Cisco Cisco IOS Software Release 12.4(2)XB6

The A10 interface is for user data and the A11 interface is for control messages. This interface is also 
known as the RAN-to-PDSN (R-P) interface. 

 illustrates the communication between the RAN 

and the Cisco PDSN. 

The IP networking between the PDSN and external data networks is through the PDSN-to-intranet/Internet 
(P

i

) interface. For the Cisco PDSN Release 2.0 and above, you can use either an FE or GE interface as 

the P

i

 interface.

For “back office” connectivity, such as connections to a AAA server, or to a RADIUS server, the 
interface is media independent. Any of the interfaces supported on the Cisco 7206 can be used to connect 
to these types of services; however, Cisco recommends that you use either an FE or GE interface.

When a mobile station makes a data service call, it establishes a Point-to-Point Protocol (PPP) link with 
the Cisco PDSN. The Cisco PDSN authenticates the mobile station by communicating with the AAA 
server. The AAA server verifies that the user is a valid subscriber, determines available services, and 
tracks usage for billing.

The method used to assign an IP address and the nature of the connection depends on service type and network 
configuration. Simple IP operation and Mobile IP operation are referred to as service types. The service 
type available to a user is determined by the mobile station, and by the type of service that the service 
provider offers. In the context of PDSN, a mobile station is the end user in both Simple IP and Mobile 
IP operation.

Once the mobile station is authenticated, it requests an IP address. Simple IP stations communicate the 
request using the Internet Protocol Control Protocol (IPCP). Mobile IP stations communicate the request 
using Mobile IP registrations. 

The following sections describe the IP addressing and communication levels for each respective topic:

RAN

BTS

BSC

PCF

R-P Interface

PDSN

Mobile station

PPP

GRE

PPP

IP

42688

IP