Abstract
Tor, an anonymity network formed by volunteer nodes, uses the estimated bandwidth of the nodes as a central feature of its path selection algorithm. The current load on nodes is not considered in this algorithm, however, and we observe that some nodes persist in being under-utilized or congested. This can degrade the network’s performance, discourage Tor adoption, and consequently reduce the size of Tor’s anonymity set. In an effort to reduce congestion and improve load balancing, we propose a congestion-aware path selection algorithm. Using latency as an indicator of congestion, clients use opportunistic and lightweight active measurements to evaluate the congestion state of nodes, and reject nodes that appear congested. Through experiments conducted on the live Tor network, we verify our hypothesis that clients can infer congestion using latency and show that congestion-aware path selection can improve performance.
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Wang, T., Bauer, K., Forero, C., Goldberg, I. (2012). Congestion-Aware Path Selection for Tor. In: Keromytis, A.D. (eds) Financial Cryptography and Data Security. FC 2012. Lecture Notes in Computer Science, vol 7397. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-32946-3_9
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