Research And Design On Evolved Packet Core User Plane Using Software-Defined Network

Traditional network bind control logic and data forwarding onto network devices, which leads to a larger network scale, making the management of control plane more and more complex. The network architecture will become clearer when we decouple the control part from traditional network devices and place them to a higher palce in the network. Without control and decision making capability, network equipment will become a pure forwarding element. At the same time, the network control function decoupled from the network itself will make a central controller, we can define rules to control the flows in the network. Different network users have different demands, one can develop software above the controller to satisfy different needs. This "software defining--centrolized control--pure forwarding" concept is called Software defined network.Comparied to2G/2.5G GPRS network architecture, the architecture of EPC(Evolved Packet Core) has a trend to evolve to a flatter one, the control and user plane trend to decouple. The user plane includes S-GW(Serving Gate Way) and P-GW(Public Data Network GateWay). S-GW distract function which relate to mobile management from SGSN(Serving GPRS Support Node) in order to bear user data. P-GW is like GGSN(Gateway GPRS Support Node) in GPRS, acting as a gateway to Core Network and outer data network, whose function is sort of like routers in traditional Internet.Openflow is an important protocol in Software-defined network, it defines forwarding packets’ format, data structure and options used for manipulate flows. There are switchs supporting Openflow1.0and1.3in the market.This essay starts with SAE(System Architecture Evolution) architecture, and the EPC part uses SDN’s centrolized control and distributed fowrding concept, planning to use SDN’s key technology and protocol, trying to combine SDN with EPC’s user plane(including S-GW and P-GW), then come up with a new architecture which is a combination of Software-defined network and EPC.