5.2 Online charging scenarios
32.2993GPPCharging managementDiameter charging applicationsRelease 17Telecommunication managementTS
5.2.0 Introduction
Online charging for both events and sessions between CTF and the OCF is performed using the Ro reference point. The Ro reference point supports integrity protection and authentication for the case that the CTF is outside the operator domain.
5.2.1 Basic principles
There are two sub-functions for online charging that affect online charging principles and require a more detailed description: rating and unit determination. Both rating and unit determination can be implemented centralized, i.e. on the OCF, or decentralized, that is, on the CTF.
Unit determination refers to the calculation of the number of non-monetary units (service units, data volume, time and events) that shall be assigned prior to starting service delivery.
– With Centralized Unit Determination, the OCF determines the number of non-monetary units that a certain service user can consume based on a service key received from the CTF.
– With the Decentralized Unit Determination approach, the CTF determines itself how many units are required to start service delivery, and requests these units from the OCF.
After checking the service user’s account balance, the OCF returns the number of granted units to the CTF. The CTF is then responsible for the supervision of service delivery. Particularly, the CTF shall limit service delivery to the corresponding number of granted units.
Rating refers to the calculation of a price out of the non-monetary units calculated by the unit determination function.
– With the Centralized Rating approach, the CTF and the OCF exchange information about non-monetary units. The OCF translates these units into monetary units.
– With the Decentralized Rating approach, the corresponding rating control is performed within the CTF. Consequently, CTF and OCF exchange information about monetary units.
Three cases for online charging can be distinguished: Immediate Event Charging (IEC), Event Charging with Unit Reservation (ECUR) and Session Charging with Unit Reservation (SCUR). These cases are further described in TS 32.240 [1].
5.2.2 Charging scenarios
5.2.2.0 Introduction
In order to perform event charging via Ro, the scenarios between the involved entities UE-A, OCF and CTF need to be defined. The charging flows shown in this subclause include scenarios with immediate event charging and event charging with reservation. In particular, the following cases are shown:
1 Immediate Event Charging
a) Decentralized Unit Determination and Centralized Rating
b) Centralized Unit Determination and Centralized Rating
c) Decentralized Unit Determination and Decentralized Rating
2 Event charging with Unit Reservation
a) Decentralized Unit Determination and Centralized Rating
b) Centralized Unit Determination and Centralized Rating
c) Decentralized Unit Determination and Decentralized Rating
3 Session charging with Unit Reservation
a) Decentralized Unit Determination and Centralized Rating
b) Centralized Unit Determination and Centralized Rating
c) Decentralized Unit Determination and Decentralized Rating
The combination of Centralized Unit Determination with Decentralized Rating is not possible.
5.2.2.1 Immediate Event Charging (IEC)
5.2.2.1.1 Decentralized Unit Determination and Centralized Rating
In scenario figure 5.2.2.1.1.1, CTF asks the OCF to assign a defined number of units.
Figure 5.2.2.1.1.1: IEC – Centralized Rating and Decentralized Unit Determination
1) Request for resource usage: UE-A requests the desired resource from the Network Element.
2) Units Determination: depending on the requested service the CTF determines the number of units accordingly.
3) Debit Units Request: the CTF requests the OCF to assign the defined number of units.
4) Rating Control: assisted by the rating entity the OCF calculates the number of monetary units that represents the price for the number of units determined in item 2.
5) Account Control: provided that the user’s credit balance is sufficient, the OCF triggers the deduction of the calculated amount from the subscriber’s account.
6) Debit Units Response: the OCF informs the CTF of the number of granted units.
7) Content/Service Delivery: the CTF delivers the content/service at once, in fractions or in individually chargeable items, corresponding to the number of granted units.
8) Credit Unit Control (cont.): this function block is optional and a replication of items 2 to 6.
9) Content/Service Delivery (cont.): the continuation of content delivery occurs in correspondence with the occurrence of item 8.
10) Session released: Session is released.
