Service utilization control manager

An apparatus is described for managing mobile network services. The apparatus includes a service authorization and utilization control function (SAUCF) element configured to authorize a mobile network service request by acting as a service manager configured to centrally coordinate service authorizations for multiple network services associated with an individual subscriber account by evaluating a service policy defining user access spanning the multiple network services. The service policy includes (a) communication authorization controls affecting permission for a user associated with the subscriber account to access a mobile network service in accordance with one or more criteria applicable to a bundled service category; and (b) charging controls for determining whether a subscriber account includes sufficient credits to use the mobile network service. A real time utilization interface is configured to transmit messages between the SAUCF element and a subscriber service utilization account.

BACKGROUND OF THE INVENTION

Mobile networks have evolved such that 3rd generation mobile networks offer many different services that include multimedia messaging, streaming video, parental control, and mobile phone advertisements. The IP Multimedia Subsystem (IMS) is an architectural framework for delivering internet protocol (IP) multimedia to mobile users. The 3GPP developed IMS to evolve mobile networks beyond GSM. IMS allows service providers to deliver Internet services over a variety of networks that include, but are not limited to, GPRS, Wireless LAN, CDMA2000, and fixed line.

To ease the integration with the Internet, IMS uses Internet protocols such as Session Initiation Protocol (SIP). The purpose of IMS is to aid access of multimedia and voice applications across wireless and wireline terminals. This is done by having a service plane and a bearer plane. The service plane provides different services to wireless terminals across wireless networks. Alternatively, the bearer plane allocates the physical network recourses (i.e. network bandwidth) necessary to provide the services provisioned by the service plane. Further, IMS has allowed Application Servers to apply policies for certain applications to the bearer plane via a functional element known as the Policy and Charging Rules Function (PCRF). The policy framework defined in IMS, for example, allows a subscriber to receive appropriate bandwidth and reductions in latency for viewing of a streaming video (service application). The IMS and MMD standards define how the PCRF is used by application servers (AS) to push or pull policy information about how a user is to use the resources provided by the bearer plane (RF and IP resources at the access network).

BRIEF SUMMARY OF THE INVENTION

Aspects of the invention allow mobile network users as well as mobile network providers to define policies that are managed across several applications and services. Thus, several application servers and network elements are coordinated to implement a service policy. More specifically, aspects of the invention define service level policies for any service be within an IMS based or non-IMS based wireless network implemented by SIP or non-SIP network elements.

A service policy is a set of rules that is applied when a subscriber uses a specific service (Web Browsing, Location, Presence, MMS, SMS, PoC, etc). The policy may be applicable on a per-need, per-subscriber basis. A service policy enhances or restricts use of the service functionality by the subscriber. In addition, a service level policy allows definition of service utilization rules that constrain how the service may be used by a subscriber. For example, a parent may restrict the use of her child's cell phone to only one hour per day between the time of 12 noon to 1 pm and 4 pm to 6 pm. Thus, aspects of the inventions allow mobile service subscribers to receive a level of customization for services rendered by a mobile network service provider. Further, mobile network service providers may provide not only custom service to subscribers but also simplifies the provisioning by allowing a single-point of configuration for subscriber based service control policies. Consequently, service level policies have wider scope than bearer level policies such as quality of service in the form of on-demand bandwidth, committed rates of throughput, committed reduction in delay/jitter/latency.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is an exemplary implementation of a system contemplated by an aspect of the invention is shown with reference to an IP multimedia network environment with an IMS enabled core. Note that aspects of the invention are not limited to the type of network depicted inFIG. 1, but may include other non-IMS networks.FIG. 1shows one exemplary environment where mobile services are managed on a per subscriber basis. In this aspect, a user device100is a mobile device, such as a wireless telephone or a portable computer capable of wireless communication with a plurality of radio access networks (102,104), such as those employing a CDMA-based, GSM-based, or a WCDMA-based standard.

