Evaluation of virtual private network impact on network performance

Abstract

The aim of the study is to investigate what impact the use of VPN has on network performance. An empirical investigation using quantitative research methods was carried out. Two sample scenarios were involved in the study: scenario without VPN and scenario with VPN. In both scenarios, three applications were used in turns, an HTTP, an FTP, and a CBR. FTP was configured to use window size and packet size, while CBR used connection rate and packet size. On the other side, the number of connection was the only parameter used for HTTP. These applications were injected in a 100 Mbps fixed link of an NS2 simulation environment. Throughput and delay averages were measured respectively for the two scenarios and values compared using Student’s t-test. While the TCP and HTTP throughputs were found decreasing, the UDP throughput was not affected by the presence of this VPN. Concerning the delay; the TCP, UDP and HTTP delay were found increasing.