5.2.2.1.2 Centralized Unit Determination and Centralized Rating
In scenario figure 5.2.2.1.2.1, CTF asks the OCF to assign units based on the service key specified by the CTF.
Figure 5.2.2.1.2.1: IEC – Centralized Rating and Centralized Unit Determination
1) Request for resource usage: The UE-A requests the desired resource or content from the Network Element.
2) Debit Units Request: depending on the service requested by the UE-A, the CTF determines the service key and forwards the Debit Units Request with service key to the OCF.
3) Units Determination: the OCF determines the number of non-monetary units needed for the content/service delivery, based on the received service key.
4) Rating Control: assisted by the rating entity the OCF calculates the number of monetary units that represent the price for the number of units determined in item 3.
5) Account Control: provided that the user’s credit balance is sufficient, the OCF triggers the deduction of the calculated amount from the subscriber’s account.
6) Debit Units Response: the OCF informs the CTF of the number of granted units. This includes the case where the number of units granted indicates the permission to render the service that was identified by the received service key.
7) Content/Service Delivery: the CTF delivers the content/service at once, in fractions or in individually chargeable items, corresponding to the number of granted units.
8) Credit Service Control (cont.): this function block is optional and a replication of items 2 to 6.
9) Content/Service Delivery (cont.): the continuation of content delivery occurs in correspondence with the occurrence of item 8.
10) Session released: the session is released.
5.2.2.1.3 Decentralized Unit Determination and Decentralized Rating
In scenario figure 5.2.2.1.3.1, the CTF asks the OCF to assure the deduction of an amount of the specified number of monetary units from the subscriber’s account.
Figure 5.2.2.1.3.1: IEC – Decentralized Rating and Decentralized Unit Determination
1) Request for resource usage: The UE-A requests the desired content from the Network Element.
2) Units Determination: depending on the service requested by the UE-A, the CTF determines the number of units accordingly.
3) Rating Control: the CTF calculates the number of monetary units that represent the price for the number of units determined in item 2.
4) Debit Units Request: the CTF requests the OCF to assure the deduction of an amount corresponding to the calculated number of monetary units from the subscriber’s account.
5) Account Control: provided that the user’s credit balance is sufficient, the OCF triggers the deduction of the calculated amount from the subscriber’s account.
6) Debit Units Response: the OCF indicates to the CTF the number of deducted monetary units.
7) Content/Service Delivery: the CTF delivers the content/service at once, in fractions or in individually chargeable items, corresponding to the number of units as specified in items 2 and 3.
8) Credit Amount Control (cont.): this function block is optional and a replication of items 2 to 6.
9) Content/Service Delivery (cont.): the continuation of content delivery occurs in correspondence with the occurrence of item 8.
10) Session released: the session is released.
5.2.2.1.4 Further options
In addition to the flows that are specified in the previous subclauses, the Debit Unit operation may alternatively be carried out concurrently with service delivery, or after completion of service delivery.
5.2.2.2 Event Charging with Unit Reservation (ECUR)
5.2.2.2.1 Decentralized Unit Determination and Centralized Rating
In scenario figure 5.2.2.2.1.1, the CTF requests the reservation of units prior to service delivery.
An account debit operation is carried out following the conclusion of service delivery.
Figure 5.2.2.2.1.1: ECUR – Decentralized Unit Determination and Centralized Rating
1) Request for resource usage: The UE-A requests the desired content/service from the NE.
2) Units Determination: depending on the requested service the CTF determines the number of units accordingly.
3) Reserve Units Request: the CTF requests the OCF to reserve the number of units determined in item 2.
4) Rating Control: assisted by the rating entity the OCF calculates the number of monetary units that represents the price for the number of units determined in item 2.
5) Account Control: the OCF checks whether the user’s account balance is sufficient for the requested reservation.
6) Reservation Control: if the user’s account balance is sufficient then the corresponding reservation is made.
7) Reserve Units Response: the OCF informs the CTF of the reserved number of units.
