EPC

Evolved Packet Core

Core Network

Introduced in Rel-8

All-IP core network architecture for LTE providing mobility, session, and policy management.

Description

The Evolved Packet Core (EPC) is the core network for LTE, providing all-IP connectivity with seamless mobility. It consists of MME (control plane), S-GW/P-GW (user plane), HSS (subscriber data), and PCRF (policy).

EPC eliminates circuit-switched domain, treating all services as packet data. It supports multiple access technologies and provides seamless handover between LTE and legacy networks.

Purpose & Motivation

EPC was designed to:

- Provide all-IP flat architecture for lower latency - Separate control and user planes for scalability - Support diverse access technologies (LTE, Wi-Fi, 3G) - Enable policy-based QoS and charging

Key Features

  • All-IP architecture
  • Flat network design
  • Control/User plane separation
  • Policy and charging control
  • Multiple access support
  • Seamless mobility

Evolution Across Releases

Rel-8Initial

Initial EPC architecture

CUPS (Control/User Plane Separation)

Interworking with 5GC for NSA deployment

Defining Specifications

SpecificationTitle
GPRS enhancements for E-UTRAN access
Architecture Enhancements for non-3GPP accesses
Policy and Charging Control Architecture