Open Source IMS implementations

The diploma thesis deals with open source implementations of IMS technology. The theoretical part describes the functioning of IMS and its architecture, including the protocols used, the process of registration and connection establishment, as well as potential security threats to IMS systems. Two open source IMS projects were selected, Open IMS Core and Project Clearwater, on which the work is focused. In its next part, the diploma thesis deals with the description of selected open source IMS projects, this part also includes a description of the implemented security of both projects and a detailed procedure of system installation with any necessary configuration. In its practical part, the diploma thesis focused on performance testing of selected projects using the Abacus 5000 hardware tester. First, initialization tests were performed, which verified the possibility of communication between the tester and the tested projects. Subsequently, it was possible to perform performance testing of selected projects. In performance testing, emphasis is placed on system stability, performance in the area of call set-up speed and response time of SIP messages and speed of user registration in the network, at different load levels. The systems have been tested for both call set-up and user registration. Part of the testing is also the implementation of the flood DoS inviteflood attack and the system's response to the increasing intensity of the attack. The last chapter is devoted to the comparison of selected IMS projects, where the test results are clearly presented. This chapter is partly based on publicly available information, such as the technical documentation of individual projects and possibly publicly available mailing lists. Part of the diploma thesis is also a laboratory task in which the student tries to work with Open IMS Core. The laboratory task focuses on the process of creating a user and his registration in the IMS network, establishing a call between individual users and internal routing in IMS networks. The task focuses mainly on signaling processes within the implemented tasks