8) Reserved Units Supervision: simultaneously with the service delivery, the CTF monitors the consumption of the reserved units.
9) Content/Service Delivery: the CTF delivers the content/service at once, in fractions or in individually chargeable items, corresponding to the reserved number of units.
10) Debit Units Request: the CTF requests the OCF to assure the deduction of an amount corresponding to the consumed number of units from the subscriber’s account. In the case that no further units are required for this service, an appropriate indication triggering the release of the remaining reservation is given.
11) Rating Control: assisted by the rating entity the OCF calculates the number of monetary units to deduct from the subscriber’s account.
12) Account Control: the OCF triggers the deduction of the calculated amount from the subscriber’s account.
13) Debit Units Response: the OCF informs the CTF of the actually deducted units.
14) Session Release: the session is released.
5.2.2.2.2 Centralized Unit Determination and Centralized Rating
In scenario figure 5.2.2.2.2.1, the CTF requests the OCF to reserve units based on the service key specified by the CTF. An account debit operation is carried out following the conclusion of service delivery.
Figure 5.2.2.2.2.1: ECUR – Centralized Unit Determination and Centralized Rating
1) Request for resource usage: The UE-A requests the desired content from the CTF.
2) Reserve Units Request: depending on the service requested by the UE-A, the CTF determines the service key and forwards the Reserve Units Request with service key to the OCF.
3) Units Determination: the OCF determines the number of non-monetary units needed for the content/service delivery, based on the received service key.
4) Rating Control: assisted by the rating entity the OCF calculates the number of monetary units that represent the price for the number of units determined in item 3.
5) Account Control: the OCF checks whether the user’s account balance is sufficient for the requested reservation.
6) Reservation Control: if the user’s account balance is sufficient, then the corresponding reservation is made.
7) Reserve Units Response: the OCF informs the CTF of the reserved number of units. This includes the case where the number of units reserved indicates the permission to render the service that was identified by the received service key.
8) Granted Units Supervision: simultaneously with the service delivery, the CTF monitors the consumption of the reserved units.
9) Content/Service Delivery: the CTF delivers the content/service at once, in fractions or in individually chargeable items, corresponding to the reserved number of units.
10) Debit Units Request: the CTF provides according to previous Reserve Units Response the request to deduct the amount of units corresponding to the consumed number of units.
11) Rating Control: assisted by the rating entity the OCF calculates the number of monetary units to deduct from the subscriber’s account.
12) Account Control: the OCF triggers the deduction of the calculated amount from the subscriber’s account.
13) Debit Units Response: the OCF informs the CTF of the actually deducted units.
14) Session Released: the session is released.
5.2.2.2.3 Decentralized Unit Determination and Decentralized Rating
In scenario figure 5.2.2.2.3.1, the CTF request the OCF to assure the reservation of an amount of the specified number of monetary units from the subscriber’s account. An account debit operation that triggers the deduction the amount from the subscriber’s account is carried out following the conclusion of service delivery.
Figure 5.2.2.2.3.1: ECUR – Centralized Unit Determination and Centralized Rating
1) Request for resource usage: The UE-A requests the desired content from the CTF.
2) Units Determination: depending on the service requested by the UE-A, the CTF determines the number of units accordingly.
3) Rating Control: the CTF calculates the number of monetary units that represent the price for the number of units determined in item 2.
4) Reserve Units Request: the CTF requests the OCF to assure the reservation of an amount corresponding to the calculated number of monetary units from the subscriber’s account.
5) Account Control: the OCF checks whether the user’s account balance is sufficient for the requested reservation.
6) Reservation Control: if the user’s credit balance is sufficient, then the corresponding reservation is made.
7) Reserve Units Response: the OCF informs the CTF of the reserved number of monetary units.
8) Budget Control: simultaneously with the service delivery, the CTF monitors the consumption of the granted amount.
9) Content/Service Delivery: the CTF delivers the content/service at once, in fractions or in individually chargeable items, corresponding to the number of units.
