interfaces

C interface is between the MSC and HLR.

Gn interface is between the SGSN and GGSN.

Gr interface is between the SGSN and HLR.

Gx interface is between the PCEF and PCRF.

Gy interface is between the PCEF and OCS.

S1 interface is between the eNB (eNodeB) and the MME (Mobility Management Entity).

S10 interface is between the MME and MME.

S11 interface is between the MME and SGW.

S12 interface is between the RNC and SGW.

S2b interface is between the PGW and ePDG.

S3 interface is between the MME and SGSN.

S4 interface is between the SGSN and SGW.

S5/8 interface is between the SGW and PGW.

S6a interface is between the MME (Mobility Management Entity) and HSS (Home Subscriber Server).

S9 interface is between the Visiting PCRF and Home PCRF.