Evolved Packet Core (EPC)
This move to a simpler flat architecture is a key difference between LTE and earlier 3G networks, which comprised circuit-switched and packet elements for voice and data respectively. The flat architecture should cut the raw cost of delivering data across the network once capex costs have been recouped but requires the core network to be much smarter about how it prioritizes voice, video, and data traffic, since everything is sent via one big pipe.
The EPC proper is made up of the Mobility Management Entity (MME), which manages mobile device connection to LTE and other mobile networks, the Serving Gateway (SGW), the element that routes the data packet; and the PDN Gateway (PGW), which connects the mobile user to external packet networks. Operators and vendors are now examining using EPC as a common core for 2G, 3G, and LTE. (See 3G Fuels Mobile Packet Core.)
SGSN vendors include Alcatel-Lucent (NYSE: ALU), Cisco Systems Inc. (Nasdaq: CSCO), Ericsson AB (Nasdaq: ERIC), Huawei Technologies Co. Ltd. , Nokia Networks , and ZTE Corp. (Shenzhen: 000063; Hong Kong: 0763).