Impact of dynamic priority scheme on IP Multimedia Subsystem

IP Multimedia Subsystem (IMS) has been standardized by 3GPP/3GPP2 to provide essential services to users of the 4G and beyond. Its capabilities to scale and integrate with Next Generation Network (NGN) has given IMS widespread applicability in the Next Generation Networks (NGN). IMS relies heavily on SIP (Session Initiation Protocol) to insure initialization, negotiation and termination of services. This work proposes a dynamic priority scheme for SIP messages within the IMS system, thereby reducing the session setup delay and improving the user experience. IMS services execution requires a SIP message to revisit IMS main servers multiple times. Each service varies in the numbers of re-visitations to these servers. The work propose that when a message first arrives at a server it will be assigned with zero priority (the least priority), and the message´s priority will increase by one every time the message visits a server. The higher the message priority the faster the processing will be. The idea of this approach is to process the ongoing signaling of a service among servers faster, consequently more requests can be processed in shorter time Additional SIP header is required to implement the scheme. QoS is a key measurement for the user experience. It is essential to provide services with guaranteed QoS. The scheme proposed here facilitates service providers to deliver guaranteed QoS and, possibly develop successful business models for revenue generation.