Observing the Impact of QoS Negotiation on the Signaling Load of the IMS

Abstract

Defined by the 3GPP, the IP Multimedia Subsystem (IMS) is becoming the de facto overlay architecture for enabling service delivery in converged environments. In such scenarios, the QoS requirements of the delivered services vary from user to user, and from service to service. To cope with this necessity, the IMS allows subscribers to personalize the QoS settings of the session that they want to establish. In order to know the impact that the requested QoS parameters have on the available network resources, it is of paramount importance to know how the signaling load in the core network is influenced by them. With this goal in mind, this paper shows how the IMS SIP signaling load is affected when users change their QoS parameters when negotiating a session. The observations were done on a testbed based on the Open IMS Core implementation of the Fraunhofer FOKUS Institute at Berlin and on the IMS Client developed at the University of Cape Town.