dB penalty while the overall energy consumption is of 66 pJ/b. Based on those results, we discuss feasibility to scale the architecture to a much larger port count.
Kenichi Kitayama - One of the best experts on this subject based on the ideXlab platform.
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torus Topology data center network based on optical packet agile circuit switching with intelligent flow management
Journal of Lightwave Technology, 2015Co-Authors: Kenichi Kitayama, Ryo Takahashi, Tatsushi Nakahara, Yuecai Huang, Yuki Yoshida, T Segawa, Salah Ibrahim, Y Suzaki, Masahiro Hayashitani, Yohei HasegawaAbstract:We review our work on an intra-data center (DC) network based on co-deployment of optical packet switching (OPS) and optical circuit switching (OCS), conducted within the framework of a five-year-long national R&D program in Japan (∼March 2016). For the starter, preceding works relevant to optical switching technologies in intra-DC networks are briefly reviewed. Next, we present the architecture of our torus-Topology OPS and agile OCS intra-DC network, together with a new flow management concept, where instantaneous optical path on-demand, so-called Express Path is established. Then, our hybrid optoelectronic packet router (HOPR), which handles 100 Gbps (25 Gbps × 4-wavelength) optical packets and its enabling device and sub-system technologies are presented. The HOPR aims at a high energy-efficiency of 0.09 [W/Gbps] and low-latency of 100 ns regime. Next, we provide the contention resolution strategies in the OPS and agile OCS network and present the performance analysis with the simulation results. It is followed by the discussions on the power consumption of intra-DC networks. We compare the power consumption and the throughput of a conventional Fat-Tree Topology with the N -dimensional torus Topology. Finally, for further power saving, we propose a new scheme, which shuts off HOPR buffers according to the server operation status.