Battle for Bandwidth: On the Deployability of New Congestion Control Algorithms
Content
Speaker: Ranysha Ware (Carnegie Mellon University)
Abstract
Congestion control algorithms (CCAs) are critical for the stability of the Internet: ensuring that users can fairly and efficiently share the network. With the initial deployment of CCAs on the Internet in the late 1980s, we had nice guarantees about fairness: if everyone used the same algorithm we could all share the network fairly. However, over the past 30 years, researchers and Internet content providers have proposed and deployed dozens of new CCAs designed to keep up with the growing demands of faster networks, diverse applications, and mobile users. In this talk, I present my thesis work on studying the implications of heterogeneity in CCAs on the Internet today. I present a model of Google’s new CCA, BBRv1, and prove that it can be very unfair to legacy loss-based algorithms, an alarming finding given the widespread deployment of BBRv1. Consequently, I argue that the methodology for determining if a new CCA is safe to deploy on the Internet today is fundamentally broken. I propose a new metric called harm, for measuring the impact a new CCA has on the performance of already deployed CCAs. I also propose a new tool called HarmGen that can efficiently evaluate interactions between heterogeneous CCAs. Lastly, I look towards the future–I discuss the implications of growing heterogeneity in CCAs and propose new approaches for evaluating new CCAs and their employability.
Bio
Ranysha Ware is a Teaching Postdoctoral Fellow at Carnegie Mellon University teaching introductory computer science courses. Outside of her passion for effective and inclusive teaching, her interests are in the measurement and evaluation of networked systems. Much of her research focuses on building better tools to understand and evaluate modern congestion control algorithms. Dr. Ware has received numerous awards, including the IRTF Applied Networking Research Prize, a Facebook Emerging Scholars Award, and a National GEM Consortium PhD Fellowship.
A pizza lunch for attendees will be available at 12:00 p.m. in CS 150.