Architecture Explorer

Inside the Network

How each generation is wired — from the handset to the internet.

Radio / AccessControl PlaneUser PlaneManagement

User Equipment

Radio / Access

LTE handset

eNB

eNodeB

Radio / Access

LTE base station with integrated RNC functions

MME

Mobility Management Entity

Control Plane

Manages authentication, handoff, and paging

SGW

Serving Gateway

User Plane

Routes user data plane; handles handoffs

PGW

PDN Gateway

User Plane

IP address allocation; internet gateway

HSS

Home Subscriber Server

Management

Subscriber database (evolved HLR)

PGW → Internet

4G EPC (Evolved Packet Core)

Flat, all-IP architecture. The EPC separates the control plane (MME) from the user plane (SGW/PGW). No circuit-switched domain — voice runs as VoLTE over the data plane.