More and more latency-sensitive services and applications are being deployed into the data center. Performance can be limited by the high latency of the network interconnect. Because the conventional network stack is designed not only for LAN, but also for WAN, it carries a great amount of redundancy that is not required in a data center network. This paper introduces the concept of a three-layer protocol stack that can fulfill the exact demands of data center network communications. The detailed design and implementation of the first layer of the stack, which we call RIFL, is presented. A novel low latency in-band hop-by-hop re-transmission protocol is proposed and adopted in RIFL, which guarantees lossless transmission in a data center environment. Experimental results show that RIFL achieves 110 nanoseconds point-to-point latency on 10-meter Active Optical Cables, at a line rate of 112 Gbps. RIFL is a multi-lane protocol with scalable throughput up to multi-hundred gigabits per second. It can be the enabler of low latency, high throughput, flexible, scalable, and lossless data center networks.

翻译：越来越多的延迟敏感型服务和应用被部署到数据中心中。网络互连的高延迟可能会限制性能。由于传统网络协议栈不仅是为局域网设计的，也适用于广域网，因此它包含了数据中心网络中不需要的大量冗余。本文引入了一种三层协议栈的概念，能够满足数据中心网络通信的精确需求。我们提出了该协议栈第一层（称为RIFL）的详细设计与实现。在RIFL中采用了一种新型低延迟带内逐跳重传协议，该协议保证了数据中心环境下的无损传输。实验结果表明，RIFL在112 Gbps的线路速率下，通过10米有源光缆实现了110纳秒的点对点延迟。RIFL是一种多通道协议，其可扩展吞吐量可达数百吉比特每秒。它能够为实现低延迟、高吞吐、灵活、可扩展且无损的数据中心网络提供支持。