Network initiated inter UE session transfer control in IMS

The Next Generation Network will encompass diverse access technologies, devices and services. In order to provide a user the best service experience in that circumstance, the NGN will cover not only terminal mobility, which is the main concern in current mobile network domain, but also personal mobility and service mobility. The IMS architecture, which is considered as session control layer in NGN, and SIP is the basic protocols for controlling sessions in IMS. Therefore, Session mobility management in NGN is tightly coupled with IMS and SIP. There could be a few ways how to control session mobility in IMS. Basically, Session mobility can be controlled in UE based or network based. In UE based approach, a UE initiates the session transfer while network initiates a session transfer in network based approach. This paper especially focuses on the network initiated session transfer. This paper describes how the network initiated session transfer using SIP is implemented in IMS in detail.