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On Metrics to Distinguish Skype Flows from HTTP Traffic

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Abstract

Skype is a Voice over IP (VoIP) Internet application that is gaining huge popularity in recent years. A key point to Skype popularity is its capability to dynamically adapt itself to operate behind firewalls or network proxies. A common way adopted by Skype to delude these network devices is to use port 80, normally expected to comprise HTTP traffic. In this paper, we propose metrics and investigate statistical tests intended to clearly distinguish Skype flows from HTTP traffic. We validate our study using real-world experimental datasets gathered at a commercial Internet Service Provider (ISP). Our experimental results suggest that the proposed methodology may be seen as a promising building block towards a system to detect general protocol anomalies in HTTP traffic.

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Acknowledgments

The authors would like to thank Marcos Gomes Pinto Ferreira, Marcos Vinícius do Couto, and all other staff members of the commercial ISP that kindly helped us to get the Web experimental datasets used in this work. This work was supported by the Brazilian Army, CNPq, and FAPERJ.

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Authors and Affiliations

  1. Military Institute of Engineering (IME), Praça General Tibúrcio, 80, 22290-270, Rio de Janeiro, RJ, Brazil

    Emanuel Pacheco Freire & Ronaldo Moreira Salles

  2. National Laboratory for Scientific Computing (LNCC), Av. Getúlio Vargas, 333, 25651-075, Petrópolis, RJ, Brazil

    Artur Ziviani

Authors
  1. Emanuel Pacheco Freire
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  2. Artur Ziviani
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  3. Ronaldo Moreira Salles
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Corresponding author

Correspondence to Artur Ziviani.

Additional information

This paper is an extended version of [1].

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Freire, E.P., Ziviani, A. & Salles, R.M. On Metrics to Distinguish Skype Flows from HTTP Traffic. J Netw Syst Manage 17, 53–72 (2009). https://doi.org/10.1007/s10922-009-9120-x

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