To enhance the user experience with multimedia based services, the access networks (102,104) are connected to an IP Multimedia Subsystem (IMS) core network106that manages IP network sessions in a mobile environment. The IMS core network106further includes an application server (AS)108, which hosts one or more applications available to the mobile device100. The applications hosted by AS108include multimedia applications, such as streaming media applications, as well as other applications which require the maintenance of specific quality of service (QoS) guarantees. To expand the variety of applications available to the mobile device100via the access networks (102,104), the IMS core network106includes a connection to the public Internet110. Preferably, the mobile device100is a multi-mode entity capable of accessing a plurality of access networks operating based on different network technologies. Examples of a mobile device include but not limited to a mobile phone, Personal Digital Assistant (PDA), and a laptop computer.

FIG. 2illustrates an exemplary implementation of the IMS core network200and access networks (216,218) ofFIG. 1in more detail. The mobile device220and the application server202communicate via access networks (216,218) and the IMS core network200to establish and maintain a service session for an application launched by a user. In addition to the application server202, the IMS core network200includes other IMS functions, such as those described in G. Camarillo, M. Garcia-Martin, “The 3G IP Multimedia Subsystem (IMS) Merging The Internet And The Cellular Worlds,” John Wiley & Sons, Ltd., 2006 (second edition), which is incorporated herein by reference in its entirety for everything that it teaches. To this end, the AS202is connected to a Serving Call/Session Control Function (S-CSCF)204, which is a Session Initiation Protocol (SIP) server that performs session control, SIP registrar, authentication, and other IMS functions via SIP protocol signaling described in J. Rosenberg, H. Schulzrinne, G. Camarillo, A. Johnston, J. Peterson, R. Sparks, M. Handley, E. Schooler, “SIP: Session Initiation Protocol,” RFC 3261, IETF, June 2002, which is incorporated herein by reference in its entirety for everything that it teaches. The IMS core network200includes a number S-CSCFs, wherein each S-CSCF has a certain capacity in terms of a maximum number of supported mobile devices (MD)220.

The S-CSCF204, in turn, connects to a Proxy Call/Session Control Function (P-CSCF)206, which, among other IMS functions, includes user authentication functions and acts as an inbound and outbound SIP proxy server by relaying the SIP requests and responses to and from the mobile device220and to and from the IMS core network200. As with the S-CSCF204, the IMS core network200includes a number of P-CSCFs, wherein each P-CSCF has a certain capacity of being able to support a predefined number of mobile devices220. The Home Subscriber Server (HSS)208is a database of user-related information and contains user subscription data necessary for authentication and authorization of an IP multimedia session associated with a given application. The HSS serves the S-CSCF as shown inFIG. 2. The user subscription data is contained in a user profile that indicates, among other things, the types of services to which the user subscribes. Additionally, a Policy Function (PF)210This in the MMD (3GPP2 specs) is the “Policy and Charging Rule Function (PCRF) is used to authorize the media plane resources and supervise the QoS over the media plane by interfacing with a plurality of Access Gateways (212,214), which, in turn, allocate the access network resources within the corresponding access networks (216,218) in accordance with the QoS constraints required by the multimedia application. Note that the PF210is analogous to the Policy and Charging Rule Function (PCRF) in an MMD network architecture. Finally, the Home Agent (HA)215is a router typically involved in the Mobile IP (MIP) session registration process, as well as in tunneling of packets when the MD220is roaming.

FIG. 3illustrates an exemplary implementation of a service policy authorization and utilization control function (SAUCF)310that applies a service policy across several applications and services interacting with IMS and non-IMS network elements. Generally,FIG. 3shows a SAUCF interfacing with different network elements in the context of an IMS network. IMS application servers (AS1-ASn) (312,314) and the CSCF316utilize the services of the SAUCF310via the unique Service Authorization & Utilization Diameter Application (SAUDA) interface. The S-CSCF316plays an important part in Voice over IP calls because all calls for a given subscriber traverse the S-CSCF316. When no AS (312-314) is involved in a VOIP call, the S-CSCF316may request service level policies for a subscriber from the SAUCF.FIG. 3also shows legacy (non-IMS) application servers such as the MMSC318and a Web Proxy308. Legacy network elements also utilize the Service Authorization & Utilization Diameter Application interface to the SAUCF310to support service level policies. Finally, the services provided by the SAUCF310may be utilized by network elements other than application servers. For example,FIG. 3shows a firewall306communicating with the SAUCF310that may provide restriction or privacy services to a subscriber. Note that interfaces332-340carry the Service Authorization and Utilization Diameter Application.

