Harmonia: Explicit Congestion Notification and Credit-Reservation Transport Converged Congestion Control in Datacenters  

作　　者：Ding-Huang Hu De-Zun Dong Yang Bai Shan Huang Ze-Jia Zhou Zi-Hao Wei Xiang-Ke Liao 

机构地区：[1]College of Computer Science and Technology,National University of Defense Technology,Changsha 410073,China

出　　处：《Journal of Computer Science & Technology》2021年第5期1071-1086,共16页计算机科学技术学报（英文版）

基　　金：supported by the National Key Research and Development Program of China under Grant No.2018YFB0204300;the National Postdoctoral Program for Innovative Talents under Grant No.BX20190091;Excellent Youth Foundation of Hunan Province(De-Zun Dong).

摘　　要：Bursty traffic and thousands of concurrent flows incur inevitable network congestion in datacenter networks(DCNs)and then affect the overall performance.Various transport protocols are developed to mitigate the network congestion,including reactive and proactive protocols.Reactive schemes use different congestion signals,such as explicit congestion notification(ECN)and round trip time(RTT),to handle the network congestion after congestion arises.However,with the growth of scale and link speed in datacenters,reactive schemes encounter a significant problem of slow responding to congestion.On the contrary,proactive protocols(e.g.,credit-reservation protocols)are designed to avoid congestion before it occurs,and they have the advantages of zero data loss,fast convergence and low buffer occupancy.But credit-reservation protocols have not been widely deployed in current DCNs(e.g.,Microsoft,Amazon),which mainly deploy ECN-based protocols,such as data center transport control protocol(DCTCP)and data center quantized congestion notification(DCQCN).And in an actual deployment scenario,it is hard to guarantee one protocol to be deployed in every server at one time.When credit-reservation protocol is deployed to DCNs step by step,the network will be converted to multi-protocol state and will face the following fundamental challenges:1)unfairness,2)high buffer occupancy,and 3)heavy tail latency.Therefore,we propose Harmonia,aiming for converging ECN-based and credit-reservation protocols to fairness with minimal modification.To the best of our knowledge,Harmonia is the first to address the trouble of harmonizing proactive and reactive congestion control.Targeting the common ECN-based protocols-DCTCP and DCQCN,Harmonia leverages forward ECN and RTT to deliver real-time congestion information and redefines feedback control.After the evaluation,the results show that Harmonia effectively solves the unfair link allocation,eliminating the timeouts and addressing the buffer overflow.

关 键 词：DATACENTER credit-reservation protocol ECN-based(explicit congestion notification based)protocol multiprotocol converging 

分 类 号：TP31[自动化与计算机技术—计算机软件与理论]