Non-intrusive IP Network Performance Monitoring for TCP Flows |
The expansion of the Internet in the past two decades has led to a large amount of traffic being carried over IP (Internet Protocol) networks, most of which is due to web browsing. Unfortunately, the Internet revolution was not accompanied by an improvement in monitoring. Until recently, the main problem that affects TCP (Transmission Control Protocol) performance was considered to be the available bandwidth and, in turn, bandwidth was less of an issue when compared to network availability. This paper presents a method that allows offline, single point, non-intrusive performance measurement for TCP connections. The method avoids all the limitations of present monitoring solutions, i.e. intrusive and / or complex, and offers in-depth information about the performance parameters. This is a first step in defining, evaluating and measuring network Quality of Service for TCP transfers. Test results show that the method is correct for measuring throughput and has an accuracy greater than 95% when determining RTT (Round Trip Time) values, but may have errors of up to 30% when estimating packet loss, due to uncertainty in determining certain events and to differences between various TCP implementations.
Ghita BV, Lines BL, Furnell SM, Ifeachor E