FIG. 3also shows network elements and functions shown inFIG. 2that include the PCRF326and HSS324. The SAUCF also enforces subscriber level policies for access to the Web Servers304through the Internet302across a firewall306. Further, the CSCF316routes signaling for subscribers services to one or more mobile devices330through a plurality of Access Gateways (320-322). Note that interfaces344-350are on the User Plane and carry the data between the mobile and the servers (client-server) and or other mobiles (peer-to-peer). Interfaces360-362are Tx/Ty interfaces while interfaces356-358are Sh/Cx Diameter interfaces. In addition, interfaces352-354are SIP Signaling interfaces.

FIG. 4illustrates the details in an exemplary process of requesting authorization by a Network Element405to a SAUCF420. A Network Element (i.e. application server, firewall, etc.)405requests service authorization410from a SAUCF420. An SAUCF420may have several sub-functions that may include a Communication Authorization Sub-Function425, Access Authorization Sub-Function430, and a Charge Sub-Function435. Communication Authorization Sub-Function may include restrictions to certain members of a subscriber in terms of their call destination, calling minutes (time), usage, and content. For example, a family subscriber group may restrict a son's call destination to only his parents' mobile phones. Access Authorization Sub-Functions may include service access and privacy controls to certain members of a subscriber group. For example, a subscriber group may elect not to disclose to advertisers personal subscriber information for coupons on advertiser products and services. Charge Authorization Sub-Function checks the subscriber account to ensure that there are credits available to the subscriber use the requested service. The SAUCF Charging Authorization Sub-Function is used when a charging discount is applicable based on the fact that the subscriber is communicating (any form of communication) with members of the “trusted group.” For other forms of charging that do not involve the “trusted group” the SAUCF defers to the Online Charging System (SeeFIG. 5). After the SAUCF420determines whether to deny or authorize the requested service by the Network Element405, it sends a Service Authorization or Denial message415to the Network Element405.

FIG. 5illustrates an exemplary implementation of a SAUCF in network.FIG. 5shows two novel interfaces555and515and a unique subscriber specific data store with respect to managing mobile services on a subscriber basis. Note that the SAUCF may be implemented in any network element such as, but not limited to an AAA or a HSS. However, the SAUCF may also be implemented as a separate entity. The SAUCF510acts as a service manager for all services in the network between network elements for a subscriber group. With respect to the On Line Charging System (OCS)520the SAUCF may act as a charging proxy. Authorization requests555are sent by any network element (such as an application server)505to the SAUCF510. In addition, authorization requests may utilize the new “Service Authorization & Utilization Diameter Application” interface with Attribute Value Pair commands (AVPs) that will be described later in this specification. Charging based authorization requests may also be made by network elements as Credit Control Request (CCR) AVPs to describe the way a service is charged. In certain aspects of the invention, the SAUCF supports RFC 4006 (CCR/CCA) because the SAUCF may proxy for the OCS. The SAUCF510may pass charging requests to the OCS520in the form of a CCR Diameter messages. The SAUCF510may apply “trusted groups” discounts for subscribers that qualify. Trusted groups will be described in more details later in this specification.

FIG. 5also shows an application server505that communicates with a PCRF542across a Tx interface545and a PCRF542that communicates to an access gateway across a Ty interface550. Alternatively, the SAUCF510uses a Ru interface615and bypasses the OCS520for network elements that do not require charging authorization but require service level utilization authorization. The Ru interface515maps authorization messages555to service utilization messages sent to a Subscriber Service Utilization Account525. The OCS520communicates with the SAUCF510across a standard IMS Ro interface560.

