Saving Private WAN: Using Internet Paths to Offload WAN Traffic in Conferencing Services

TL;DR

This paper investigates offloading video conferencing traffic to the Internet to reduce WAN costs, demonstrating that Internet paths can be as good as or better than private WANs in many regions, and introduces systems that achieve significant cost savings.

Contribution

It provides a large-scale measurement study, a live system implementation, and a research prototype for optimizing traffic offloading in conferencing services.

Findings

Internet paths perform comparably or better than private WANs in key regions.

Titan system reduces WAN bandwidth peaks by up to 61%.

Titan-Next optimally assigns server and routing options for cost efficiency.

Abstract

Large-scale video conferencing services incur significant network cost while serving surging global demands. Our work systematically explores the opportunity to offload a fraction of this traffic to the Internet, a cheaper routing option offered already by cloud providers, from WAN without drop in application performance. First, with a large-scale latency measurement study with 3.5 million data points per day spanning 241K source cities and 21 data centers across the globe, we demonstrate that Internet paths perform comparable to or better than the private WAN for parts of the world (e.g., Europe and North America). Next, we present Titan, a live (12+ months) production system that carefully moves a fraction of the conferencing traffic to the Internet using the above observation. Finally, we propose Titan-Next, a research prototype that jointly assigns the conferencing server and routing option (Internet or WAN) for individual calls. With 5 weeks of production data, we show Titan-Next reduces the sum of peak bandwidth on WAN links that defines the operational network cost by up to 61% compared to state-of-the-art baselines. We will open-source parts of the measurement data.