RDMA Transports in Datacenter Networks: Survey

Abstract

Remote Direct Memory Access (RDMA) has become an important building block of modern datacenter network (DCN) infrastructure given the merits of kernel bypass, zero memory copy techniques and low CPU overhead. However, the increasingly stringent performance requirements of both ultra-low latency and high throughput from the booming datacenter applications raise substantial challenges to the widespread adoption of RDMA in large-scale DCNs. This article identifies and discusses specific challenges facing RDMA deployment, including congestion control, multi-path transmission and scalability issues. We provide a comprehensive review of the efforts undertaken over the past decade to enhance RDMA performance, highlighting the key innovations of these RDMA transports. Furthermore, we explore the insights behind these RDMA transport schemes and outline the future research opportunities with the hope to inspire new interests and shed light on the following research in this field.