The Ru interface515may use a modified Diameter application where the Diameter protocol is defined in RFC 3588. The Diameter Ru interface allows network elements to query the service usage credit balance for a given subscriber from the Subscriber Service Utilization Account525and provide the ability to withdraw and deposit into the balance. The “Subscriber Service Utilization Account”525allows definition of service utilization “buckets” based on “bundled services”. For instance, a “message bundled service” bucket for a subscriber has defined the category “messages” as MMS and SMS.FIG. 5also shows exemplary available subscriber service credits530. For example, the subscriber has service credits equal to 5 MMS/SMS messages, one hour of talk time using VOIP/PTT, and 10 MB of Browsing data.

FIG. 6is an exemplary SAUCF High Level Message flow chart. The Service Authorization and Utilization Control Function (SAUCF)610becomes a repository of subscriber service level policies. These policies are defined in Policy Decision Points such as the SAUCF610and enforced via Policy Enforcement Points such as an Application Server or Application Policy Function (network Element605).

SAUCF implements policies designed by a subscriber or subscriber group with regard to services provided to a subset of subscribers within a subscriber group. For example, a SAUCF incorporates a parental control service into its policy for a subscriber group. The parental controls include restricting all communication by children to only members of the family (father or mother). Further, parents may restrict their children to only 10 MMS or SMS messages per day between noon and 1 pm and 4 pm-6 pm. In addition parents may restrict children to voice services (such as VOIP or PTT) to only between noon and 1 pm and 4 pm-6 pm.

The SAUCF service policy may also contain rules for providing advertising services to a subscriber. For example, a subscriber may opt in for discounts or refunds by allowing reception of advertisement messages. For example, no more than 10 advertisement messages (MMS or SMS) per month. Further, SAUCF service policy may also contain rules for subscriber privacy. For example, a subscriber may opt in to disclose personal information to advertisers for a coupon/discount for given products. Subscriber may only allow no more than 10 personal location fixes or presence updates per month. In addition, the SAUCF may incorporate family charging services into its service policy for subscriber group. For example, all communication among members of the family is free, or all messages (MMS and SMS) send to members of the family is 50% off during evening hours.

As shown inFIG. 6, a first step is to determine if a subscriber is authorized to use a service is to send a “Service Access Request” message625to the SAUCF610. The network element605may use a Diameter protocol via a modified Diameter Application, namely a “Service Authorization & Utilization Diameter Application”. This modified diameter application is defined with a diameter application ID assigned by the Internet Assigned Numbers Authority (IANA). This Diameter application defines a set of additional attribute-value pairs (AVP) commands to describe the set of service policies desired by the subscriber. Table 1 below describes an exemplary set of additional Diameter AVPs that is supported by the Service Authorization & Utilization Diameter Application.

