Registration performance comparison between IP Multimedia Subsystem and Session Initiation Protocol networks

The IP Multimedia Subsystem (IMS) is an IP based service control framework architecture. It uses Session Initiation Protocol (SIP) to control its multimedia sessions. The IMS core can be considered as a collection of different functions that are linked with standard interfaces, forming an IMS core network. The IMS has layers for transport, the core itself, and for services and applications. The complexity of the IMS core is greater than within pure SIP based networks. To help to make comparisons between different IMS networks, the ETSI-TISPAN has unified the IMS performance measurements by defining a common framework which to follow. In this paper, the Open IMS solution by the Fraunhover Focus Institute is compared with the OpenSIPS, an open source SIP server used for user's registrations to network. The number of users was chosen to be 100 000, a large enough number to be considered as a suitable number of users for small or moderate business usage needs. Our study shows that both of the systems are able to handle this many users and, in the case of OpenSIPS, with a clear margin. It was also discovered that both systems are reliable and are suitable for small and moderate business usage and further performance study trials.