10) Debit Units Request: the CTF requests the OCF to assure the deduction of an amount corresponding to the consumed number of monetary units from the subscriber’s account.
11) Account Control: the OCF triggers the deduction of the consumed amount from the subscriber’s account.
12) Debit Units Response: the OCF indicates to the CTF the number of deducted monetary units.
13) Session Released: the session is released.
5.2.2.3 Session charging with Reservation
5.2.2.3.1 Decentralized Unit Determination and Centralized Rating
In scenario figure 5.2.2.3.1.1, the CTF requests the reservation of units prior to session supervision. An account debit operation is carried out following the conclusion of session termination.
Figure 5.2.2.3.1.1: SCUR – Decentralized Unit Determination and Centralized Rating
1) Request for resource usage: The UE-A requests session establishment from the CTF.
2) Units Determination: depending on the requested type of the session the CTF determines the number of units accordingly.
3) Reserve Units Request: the CTF requests the OCF to reserve the number of units determined in item 2
4) Rating Control: assisted by the rating entity the OCF calculates the number of monetary units that represents the price for the number of units determined in item 2.
5) Account Control: the OCF checks whether the user’s account balance is sufficient for the requested reservation.
6) Reservation Control: if the user’s account balance is sufficient then the corresponding reservation is made.
7) Reserve Units Response: the OCF informs the CTF of the reserved number of units.
8) Reserved Units Supervision: simultaneously with the ongoing session, the CTF monitors the consumption of the reserved units.
9) Session ongoing: the CTF maintains the session. One or more debit and reserve operations may be performed when the session is ongoing.
10) Session Release: the session is released
11) Debit Units Request: the CTF requests the OCF to assure the deduction of an amount corresponding to the consumed number of units from the subscriber’s account.
12) Rating Control: assisted by the rating entity the OCF calculates the number of monetary units to deduct from the subscriber’s account.
13) Account Control: the OCF triggers the deduction of the calculated amount from the subscriber’s account.
14) Debit Units Response: the OCF informs the CTF of the actually deducted units.
5.2.2.3.2 Centralized Unit Determination and Centralized Rating
In scenario figure 5.2.2.3.2.1, the CTF requests the OCF to reserve units based on the service key specified by the CTF. An account debit operation is carried out following the conclusion of session.
Figure 5.2.2.3.2.1: SCUR – Centralized Unit Determination and Centralized Rating
1) Request for resource usage: The UE-A requests the session establishment from the CTF.
2) Reserve Units Request: depending on the requested type of the session by the UE-A, the CTF determines the service key identifier and forwards the Reserve Un with service key its Request to the OCF.
3) Units Determination: the OCF determines the number of non-monetary units needed for the content/service delivery, based on the received service key.
4) Rating Control: assisted by the rating entity the OCF calculates the number of monetary units that represent the price for the number of units determined in item 3.
5) Account Control: the OCF checks whether the user’s account balance is sufficient for the requested reservation.
6) Reservation Control: if the user’s account balance is sufficient, then the corresponding reservation is made.
7) Reserve Units Response: the OCF informs the CTF of the reserved number of units. This includes the case where the number of units reserved indicates the permission to render the service that was identified by the received service key.
8) Granted Units Supervision: simultaneously with the ongoing session, the CTF monitors the consumption of the reserved units.
9) Session ongoing: the CTF maintains the session. One or more debit and reserve operations may be performed when the session is ongoing.
10) Session Released: the session is released.
11) Debit Units Request: the CTF requests the OCF to assure the deduction of an amount corresponding to the consumed number of units from the subscriber’s account
12) Rating Control: assisted by the rating entity the OCF calculates the number of monetary units to deduct from the subscriber’s account.
13) Account Control: the OCF triggers the deduction of the calculated amount from the subscriber’s account.
14) Debit Units Response: the OCF informs the CTF of the actually deducted units.
