Xue Xuwei, Nakamura Fumi, Prifti Kristif, Pan Bitao, Yan Fulong, Wang Fu, Guo Xiaotao, Tsuda Hiroyuki, Calabretta Nicola
Opt Express. 2020 Mar 16;28(6):8949-8958. doi: 10.1364/OE.388759.
Optical switching techniques featuring the fast and large capacity have the potential to enable low latency and high throughput optical data center networks (DCN) to afford the rapid increasing of traffic-boosted applications. Flexibility of the DCN is of key importance to provide adaptive and dynamic bandwidth to handle the variable traffic patterns generated by the heterogeneous applications while optimizing the network resources. Aiming at providing the flexible bandwidth for optical DCNs, we propose and experimentally investigate a software-defined networking (SDN) enabled reconfigurable optical DCN architecture based on novel optical top of rack (OToR) switch exploiting photonic-integrated wavelength selective switch. Experimental results show that the optical bandwidth per link can be automatically reallocated under the management of the deployed SDN control plane according to the variable traffic patterns. With respect to the network with inflexible interconnections, the average packet loss of the reconfigurable DCN decreases 1 order of magnitude and the server-to-server latency performance improves of 42.2%. Scalability investigation illustrates limited (11.7%) performance degradation as the reconfigurable network scale from 2560 to 40960 servers. Both the numerical and experimental assessments validate the proposed DCN with reconfigurable bandwidth feature and lower latency variations with respect to the inflexible DCNs.
具有快速和大容量特点的光交换技术有潜力使低延迟和高吞吐量的光数据中心网络（DCN）能够适应流量增长迅速的应用程序的快速增长。DCN的灵活性对于提供自适应和动态带宽以处理异构应用程序产生的可变流量模式同时优化网络资源至关重要。为了给光DCN提供灵活的带宽，我们提出并通过实验研究了一种基于新型光机架顶（OToR）交换机的软件定义网络（SDN）支持的可重构光DCN架构，该交换机利用光子集成波长选择开关。实验结果表明，在已部署的SDN控制平面的管理下，每个链路的光带宽可以根据可变流量模式自动重新分配。对于互连不灵活的网络，可重构DCN的平均丢包率降低了1个数量级，服务器到服务器的延迟性能提高了42.2%。可扩展性研究表明，当可重构网络规模从2560个服务器扩展到40960个服务器时，性能下降有限（11.7%）。数值和实验评估都验证了所提出的具有可重构带宽特性和相对于不灵活DCN更低延迟变化的DCN。
