Quality of protection analysis and performance modeling in IP multimedia subsystem

IP Multimedia Subsystem (IMS) is widely considered as the main solution for the next generation multimedia rich communication. In order to provide multi-level security service in IMS to mobile users for multimedia applications, it is insufficient to take the security benefits into consideration, but adequately analyzing the impact of security policies in IMS on the performance cost quantitatively is also necessary and significant. In this paper, we first propose a novel study of IMS performance by a QPN model to much more precisely describe SIP signaling in IMS, and made performance evaluation. Then we defined totally seven levels of IMS security policies according to IMS specifications in 3GPP and proposed QoP partition model which quantitatively reflects strength of protection of SIP signaling and users' security needs. Further more, we did our original contributions to use the QPN model to evaluate the impacts of security mechanism on system performance cost quantitatively. With the multi-view security partition introduced, different security policies could be adjusted according to the application and users' security requirements, so that multi-level security service can be provided to diverse users and applications for a better tradeoff between security requirements and system performance in IMS.