Can We Trust ICMP Measurements?
Stefan Birrer, Fabián E. Bustamante and Yan Chen
Tech. Report NWU-CS-04-48, Department of Computer Science, Northwestern University, 2004.
Department of Computer Science
Evanston, IL 60201, USA
ICMP-based measurements (e.g. ping) are often criticized as un-representative of the applications' experienced performance, as applications are based on TCP/UDP protocols and there is a well-accepted conjecture that routers are often configured to treat ICMP differently from TCP and UDP.
However, to the best of our knowledge, this assumption has not been validated. With this in mind, we conducted extensive Internet end-to-end path measurements of these three protocols, spanning over 90 sites (from both commercial and academic networks), over 6,000 paths and more than 28 million probes in PlanetLab during two weeks.
Our results show that ICMP performance is a good estimator for TCP/UDP performance for the majority of the paths. However for nearly 0.5% of the paths, we found persistent RTT differences between UDP and ICMP greater than 50%, while for TCP the difference exceeds 10% for 0.27% of the paths. Thus, although ICMP-based measurements can be trusted as predictors of TCP/UDP performance, distributed systems and network researchers should be aware of some scenarios where these measurements will be heavily misleading; this paper also provides some hints that can help in identifying those situations.