4G EPC — Evolved Packet Core
The actual wiring of the network — curated from 3GPP TS 23.401, baseline Rel-8.
Network Topology — shows the actual wiring of the network functions (interfaces, protocols, data flow), verified against the specification. For conceptual relationships between terms, switch to the Knowledge Map.
Control PlaneUser PlaneShared Data LayerNetwork functions are grouped into functional groups. Click a node for its glossary definition.
Interfaces and reference points
| Interface | Between | Type | Protocol | Source |
|---|---|---|---|---|
| LTE-Uu | UE ↔ E-UTRAN (eNB) | logical-association | — | TS 23.401 · Figure 4.2.1-1 (Non-roaming architecture) |
| S1-MME | E-UTRAN (eNB) ↔ MME | logical-association | s1ap | TS 23.401 · Figure 4.2.1-1 (Non-roaming architecture) |
| S1-U | E-UTRAN (eNB) ↔ S-GW | logical-association | gtp-u | TS 23.401 · Figure 4.2.1-1 (Non-roaming architecture) |
| S11 | MME ↔ S-GW | logical-association | gtp-c | TS 23.401 · Figure 4.2.1-1 (Non-roaming architecture) |
| S6a | MME ↔ HSS | logical-association | diameter | TS 23.401 · Figure 4.2.1-1 (Non-roaming architecture) |
| S5/S8 | S-GW ↔ P-GW | logical-association | gtp | TS 23.401 · Figure 4.2.1-1 (Non-roaming architecture) |
| SGi | P-GW ↔ PDN | logical-association | — | TS 23.401 · Figure 4.2.1-1 (Non-roaming architecture) |
| Gx | PCRF ↔ P-GW | logical-association | diameter | TS 23.401 · Figure 4.2.1-1 (Non-roaming architecture) |