The Path Less Travelled: Overcoming Tor’s Bottlenecks with Traffic Splitting

Mashael AlSabah, Kevin Bauer, Mohammad Tariq Elahi, Ian Goldberg

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract / Description of output

Tor is the most popular low-latency anonymity network for enhancing ordinary users’ online privacy and resisting censorship. While it has grown in popularity, Tor has a variety of performance problems that result in poor quality of service, a strong disincentive to use the system, and weaker anonymity properties for all users. We observe that one reason why Tor is slow is due to low-bandwidth volunteer-operated routers. When clients use a low-bandwidth router, their throughput is limited by the capacity of the slowest node.

With the introduction of bridges—unadvertised Tor routers that provide Tor access to users within censored regimes like China—low-bandwidth Tor routers are becoming more common and essential to Tor’s ability to resist censorship. In this paper, we present Conflux, a dynamic traffic-splitting approach that assigns traffic to an overlay path based on its measured latency. Because it enhances the load-balancing properties of the network, Conflux considerably increases performance for clients using low-bandwidth bridges. Moreover, Conflux significantly improves the experience of users who watch streaming videos online.

Through live measurements and a whole-network evaluation conducted on a scalable network emulator, we show that our approach offers an improvement of approximately 30% in expected download time for web browsers who use Tor bridges and for streaming application users. We also show that Conflux introduces only slight tradeoffs between users’ anonymity and performance.
Original languageEnglish
Title of host publicationProceedings on the 13th International Symposium of Privacy Enhancing Technologies
Place of PublicationBloomington, IN, USA
PublisherSpringer Berlin Heidelberg
Number of pages21
ISBN (Electronic)978-3-642-39077-7
ISBN (Print)978-3-642-39076-0
Publication statusPublished - 2013
Event13th Privacy Enhancing Technologies Symposium - Bloomington, IN, United States
Duration: 10 Jul 201312 Jul 2013


Conference13th Privacy Enhancing Technologies Symposium
Abbreviated titlePETS 2013
Country/TerritoryUnited States
CityBloomington, IN
Internet address


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