Congestion Control Mechanisms for Inter-Datacenter Networks

The Hong Kong University of Science and Technology
Department of Computer Science and Engineering


PhD Thesis Defence


Title: "Congestion Control Mechanisms for Inter-Datacenter Networks"

By

Mr. Gaoxiong ZENG


Abstract

Applications running in geographically distributed setting are becoming 
prevalent. Large-scale online services often share or replicate their data into 
multiple data centers (DCs) in different geographic regions. Driven by the data 
communication need of these applications, inter-datacenter network (IDN) is 
getting increasingly important.

However, we find congestion control for inter-datacenter networks quite 
challenging. Firstly, the inter-datacenter communication involves both data 
center networks (DCNs) and wide-area networks (WANs) connecting multiple data 
centers. Such a network environment presents quite heterogeneous 
characteristics (e.g., buffer depths, RTTs). Existing congestion control 
mechanisms consider either DCN or WAN congestion, while not simultaneously 
capturing the degree of congestion for both.

Secondly, to reduce evolution cost and improve flexibility, large enterprises 
have been building and deploying their wide-area routers based on 
shallow-buffered switching chips. However, with legacy congestion control 
mechanisms (e.g., TCP Cubic), shallow buffer can easily get overwhelmed by 
large BDP (bandwidth-delay product) wide-area traffic, leading to high packet 
losses and degraded throughput.

This thesis describes my research efforts on optimizing congestion control 
mechanisms for the inter-datacenter networks. First, we design GEMINI — a 
practical congestion control mechanism that simultaneously handles congestions 
both in DCN andWAN. Second, we present FlashPass — a proactive congestion 
control mechanism that achieves near zero loss without degrading throughput 
under the shallow-buffered WAN. Extensive evaluation shows their superior 
performance over existing congestion control mechanisms.


Date:			Friday, 28 January 2022

Time:			2:00pm - 4:00pm

Zoom Meeting: 
https://hkust.zoom.us/j/98137126553?pwd=eEFnU3JLM0QwMG56SzlOMUVBcnlSdz09

Chairperson:		Prof. Yongshun CAI (SOSC)

Committee Members:	Prof. Kai CHEN (Supervisor)
 			Prof. Brahim BENSAOU
 			Prof. Qiong LUO
 			Prof. Jiang XU (ECE)
 			Prof. Hong XU (CUHK)


**** ALL are Welcome ****