On the processing time for detection of Skype traffic

The last few years have witnessed VoIP applications gaining a tremendous popularity and Skype, in particular, is leading this continuous expansion. Unfortunately, Skype follows a closed source and proprietary design, and typically uses encryption mechanisms, making it very difficult to identify its presence from a traffic aggregate. Several algorithms and approaches have been proposed to perform such task with promising results in terms of accuracy. However, such approaches typically require significant computation resources and it is unlikely that they can be deployed in nowadays high-speed networks. In this light, this paper focuses on cutting the processing cost of algorithms to detect Skype traffic. We have conveniently tuned a previous well-validated algorithm and we have assessed its performance. To this end, we have used real traces from public repositories, from a Spanish 3G operator, and synthetic traces. Our results show that a single process can detect Skype traffic at 1 Gbps rates reading replayed real traces directly from a NIC. Even more, 3.7 Gbps are achieved reading from traces previously allocated in memory using a single process and 45 Gbps using 16 concurrent processes. This fact paves the way for 10 Gbps processing in commodity hardware.