LTE - EPC Overview (Study Note)

LTE - EPC Overview (Study Note)












IASA includes:
- 3GPP Anchor
- SAE Anchor

EPC includes:
- MME
- P-GW:SAE Anchor
- S-GW:3GPP Anchor+UPE

EPC Interface: (Internal)
- S10: MME -- MME
- S11: MME -- S-GW
- S5: S-GW -- P-GW
- S8: (V-P) S-GW – (H-P) P-GW (for Roaming)

EPC Interface: (External)
- S1-C: MME -- eNB
- S1-U: S-GW -- eNB
- S2a: P-GW -- Non-3GPP Trusted IP-Access
- S2b: P-GW -- ePDG of 3GPP WLAN
- S3: MME -- SGSN
- S4: S-GW -- SGSN
- S6a: MMW -- HSS
- S6b: P-GW -- HSS
- S6c: P-GW -- HSS (as an AAA)
- S7: P-GW -- (V-/H-) PCRF
- S13: MME -- EIRS
- S101: MME -- CDMA eAN PCF
- S103: S-GW -- CDMA PDSN
- SGi: P-GW -- P-CSCF
- SGs: MME -- MSC
- S6d: SGSN -- HSS
- S12: eNB -- S-GW -- SGSN (Direct Tunnel)

- S13’: SGSN -- EIR
- S14: UE -- ANDSF (OMA DM)

Mobility management entity (MME): Manages and stores the UE control plane context, generates temporary Id, UE authentication, authorisation of TA/PLMN, mobility management
- The MME manages and stores UE context (for idle-state: UE/user identities, UE mobility state, user security parameters). ŸIt generates temporary identities and allocates them to UEs.
- UE authentication, authorisation of TA/PLMN, mobility management: It checks whether the UE may camp on the TA or on the PLMN. It also authenticates the user.

User plane entity (UPE): Manages and stores UE context, DL UP termination in LTE_IDLE, ciphering, mobility anchor, packet routing and forwarding, initiation of paging
- The UPE terminates, for idle-state UEs, the downlink data path and initiates paging when downlink data arrives for the UE.
- It manages and stores UE contexts, such as parameters of the IP bearer service, or network internal routing information.
- It performs replication of the user traffic in case of interception.

3GPP anchor: Mobility anchor between 2G/3G and LTE ŸThis is a functional entity that anchors the user plane for mobility between the 2G/3G access system and the LTE access system.

SAE anchor: Mobility anchor between 3GPP and non 3GPP (I-WLAN, etc)
- This is a functional entity that anchors the user plane for mobility between 3GPP access systems and non-3GPP access systems.

Further Study: https://docs.google.com/fileview?id=F.faf445b2-5c26-458f-921e-9216357a0b8e