+-------------------------------------------------------------+ | HSS (Database) | +------------------------------+------------------------------+ | | S6a | +------------------------------+------------------------------+ | MME (Control Plane) | +--------------+------------------------------+---------------+ | | | S1-MME | S11 | | +--------------+---------------+ +---------------+ | eNodeB | | S-GW | +--------------+---------------+ +-------+-------+ | | | S1-U | S5/S8 +--------------------------------------+ | +-------+-------+ | P-GW | +-------+-------+ | SGi +-------+-------+ | PDN / IP | +---------------+
The Evolved Packet Core (EPC) is the core network framework introduced by the 3rd Generation Partnership Project (3GPP) in Release 8. It represents a paradigm shift from legacy 2G/3G networks by introducing a . generates charging keys
Handles lawful interception and charging functionality. E. PCRF (Policy and Charging Rules Function) creates the Default Bearer
Tracks the user’s location, handles paging, manages user authentication, and performs idle-state mobility. It handles the NAS (Non-Access Stratum) signaling between the UE (User Equipment) and the network. B. HSS (Home Subscriber Server) Role: The central database. manages user authentication
The P-GW assigns an IP address, generates charging keys, creates the Default Bearer, and returns a Create Session Response via the S-GW to the MME.
Connects the S-GW to the P-GW (S5 within the same network; S8 during roaming).
The EPC separates the control plane (signaling) from the user plane (data traffic) to allow independent scaling. It consists of four primary network entities: