Timothy Girry Kale

Improving the Tor traffic distribution with circuit switching method

The Tor network has its user grown by thousands every year. The increasing number of users around the world makes Tor become one of the widely used privacy networks today. However, as the number of Tor user increases, the performance of Tor degrades badly due to traffic is not fairly distributed. As a result, the Tor network does not provide a better quality of communication for all its users. To improve these problems, we proposed a simple method of dynamic circuit switching on the Tor application level to distribute the bulk and light traffic on Tor. We calculated the fairness indexes of transferred bulk and light traffic to observe any improvement and, compared our method with the default entry onion router algorithm. Our experimental results show the proposed method improves the distribution of traffic and achieves fairness of throughputs for all Tor users.

Evaluation of dynamic circuit switching to reduce congestion in Tor

The Tor network is a widespread overlay anonymous network that is used by millions of users today. Tor focuses on improving the privacy of its users by routing their traffics through a series of onion routers that are located around the world. Since Tor operations mainly depend on volunteers who donated onion routers in the network, there are variances of capacities amongst different onion routers, which degrade the performances of Tor. In an effort to reduce the congestion problems in Tor, first we implemented control metrics to detect congestion on the entry OR. Second, we performed dynamic estimation of circuit congestion to select the best path in Tor. Third, we addressed the unfair distribution of bandwidth between the bulk and light traffics in Tor. We distributed the light and bulk traffics in Tor by having almost the same throughputs compared to default Tor multiplexing circuit approach. We use RTTs, circuit congestion and OR capacities as the main metrics to select the path. From our experimental analysis, we showed that our circuit switching method is effective to reduce the congestion problems in Tor.

Improving Consistency of Parallel Emulation for Multi-hop Wireless Ad-Hoc Network

When parallel and distribution processing is used for wireless network emulation, the results are different in case that each of the receiver nodes independently run the events without synchronizing among these events. In our previous study for the parallel wireless network emulation, we proposed a synchronizing method to get the same result of collision event among the terminals that receive the same frame over the wireless network. The frame has a seed of the random number to be used for an event execution at the receiver terminals within one hop. In addition, the information needed for the event execution is also previously shared among the receivers in order to get the same result. However, the effectiveness of our previous work is limited to one-hop wireless communication. In this paper, we extend our previous method to multi-hop wireless network environment with considering a hidden terminal and sharing parameters needed for the event execution. Our proposed method is evaluated with comparing our previous work and the original extendable mobile ad-hoc network emulator (EMANE).

Evaluating tor modified switching algorithm in the emulation environment

The Tor network is an open network that helps its users to defend against adversaries who performed traffic analysis and threatens the personal privacy and confidential security. Tor protects its users by preventing the sites they visit from revealing their physical location. As the number of Tor user increases, the performance of Tor degrades badly due to Tors scheduler is not fairly distributing the traffic in Tor. In this paper, we highlight the problems in Tor performance due to scheduling design of Tor, which degrades the web and bulk traffic performances that multiplexes on a single TCP connection. To solve these problems, this paper emphasis on applying a simple method of active circuit switching on Tor application level, in order to distribute the bulk and web traffics on different TCP connections when congestion is detected in the Tor network. We evaluate our modified switching algorithm with the other default schedulers in Tor, such as vanilla Tor and priority EWMA scheduler in a shadow wide deployment network emulator. The experimental results show that our switching technique considerably offers stable improvement of traffic performance for all the web and bulk traffics.