基于FPGA的低延迟TCP协议栈实现

Design and implementation of low latency TCP stack on FPGA

TCP/IP协议作为互联网最常用的通信协议,提供了可靠的数据传输、有序的报文交付和流量控制。然而,这些通信特性也随之带来了复杂性和高延迟的代价。虽然对于一些互联网应用程序来说,延迟并不是关键问题,但对于数据中心等对延迟敏感的用户来说,低延迟通信是最为关键的需求。设计了一种基于FPGA的TCP协议栈,通过改进TCP握手机制,减少了握手过程中的往返时间。对传统TCP协议栈的改动很小且保证了TCP协议的完备和可靠。实验表明与同样基于FPGA的TCP硬件协议栈相比,通信延迟上的性能最大提升可达44.7%。与基于高性能网络测试仪平台的软件协议栈相比,平均提升可达81.7%。

TCP/IP is the most popular protocol used in Internet.The protocol provides the reliable data transmission,in-order delivery and control flow.However,it is this functionality that brings the price of complexity and latency.While for the Internet application the latency issue is not so critical,it is intolerable for latency-sensitive users such as data center.In this paper,we present a TCP offload engine running on FPGA for data center applications.This paper designs a TCP protocol stack based on FPGA,which reduces the round-trip time during the handshake process by improving the TCP handshake mechanism.The traditional TCP protocol stack is modified slightly and the TCP protocol is complete and reliable.Experiments show that the maximum performance improvement on communication latency is 44.7%compared with the same TCP hardware stack based on FPGA.Compared with the software protocol stack based on the high performance network tester platform,the average improvement is 81.7%.