A Novel P2P Approach to S-CSCF Assignment in IMS

In IP Multimedia Subsystem (IMS), Interrogating Call Session Control Function (I-CSCF) assigns the most suitable Serving-CSCF (S-CSCF) to the user performing IMS registration, which is defined by the Third Generation Partnership Project (3GPP) as S-CSCF assignment. Current approaches to implement S-CSCF assignment, however, incur the low utilization of S-CSCF resources. In this paper, we design a hybrid Peer-to-Peer (P2P) based S-CSCF overlay network called Hyson. Based on Hyson, we propose a novel approach to implement S-CSCF assignment called HSA, which can enhance the utilization of S-CSCF resources. HSA is accomplished by collaborative work of S-CSCFs. Simulation results show that HSA enables not only IMS network to have a much greater user capacity but also S-CSCFs to produce much smaller processing delay than current approaches.