Empirical performance analysis of anonymizing VoIP over The Onion Router (TOR) network

Abstract

Currently, Voice over Internet Protocol (VoIP) is replacing traditional telephone systems Public Switched Telephone Network (PSTN). Unlike PSTN, VoIP transfers data packets over the open network the Internet. It is possible to monitor data packets from any location connected to the Internet network; hence, it is necessary to consider security and privacy when implementing a VoIP system. However, due to the unpredictability of network connections and routes in the existing anonymous systems, adopting security and privacy in VoIP network reduces the Quality of Service (QoS). In this paper, Quality of Service of VoIP on an existing anonymous system - The Onion Router (TOR) is investigated. This research focuses on three QoS features, namely latency, jitter and packet loss. An acceptable quality call meets the QoS recommendation if its latency in VoIP is less than 400 ms, its jitter less than 30 ms and its packet loss less than 5%. This research investigates the QoS in two scenarios: TOR with 3 relays and TOR with 2 relays. The results of this research reveal that percentages of acceptable quality calls in both scenarios were less than 50% for 1% packet loss.