The PCF, Packet Control Function, provides RLP, (Radio Link Protocol) termination from the Data Capable Mobiles. In turn, the PCF sets up a R-P tunnel, (Radio-Packet) to the PDSN(Packet Data Serving Node) for A10/A11 traffic. Typically, the PCFs would have a PDSN file to which the mobile can hash to. The PDSNs authenticate the mobile via a AAA server that has profiles set for each mobile(includes the MIN/ESN of the mobile). The PDSN needs to be provisioned with the IP address of the PCFs..
The MSC(SM/PSU) handles all RLP traffic from the cell from which the call originates in the form of F.Relay SVCs to the PCFs(Sun Servers with T1 interface cards).
This was an overview & hope it helps.