Abstract:
One of the main obstacles that impede further expansion of Tor, the most popular anonymous communication system, is its large performance variance. The problem becomes wo...Show MoreMetadata
Abstract:
One of the main obstacles that impede further expansion of Tor, the most popular anonymous communication system, is its large performance variance. The problem becomes worse when bandwidth-intensive applications, such as video streaming, contend with latency-sensitive applications, such as web browsing, for the scarce resources. Most of the existing solutions involve circuit-scheduling techniques to prioritize interactive traffic over bulk traffic or to completely throttle traffic of bandwidth-intensive applications. However, these approaches not only rely on accurate detection of traffic types but also adopt detection strategies that are easy to game. In this paper, we propose a different approach by exploring new capabilities of Tor to support bulk data transfers without degrading the performance of interactive traffic. Based on our observations that a large portion of low-bandwidth relays are under-utilized, we develop a multi-path Tor (mTor) routing algorithm to cater to bandwidth-intensive applications by constructing multiple circuits across low-bandwidth Tor relays. We present a self-adaptive “pulling” scheduling technique to dynamically allocate cells across multiple circuits, and an active congestion detection scheme to prevent slow circuits from becoming a bottleneck of the entire tunnel. Based on the results from experiments on the live Tor network and simulations over the Shadow simulator [1], we conclude that mTor not only achieves a desirable performance for bandwidth-intensive applications by utilizing multiple low-bandwidth relays, but also benefits latency-sensitive applications by reducing the load on high-bandwidth relays.
Date of Conference: 28-30 September 2015
Date Added to IEEE Xplore: 07 December 2015
Electronic ISBN:978-1-4673-7876-5