implemented an IMS testbed comprising P-CSCF, I-CSCF
, S-CSCF, HSS and DNS on top of an OpenStack cloud and proposed an efficient IMS-as-a-Service architecture .
Simulates P-CSCF, I-CSCF
, S-CSCF, PCRF, HSS, BGCF, MGCF elements in LTE IMS network supporting Cx/Dx, Rx, Gx, Gm, Mw, SGi, Mi, and Mj interfaces
Here are the main functions of I-CSCF : a) the S-SCSF assignation for users which are performing SIP registration procedures, b) interrogates the HSS node during UE initiated session setup to get the address of the S-CSCF and forwards the SIP request/respond messages to it.
2) P-CSCF examines request and sends to appropriate I-CSCF with all needed information.
Other nodes, like I-CSCF and HSS are not so loaded in scenarios with visiting subscribers (refer Fig.
248 Mp, Mn HTTP Ut Not specified Ml, Mx, Ix, Iq Protocol Involved entities SIP UE, P-CSCF, I-CSCF
, S-CSCF, AS, IBCF, MGCF, BGCF, MRFC Dismeter I-CSCF
, S-CSCF, HSS, SLF, AS, SIP AS, OSA SCS, OSA SCF, IM-SSF, PCRF, MRCF, OCS, BCF, MGCF, IBCF, CDF MAP (Mobile IM-SSF, HSS Application Part) H.
P-CSCF is the first contact point in the signaling plane between the IMS terminal and the IMS network, and the I-CSCF is a SIP proxy located at the edge of an administrative domain.
The address of the I-CSCF is listed in the DNS (Domain Name System) records of the domain.