EPC (Evolved Packet Core)
Updated
The EPC is the core network of 4G LTE. Its main elements are the MME, which handles signalling and mobility, the serving gateway (SGW) and the packet gateway (PGW), which carry user data, and the HSS, which holds subscriber data. Its architecture is defined in 3GPP TS 23.401.
In practice
LTE-M and NB-IoT also run on the EPC. An operator that runs its own EPC decides where device traffic leaves the mobile network, which is the starting point of any private delivery.