Optical switching techniques have the potential to enable the optical data center network (DCN) interconnections providing high capacity and fast switching capabilities, overcoming thus the bandwidth and latency bottleneck of present electrical switch-based multi-tiered DCNs. The rapid growth of multi-tenant applications with heterogeneous traffic require specialized quality of service (QoS) in terms of packet loss and latency to the DCN infrastructure. Slicing the DCNs into dedicated pieces according to the deployed applications, differentiated QoS, and high resource utilization can be provided. However, slicing the optical DCNs still needs to be investigated because the Software-defined Networking (SDN) technique is developed for the electrical networks, not fully supporting the properties of the optical network. Additionally, Network Slices (NS) need to be automatically provisioned and reconfigured, to provide flexible slice interconnections in support of the multi-tenant applications to be deployed. In this article, we propose and experimentally assess the automatic and flexible NSs configurations of optical OPSquare DCN controlled and orchestrated by an extended SDN control plane for multi-tenant applications with differentiated QoS provisioning. Optical Flow Control (OFC) protocol has been developed to prevent packet losses at switch sides caused by packet contentions. The extended OpenFlow (OF) protocol of SDN is deployed as well in support of the optical switching characteristics. Based on the collected resource topology of data plane, the optical network slices can be dynamically provisioned and automatically reconfigured by the SDN control plane. Meanwhile, experimental results validate that the priority assignment of application flows supplies dynamic QoS performance to various slices running applications with specific requirements in terms of packet loss and transmission latency. In addition, the capability of exposing traffic statistics information of data plane to SDN control plane enables the implementation of load balancing algorithms further improving the network performance with high QoS. No packet loss and less than 4.8 μs server-to-server latency can be guaranteed for the sliced network with highest priority at a load of 0.5.

中文翻译：

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SDN 控制和编排的 OPSquare DCN 支持具有差异化 QoS 配置的自动网络切片

光交换技术有可能使光数据中心网络 (DCN) 互连提供高容量和快速交换能力，从而克服当前基于电交换的多层 DCN 的带宽和延迟瓶颈。具有异构流量的多租户应用程序的快速增长需要在数据包丢失和 DCN 基础设施延迟方面的专门服务质量 (QoS)。可以根据部署的应用将 DCN 切片成专用的片段，提供差异化​​的 QoS 和高资源利用率。然而，由于软件定义网络 (SDN) 技术是为电网络开发的，因此仍需要对光 DCN 进行切片，并不能完全支持光网络的特性。此外，网络切片（NS）需要自动配置和重新配置，以提供灵活的切片互连以支持要部署的多租户应用程序。在本文中，我们提出并通过实验评估了由扩展 SDN 控制平面控制和编排的光学 OPSquare DCN 的自动和灵活的 NS 配置，用于具有差异化 QoS 配置的多租户应用程序。已开发出光流控制 (OFC) 协议以防止由于数据包争用而导致交换机侧的数据包丢失。SDN 的扩展 OpenFlow (OF) 协议也被部署以支持光交换特性。基于采集到的数据平面资源拓扑，光网络切片可以由SDN控制平面动态提供和自动重新配置。同时，实验结果验证了应用程序流的优先级分配为运行应用程序的各种切片提供了动态 QoS 性能，这些应用程序在数据包丢失和传输延迟方面具有特定要求。此外，将数据平面的流量统计信息暴露给SDN控制平面的能力，可以实现负载均衡算法，进一步提升网络性能，高QoS。对于负载为0.5的最高优先级的切片网络，可以保证不丢包和小于4.8 μs的服务器到服务器延迟。将数据平面的流量统计信息暴露给SDN控制平面的能力，可以实现负载均衡算法，进一步提升网络性能，高QoS。在负载为0.5时，最高优先级的切片网络可以保证不丢包和小于4.8 μs的服务器到服务器延迟。将数据平面的流量统计信息暴露给SDN控制平面的能力，可以实现负载均衡算法，进一步提升网络性能，高QoS。对于负载为0.5的最高优先级的切片网络，可以保证不丢包和小于4.8 μs的服务器到服务器延迟。