RIFL: A Reliable Link Layer Network Protocol for Data Center Communication

TL;DR

RIFL is a new low-latency, lossless link layer protocol designed specifically for data center networks, achieving ultra-fast communication with high scalability and throughput.

Contribution

This paper introduces RIFL, a novel link layer protocol with in-band hop-by-hop retransmission, optimized for data center environments, reducing latency and increasing throughput.

Findings

Achieves 110 ns latency on 10-meter optical cables

Supports scalable throughput up to hundreds of Gbps

Guarantees lossless transmission with in-band retransmission

Abstract

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.