Manual

Cisco Packet Data Serving Node (PDSN) Release 2.0
Resource Management
16
12.3(11)T
When the Billing Server successfully authorizes the user as a valid prepaid user, it notifies the HAAA
that it supports prepaid service based on volume, or duration, or both, depending on the configuration at
the Billing Server and capabilities as indicated by the PDSN. The HAAA encodes the information in a
PPAC VSA to the PDSN, and indicates that volume-based or duration-based prepaid (or both) service is
supported by the Billing Server.
HAAA sends the authorization response to the Prepaid capable PDSN using RADIUS
Access-Accept/Reject messages. The authorization response includes a PPAQ VSA in the same
RADIUS Access-Accept message stating an initial quota, quota-id and a threshold value of the quota for
the prepaid flow corresponding to the user.
When the PDSN sends on-line Access Request messages to HAAA for prepaid related functionality, it
does not set the User-Password (= 2) field in the message, and normal RADIUS message authentication
is set and performed with Message Authenticator. Currently, the User-Password is set in online Access
Requests to the default value of “cisco”.
If the PDSN does not receive the PPAC VSA from the HAAA in the initial RADIUS Access-Accept
message, or the message is included but indicates that “Prepaid Accounting not used”, the PDSN will
release the user’s prepaid flow if the RADIUS Access-Accept message includes a PPAQ VSA. The
PDSN will send an Access Request to HAAA to return the quota allocated with Update-Reason VSA
that indicates Client Service termination.
If the PDSN is capable of supporting prepaid service based on either volume or duration, then the PDSN
will enable prepaid service for the flow based on the Billing server-indicated service that applies to the
session in PPAC. If the Billing server also indicates that the PDSN can allocate either volume or
duration, then the PDSN will enable prepaid service based on the type of quota (volume or duration)
present in PPAQ from HAAA. If both types of quota are present in PPAQ, then prepaid flow is not opened
on the PDSN.
If the PDSN is capable of supporting prepaid service based on volume, and Billing Server indicates that
it will support prepaid service based on duration, then the PDSN will close the prepaid flow. The PDSN
will send an Access Request message with Update-Reason VSA indicating “Client Service termination”.
The same logic applies to the PDSN if it supports prepaid based on duration, and Billing Server returns
prepaid service based on volume.
If the PDSN receives an Access-Accept message containing the PPAC VSA indicating prepaid service
supported, but the initial quota is not included in the message, the PDSN will close the flow. Since no
quota was received in the Access Accept, the PDSN will not send further RADIUS Access Request
message to HAAA.
To ignore Billing Server interaction of HAAA for Access Requests sent by the PDSN during mobile IP
re-registration for FA-CHAP, the PDSN will include the Session-Continue VSA set to “TRUE” in the
on-line Access Request messages.
If multiple flows are present for the session that hosted the Prepaid flow, and a prepaid flow was stopped,
and if it was the last flow for the session, then the session will be deleted by the PDSN. If one of mobile
IP flows expires and it is not the last flow for the session, then the PDSN will close the flow locally. If
the resource revocation mechanism is enabled on PDSN, the relevant resource revocation mechanism
will be applied in this case.
If the Simple IP (SIP) flow is closed (for example, a PPP session is torn down or quota for the SIP flow
expires), then all the other mobile IP flows, both prepaid and non-prepaid, will also get closed. If SIP
flow is closing due to allocated quota expiry, it will send Access Request message with Update-Reason
as “Quota Reached”. In other cases where the SIP session is closed, the Access Request will be sent with
Update-Reason as “Client Service Termination”. All other prepaid flows for the PPP session will also
send Access Request messages to close the prepaid service and return unused quota. The Update-Reason
for all these flows will contain value for “Main SI Released”.