- P-CSCF: acts as an Access SBC with full transcoding support and other features. Interfacts with the PCRF to provide quality of service management
- I-CSCF: provides full Cx/Dx interface support and selects S-CSCF based on user capabilities and load
- S-CSCF: provides flexible application execution using a standards-based ISC interface and allows optional charging integration with standard Ro/Rf interfaces
- IP-SM-GW: provides SMS services for VoLTE and legacy devices and allows interworking towards other networks based on SMPP
- MRF: provides network announcements and conferencing
- LI: Provides X1 to X3 interfaces for lawful interception.
