The EPC is the latest evolution of the 3GPP core network architecture. Evolved Packet Core (EPC) is a framework for providing converged voice and data on a 4G Long-Term Evolution (LTE) network.
EPC was first introduced by 3GPP in Release 8 of the standard. It was decided to have a "flat architecture". The idea is to handle the payload (the data traffic) efficiently from performance and costs perspective. Few network nodes are involved in the handling of the traffic and protocol conversion is avoided.
It was also decided to separate the user data (also known as the user plane) and the signalling (also know as the control plane) to make the scaling independent. Thanks to this functional split, the operators can dimension and adapt their network easily.