Manual

Cisco Packet Data Serving Node (PDSN) Release 2.0
Resource Management
17
12.3(11)T
When threshold for the quota is reached, the PDSN sends an Access Request to HAAA to retrieve more
quota for the flow. In case the values of threshold for the quota and the quota allocated are same, then
on quota expiry (when Quota = Threshold), the PDSN will treat this as flow as closed, and send an
Access Request with Update-reason as “Quota reached”.
When the quota expires for the flow, the PDSN sends an on-line Access Request to the HAAA to indicate
that the prepaid flow is released. During this time the PDSN marks the flow as deleted, and stops
switching any packets for the flow. On receipt of the Access Accept from the AAA server for this Access
Request, the PDSN deletes the prepaid flow for the user and sends an Accounting Stop.
If resource revocation mechanism is enabled at the PDSN, then the PDSN will send a resource revocation
to the HA to clear binding at the HA, and the PDSN will clear the visitor info for the flow.
Upon receiving a RADIUS Disconnect Request (POD) or Mobile IP revocation messages, the PDSN will
send an on-line RADIUS Access-Request message containing the used quota and the Update-Reason
Sub-Type set to “Remote forced disconnect”. The PDSN will delete the flow and send resource
revocation message to the HA, and will send the existing RADIUS Accounting-Stop.
Volume-based Prepaid Data Service Flow
The metric for accounting volume based Prepaid service is total bytes flowing through the user flow in
upstream and downstream direction.
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, the use has to be
authenticated with AAA instead of local authentication. In case of Mobile IP users, FA-CHAP
authentication is required.
The PDSN includes its own PPAC VSA to inform the HAAA/Billing Server that it supports Prepaid
based on Volume (value = 1 or 3). If resource revocation is enabled on the PDSN, then it will send a
SessionTerminationCapability (STC) attribute indicating that it can support resource revocation for
Mobile IP sessions.
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, HAAA interfaces with the
Billing Server, and provides the Billing Server with the prepaid info for the user as received in the Access
Request message.
Step 2 After the Billing Server receives the user’s prepaid information, it checks the capabilities of PDSN (sent
in the PPAC VSA). The Billing Server also checks that the user has a valid balance and account status.
The Billing Server then indicates to the PDSN that it supports prepaid packet data service based on
volume. 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 the
user for the current quota. The Billing Server interfaces with HAAA and provides this information 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 VolumeQuota parameter
– Quota ID for the quota allocated
– A threshold value for the quota allocated in VolumeThreshold parameter
• A PPAC VSA indicating prepaid service is based on Volume.