CS-CN - Circuit Switched Core Network -
These networks are involved in voice transfers, authentication, mobility management, billing ...
PS - CN - Packet Switched core Network -
These networks are involved in Internet connectivity, packet transfers, multimedia connections, mobility management, security, usage management ....
All IP core networks -
In all IP networks there is no separation of CS-CN and PS-CN. Both voice and data are handled as packets.
All IP is a unified network core for wireless operators to handle both voice and data.
If the approach of unified core of all IP is adopted across majority of carriers globally, then mobility will become seamless.
Currently 3G networks are primarily divided into circuit switched and packet switched networks. There are various levels of complexities involved at each core network. Lets discuss primary roles of Circuit switched CN, Packet Switched - CN and all-IP in wireless data communications.