5.2.2.3.3 Decentralized Unit Determination and Decentralized Rating
In scenario figure 5.2.2.3.3.1, the CTF request the OCF to assure the reservation of an amount of the specified number of monetary units from the subscriber’s account. An account debit operation that triggers the deduction the amount from the subscriber’s account is carried out following the conclusion of session establishment.
Figure 5.2.2.3.3.1: SCUR – Decentralized Unit Determination and Decentralized Rating
1) Request for resource usage: The UE-A requests the session establishment from the CTF.
2) Units Determination: depending on the requested type of the session by the UE-A, the CTF determines the number of units accordingly.
3) Rating Control: the CTF calculates the number of monetary units that represent the price for the number of units determined in item 2.
4) Reserve Units Request: the CTF requests the OCF to assure the reservation of an amount corresponding to the calculated number of monetary units from the subscriber’s account.
5) Account Control: the OCF checks whether the user’s account balance is sufficient for the requested reservation.
6) Reservation Control: if the user’s credit balance is sufficient, then the corresponding reservation is made.
7) Reserve Units Response: the OCF informs the CTF of the reserved number of monetary units.
8) Budget Control: simultaneously with the ongoing session, the CTF monitors the consumption of the granted amount.
9) Session ongoing: the CTF maintains the session. One or more debit and reserve operations may be performed when the session is ongoing.
10) Session Released: the session is released.
11) Debit Units Request: the CTF requests the OCF to assure the deduction of an amount corresponding to the consumed number of monetary units from the subscriber’s account.
12) Account Control: the OCF triggers the deduction of the consumed amount from the subscriber’s account.
13) Debit Units Response: the OCF indicates to the CTF the number of deducted monetary units.
5.2.3 Basic operations
Online Credit-Control uses two basic logical operations: Debit Units and Reserve Units.
– "Debit Units Request"; sent from CTF OCF
After receiving a service request from the subscriber, the CTF sends a Debit Units Request to the OCF.
The CTF may either specify a service key (centralised unit determination) or the number of units requested (decentralised unit determination).
For refund purpose, the CTF sends a Debit Units Request to the OCF as well.
– "Debit Units Response"; sent from OCF CTF
The OCF replies with a Debit Units Response, which informs the CTF of the number of units granted as a result of the Debit Units Request. This includes the case where the number of units granted indicates the permission to render the requested service.
For refund purpose, the OCF replies with a Debit Units Response.
– "Reserve Units Request"; sent from CTF OCF
Request to reserve a number of units for the service to be provided by an CTF. In case of centralized unit determination, the CTF specifies a service key in the Reserve Unit Request, and the OCF determines the number of units requested. In case of decentralised unit determination, the number of units requested is specified by the CTF.
– "Reserve Units Response"; sent from OCF CTF
Response from the OCF which informs the CTF of the number of units that were reserved as a result of the "Reserve Units Request".
IEC uses the Direct Debiting One Time Event procedure specified in RFC 4006 [402] and therefore is performed by the use of the logical "Debit Units" operation, as specified in clause 6.3.3.
SCUR and ECUR use both the "Debit Units" and "Reserve Units" operations.
SCUR uses the Session Based Credit-Control procedure specified in RFC 4006 [402]. In session charging with unit reservation, when the "Debit Units" and "Reserve Units" operations are both needed, they shall be combined in one message, as specified in clause 6.3.5.
For SCUR and ECUR the consumed units are deducted from the subscriber’s account after service delivery.
Thus, the reserved and consumed units are not necessarily the same. Using this operation, it is also possible for the CTF to modify the current reservation, including the return of previously reserved units.
Table 5.2.3.1 and table 5.2.3.2 describe the content of these operations.
