Analysis of Traffic Identification Methods in Encrypted Voice Transmission

The use of Voice over IP technology is rapidly growing and in the near future it can completely replace traditional PSTN network. The main strong reasons for the use of this technology is a huge reduction of costs, and a significant increase in terms of functionality switched networks. In the past, applications that provide VoIP services were dedicated exclusively to computer users. Today, IP telephony can be used virtually anywhere where one has the access to the Internet and IP networks. The nature of the medium used which is a packet network has some disadvantages, and correcting those is of an interest for telecom operators, telecoms regulators and companies who want to prioritize or block the VoIP traffic for a variety of reasons. Four basic methods of detection are used for this purpose: Port-based filters, keywords, ASCII string patterns, signaling patterns and statistical analysis packages.