Call and messaging performance comparison between IMS and SIP networks

The IP Multimedia Subsystem (IMS) has been considered to be exclusive to big players of the telecommunication world. Session Initiation Protocol (SIP) has been standardized by IETF and solutions based on it have been in the market at least for a decade. It is also an essential part of the IMS, as it is the control protocol of IMS. Recent development of the Linux platform and the Open source IMS system has lead to a situation where the IMS is also an affordable solution for smaller telecommunication companies. The obvious question has been whether the level of performance with Open source IMS is really suitable for business usage. ETSI-TISPAN has unified IMS performance measurements by defining a common framework which to follow in measurements. The paper presents comparisons between IMS and SIP based networks in call and messaging performance. the Open IMS solution by the Fraunhover Focus Institute is compared with the OpenSIPS, an open source SIP server. The number of users in our measurements 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.