OVERALL EPS OVERVIEW: WHAT IS EPS?

EPS Stands for Evolved Packet System (EPS) . It is made up of EPC(Core Network ) and E-UTRAN (RAN). As shown in the figure below.

EPC High level Information

The EPC provides access to external data networks. ( e.g., internet , corporate networks etc.) and operator services.

It also performs services such as

• security related (authentication , key agreement)
• Subscriber information
• Charging
• Inter-access mobility (GSM / WCDMA / LTE / CDMA ).
• Core network also keeps track of the mobility of inactive terminals i.e., Idle mode users

RAN High Level Information

RAN side provides all radio related functions for active terminals meaning the terminals sending data.