Manual

Cisco Packet Data Serving Node (PDSN) Release 2.0
Resource Management
19
12.3(11)T
Step 8 The Billing Server does not allocate a new quota when the user indicates “Quota reached” for the prepaid
flow. The Billing Server terminates the prepaid flow and indicates the same to the HAAA. The HAAA
sends an Access-Accept message to the PDSN acknowledging the termination of the Prepaid packet data
session by encapsulating Update Reason Sub-type as “Quota is reached” inside PPAQ VSA.
After the PDSN receives the Access Accept message, it deletes the user flow for the Prepaid session. As
part of the usual off-line accounting procedures, the PDSN sends an off-line RADIUS Accounting-Stop
message upon successful release of the appropriate resources (normal operation).
Duration-based Prepaid Data Service Flow
The metric for accounting duration-based Prepaid service is session duration in seconds.
Step 1
The Prepaid capable PDSN determines that Simple IP or Mobile IP setup requires a RADIUS
Access-Request message to be sent to the Home RADIUS Server. For SIP sessions, user authentication
has to be performed with AAA rather than local authentication. In the case of Mobile IP users, FA-CHAP
is required for authentication.
The PDSN includes its own PPAC VSA to inform the HAAA/Billing Server that it supports Prepaid
based on Duration (value = 2 or 3). If resource revocation is enabled on the PDSN, the PDSN will send
a SessionTerminationCapability (STC) attribute indicating that it can support resource revocation for
Mobile IP sessions. The Event_Time attribute (G4, value = 55) will be included in the RADIUS
Access-Request message.
The Home RADIUS server performs the regular Authentication and Authorization of the Access Request
sent by the user. If the user profile indicates the user is a Prepaid subscriber, the HAAA interfaces with
the Billing Server and provides the Billing Server with the prepaid related info for the user as received
in the Access Request message.
Step 2 After the Billing Server receives the user’s prepaid info, it checks the capabilities of the PDSN (sent in
the PPAC VSA). The Billing Server also checks that the user has a valid balance and account status. The
Billing Server informs the PDSN that it supports prepaid packet data service that is based on Duration.
It also assigns the initial quota for the user, which is typically a fraction of total available quota for the
user. The quota allocated for the user is identified by a quota id assigned by Billing Server for that user
for the current quota. The Billing Server interfaces with the HAAA and provides this info to the HAAA.
The HAAA encapsulates the prepaid information received for the user in a RADIUS Access-Accept
message and sends it to the PDSN. The RADIUS message includes:
A PPAQ VSA that contains the following parameters:
• Initialized quota for the user flow specified in DurationQuota parameter
• Quota ID for the quota allocated
• A threshold value for the quota allocated in DurationThreshold parameter
A PPAC VSA that indicates prepaid service is based on Volume.
For duration based Prepaid packet data service, the Event_Time attribute is used for
DurationQuota/DurationThreshold allocation by the Billing Server.
After the PDSN receives the Access-Accept message from AAA, it parses the RADIUS packet and
retrieves the attributes inside it. The PDSN stores information in the packet regarding the quota allocated
for the flow, and threshold corresponding to the allocated flow. It also stores the Quota-ID allocated
corresponding to the quota.