Never Been KIST: Tor’s Congestion Management Blossoms with Kernel-Informed Socket Transport - CORE CORE Search Search Services Access to raw data API Dataset FastSync Content discovery Recommender Discovery Managing content Repository dashboard Support FAQs About About CORE Blog Contact us Never Been KIST: Tor’s Congestion Management Blossoms with Kernel-Informed Socket Transport By Rob Jansen, John Geddes, Chris Wacek, Micah Sherr and Paul Syverson Abstract Tor’s growing popularity and user diversity has re-sulted in network performance problems that are not well understood. A large body of work has attempted to solve these problems without a complete understand-ing of where congestion occurs in Tor. In this paper, we first study congestion in Tor at individual relays as well as along the entire end-to-end Tor path and find that congestion occurs almost exclusively in egress ker-nel socket buffers. We then analyze Tor’s socket interac-tions and discover two major issues affecting congestion: Tor writes sockets sequentially, and Tor writes as much as possible to each socket. We thus design, implement, and test KIST: a new socket management algorithm that uses real-time kernel information to dynamically com-pute the amount to write to each socket while consider-ing all writable circuits when scheduling new cells. We find that, in the medians, KIST reduces circuit conges-tion by over 30 percent, reduces network latency by 18 percent, and increases network throughput by nearly 10 percent. We analyze the security of KIST and find an ac-ceptable performance and security trade-off, as it does not significantly affect the outcome of well-known la-tency and throughput attacks. While our focus is Tor, our techniques and observations should help analyze and improve overlay and application performance, both for security applications and in general. Year: 2015 OAI identifier: oai:CiteSeerX.psu:10.1.1.697.9791 Provided by: CiteSeerX Download PDF: Sorry, we are unable to provide the full text but you may find it at the following location(s): http://freehaven.net/anonbib/c... (external link) http://freehaven.net/anonbib/c... (external link) http://citeseerx.ist.psu.edu/v... (external link) Suggested articles To submit an update or takedown request for this paper, please submit an Update/Correction/Removal Request. Useful links Blog Services About CORE Contact us Cookies Privacy notice Writing about CORE? Discover our research outputs and cite our work. CORE is a not-for-profit service delivered by the Open University and Jisc.
