In this paper we present results of experimental work using machine learning techniques to rapidly identify Skype traffic. We show that Skype traffic can be identified by observing 5 seconds of a Skype traffic flow, with recall and precision better than 98%. We found the most effective features for classification were characteristic packet lengths less than 80 bytes, statistics of packet lengths greater than 80 bytes and inter-packet arrival times. Our classifiers do not rely on observing any particular part of a flow. We also report on the performance of classifiers built using combinations of two of these features and of each feature in isolation. Categories and Subject Descriptors C.2.3 [Network Operations]: Network Monitoring, Public Networks General Terms Algorithms, Measurement, Experimentation Keywords Skype, Traffic classification, Machine learning
Philip Branch, Amiel Heyde, Grenville J. Armitage