Table 5.2.3.1: Debit / Reserve Units Request content
|
Information Element |
Category |
Description |
|---|---|---|
|
Session Identifier |
M |
This field identifies the operation session. |
|
Originator Host |
M |
This field contains the identification of the source point of the operation. |
|
Originator Domain |
M |
This field contains the realm of the operation originator. |
|
Destination Domain |
M |
This field contains the realm of the operation destination. |
|
Operation Identifier |
M |
This field is a unique operation identifier. |
|
Operation Token |
M |
This field contains the service identifier. |
|
Operation Type |
M |
This field defines the transfer type: event for event based charging and start, interim, stop for session based charging. |
|
Operation Number |
M |
This field contains the sequence number of the transferred messages. |
|
Destination Host |
OC |
This field contains the identification of the destination point of the operation. |
|
User Name |
OC |
This field contains the identification of the user. |
|
Origination State |
OC |
This field contains the state associated to the source point of the operation. |
|
Origination Timestamp |
OC |
This field contains the time when the operation is requested. |
|
Subscriber Identifier |
OM |
This field contains the identification of the mobile subscriber (i.e. MSISDN) or the fixed user (i.e. fixed device or residential gateway ) that uses the requested service. |
|
Termination Cause |
OC |
This field contains the termination reason of the service. |
|
Requested Action |
OC |
This field contains the requested action. |
|
AoC Type |
OC |
This field denotes if AoC Information is requested and what type of information is needed. |
|
Multiple Operation |
OM |
This field indicate the occurrence of multiple operations. |
|
Multiple Unit Operation |
OC |
This field contains the parameter for the quota management. |
|
Operation Correlation Identifier |
OC |
This field contains information to correlate messages generated for different components of the service. |
|
Subscriber Equipment Number |
OC |
This field contains the identification of the mobile device (i.e. IMEI) that uses the subscriber. |
|
Proxy Information |
OC |
This field contains the parameter of the proxy. |
|
Route Information |
OC |
This field contains the parameter of the route. |
|
Service Information |
OM |
This parameter holds the individual service specific parameters as defined in the corresponding ‘middle tier’ TS. |
Table 5.2.3.2: Debit / Reserve Units Response content
|
Information Element |
Category |
Description |
|---|---|---|
|
Session Identifier |
M |
This field identifies the operation session. |
|
Operation Result |
M |
This field identifies the result of the operation. |
|
Originator Host |
M |
This field contains the identification of the source point of the operation. |
|
Originator Domain |
M |
This field contains the realm of the operation originator. |
|
Operation Identifier |
M |
This field is a unique operation identifier. |
|
Operation Type |
M |
This field defines the transfer type: event for event based charging and start, interim, stop for session based charging. |
|
Operation Number |
M |
This field contains the sequence number of the transferred messages. |
|
Operation Failover |
OC |
This field contains an indication to the CTF whether or not a failover handling is to be used when necessary. |
|
Multiple Unit Operation |
OC |
This field contains the parameter for the quota management. |
|
Cost Information |
OC |
This field contains the cost information of the service. |
|
Low Balance Indication |
OC |
This field indicates whether the subscriber account balance went below a designated threshold set by his account. |
|
Remaining Balance |
OC |
This field contains the remaining balance of the subscriber. |
|
Operation Failure Action |
OC |
For Credit-Control sessions the content of this field enables the credit-control client to decide what to do if sending credit-control messages to the credit-control server has been temporarily prevented. |
|
Operation Event Failure Action |
OC |
For one time event direct debiting the content of this field enables the credit-control client to decide what to do if sending credit-control messages to the credit-control server has been temporarily prevented. |
|
Redirection Host |
OC |
This field contains the host the request should be forwarded to. |
|
Redirection Host Usage |
OC |
This field identifies the routing entry resulting from the Redirect-Host is to be used. |
|
Redirection Cache Time |
OC |
This field contains the maximum number of seconds the peer and route table entries, created as a result of the Redirect-Host, will be cached. |
|
Proxy Information |
OC |
This field contains the parameter of the proxy. |
|
Route Information |
OC |
This field contains the parameter of the route. |
|
Failed parameter |
OC |
This field contains missing and/or unsupported parameter that caused the failure. |
|
Service Information |
OC |
This parameter holds the individual service specific parameters as defined in the corresponding ‘middle tier’ TS. |