Nagios TCP Degradation Detection Plugin

This Nagios plugin estimates the TCP traffic performance degradation from coarse link utilization traces, such as those obtainable by SNMP. TCP adapts its transmission rate to the available bandwidth and the performance is degraded before achieving the 100% link occupancy. This plugin is based on the method described in [1] and M/G/R processor sharing model to estimate TCP performance degradation from the analysis of the link utilization variance (it normally increases as the mean link-utilization increases but starts to decrease when the link performance is degraded). Thus, it allows detecting TCP performance degradation perceived by the users before plateaus appear in occupancy graphs, with no active measures, nor fine grained or complex monitoring.

[1] K. Ishibashi, R. Kawahara, T. Asaka, M. Aida, S. Ono, and S. Asano, “Detection of TCP Performance Degradation Using Link Utilization Statistics,” IEICE Trans. Comm., vol. E89-B, no. 1, pp. 47-56, Jan. 2006.