Hi @uts09 , I think there are several misunderstandings. 1) scscf.xml is read by the cdp module, not by the ims_isc module 1a) The SAR message to the HSS is not triggered by the ims_isc module, but by the ims_registrar_scscf module, afaik 2) The HSS does not process SIP requests, but it processes DIAMETER 3) Are you sure, you have a Scenario, where you send an Initial INVITE with a PSI in the Request Line? 4) Have you configured the PSI at the HSS?