dc.description.abstract | With the high crime rate society, lawful interception is used to get the communication of the offenders. Interception of the traditional telephone is used to solve the criminal cases before. But following to the popularization of the Internet, people uses Voice over Internet Protocol (VoIP) and video conference to communicate with each other generally. Thus, the research of the interception with the network will be an important subject. The common protocols of VoIP include H.323 and SIP. H.323 has the complete structure. Interception of H.323 is just established the wiretap mechanism on the path of the communication. However, SIP rules the establishment of the connection only, the path of the transmission is not defined. Therefore, It is hard to intercept the media streams. Especially, when SIP is operated with mobile IP, It is hard to be aware the path of the communication and get the mobile information.
In this paper, three SIP wiretap strategies with mobile IP are proposed, including Centralized Wiretap-Agent-based Interception Strategy (CWAIS), Distributed Wiretap-Agent- based Interception Strategy (DWAIS) and Home-Agent- based Interception Strategy (HAIS). Each advantage and disadvantage of these strategies will be analyzed and compared. In this paper, HAIS is chosen to be implemented. That is because it can be operated with current network. And the SIP clients can not be aware that they are intercepted. Finally, the experiments are designed for this system with several parameters. The feasibility can be verified and the experimental results are analyzed. | en_US |