| Interface | Description |
| Cx | I/S-CSCF<->HSS |
| Gx | PCEF<->PCRF |
| Gy | PCEF<->OCS |
| Ro | AS <->OCS |
| Rx | AF<->PCRF |
| Sh | AS<-> HSS |
| Sy | OCS<->PCRF |
| S6a | MME<->HSS |
| S6d | SGSN<->HSS |
| S9 | vPRCF<->hPCRF |
| Cx | I/S-CSCF<->HSS |
| Gx | PCEF<->PCRF |
| Gy | PCEF<->OCS |
| Ro | AS <->OCS |
| Rx | AF<->PCRF |
| Sh | AS<-> HSS |
| S13 | MME-EIR |
| Gxa | Trusted Non-3GPP IP access-PCRF |
| Gxc | Serving Gateway-PCRF |
| SWd | 3GPP AAA Server-3GPP AAA Proxy |
| SWx | 3GPP AAA Server-HSS |
| SWm | ePDG-3GPP AAA Server/Proxy |
| SWa | Untrusted Non-3GPP IP access-3GPP AAA Server/Proxy |
| STa | Trusted Non-3GPP IP access-3GPP AAA Server/Proxy |
| S6b | PGW-3GPP AAA Server |