TABLE 1Command NameParametersDescriptionCommunication-RequestThis command requests communicationpermission between two end points.Source-AddressThis is the IP address associated with thesubscriber.Destination-AddressThis is the IP address associated with thedestination of any communicationoriginating from the Source-Address.ContentThis can be a “URL” or a Media Type suchas Audio and Video.Privacy-RequestThis command requests permission torelease to the requestor subscriber (target)specific data.RequestorIdentity of source of this request. Theidentity may be but not limited to: SIP-URI,MDN, MIN, Email-Address, IM Address,and NAI.TargetIdentity of target of this request. Theidentity may be but not limited to: SIP-URI,MDN, MIN, Email-Address, IM Address,and NAI.LocationRequestor is requesting “Location”information about Target. Locationinformation such as Latitude, Longitude,and Altitude.PresenceRequestor is requesting “Terminal Status”information about Target. The status maybe but not limited to Reachable,Unreachable, and Busy.IdentityRequestor is requesting personalinformation about the target. Identityinformation may be but not limited to FullName, Full Address, Mobile PhoneNumber, Email Address, SIP-URI, and IMAddress.Service-Authorization-This command requests permission to use aRequestparticular service identified by Service-IDand possibly includes the desired serviceutilization.RequestorIdentity of source of this request. Theidentity may be but not limited to: SIP-URI,MDN, MIN, Email-Address, IM Address,and NAI.Target-SubscriberIdentity of target of this request. Theidentity may be: SIP-URI, MDN, MIN,Email-Address, IM Address, and NAI.Target-Service-ContentURL used to identifies the content of aspecific service.Service-IDID identifying the specific service forwhich authorization is being requested.Example: MMS, LBS, PTT, etcUtilization-Request-TypeSpecifies the type of utilization request.Exemplary session based types may be:Initial-RequestUpdate-RequestFinal-RequestExemplary event based types may be:One-Time-EventRequested-Service-UnitsContains the amount “service” units desiredby the requestor. For example, for MMSRequested-Service-Units may be thenumber of MMS messages. Anotherexample may be a VOIP call where theRequested-Service-Units may be thenumber of minutes of conversation. Thisparameter forces a response containing the“Granted-Service-Units” AVP whichdefines the number of service units grantedby the SAUCF.Used-Service-UnitsContains the amount “service” unitsconsumed by the requestor.Identity-RequestSubscriber-AddressThis is the IP address associated with thesubscriber. If this subscriber has a live datasession for which the AAA has successfullyauthenticated this subscriber then theresponse to this command is the private-identifier known as Network AccessIdentifier (NAI) corresponding to thesubscriber. If no valid session exists for thissubscriber then the AAA returns an errorcode.Target-AddressThis is the IP address associated with thetarget of the subscriber communication. Ifthis target has a live data session for whichthe AAA has successfully authenticated thissubscriber then the response to thiscommand is the private-identifier known asNetwork Access Identifier (NAI)corresponding to the target. If no validsession exists for this target subscriber thenthe AAA returns an error code.Charge-RequestThis command is required for any chargeauthorization request and may includeCredit Control Diameter parametersdestined for the On Line Charging System.RequestorIdentity of source of this request. Theidentity may be but not limited to: SIP-URI,MDN, MIN, Email-Address, IM Address,and NAI.Charged-Service-IDID identifying the specific service forwhich charging is being requested.Example: MMS, LBS, PTT, etc.Any Additional AVPs inCredit Control Applicationas defined in RFC 4006“Credit ControlApplication”

As shown inFIG. 6, in a step1, a “Service Access Request” message is a subset of the Service Authorization & Utilization Diameter Application AVPs defined in Table 1. For example, when the SAUCF receives the Communication-Request AVP, the SAUCF then sends the Authentication, Authorization and Accounting (AAA) server615an Identity-Request, in a step2630, with the Subscriber-Address and Target-Address set to be the Source-Address and the Destination-Address, respectively. These parameters may have been previously received from a Communication-Request. The AAA615determines whether a valid data session exists for this subscriber/target and returns the Network Address Identifier (NAI) that uniquely identifies the subscriber and target to the operator network.

The service level policies defined in the Service Authorization and Utilization Control Function are bound to a given subscriber based on the NAI. The NAI is used in the SAUCF to bind subscribers to service policy rules associated with this subscriber. Further, each NAI in the SAUCF is also bound to a set of public-identities (aliases) associated with this subscriber as shown inFIG. 7. The following minimal aliases are defined but are not exhaustive SIP-URI, MDN, MIN, Email Address, and Instant Message Address.

Each subscriber in the SAUCF is bound to a “trusted group” of subscribers defined inFIG. 7. Each subscriber is also identified via NAIs and aliases. Service policy rules govern the binding between a given subscriber and the trusted group as shown inFIG. 7. In a step3(635) ofFIG. 6the SAUCF using the NAI for this subscriber, retrieves his/her aliases and also other aliases of the trusted group. The SAUCF then proceeds to apply the service policy rules620.

FIG. 7illustrates that each subscriber is bound to a “trusted group” of subscribers. Each subscriber is also identified via NAIs and aliases. Service policy rules govern the binding between a given subscriber and the trusted group. For example, a trusted group710may be the mother715and father720of a subscriber group. A son705is bound by the service rules imposed by the mother715and father720. An exemplary service rule may be that the son may only call mother and father and no one else. Thus, if the son705requests to call another person, then the SAUCF implements the service rule and denies the request to the son.

FIGS. 8-11are flow charts that illustrate an exemplary application of service policy rules. A first set of steps may be to apply communication service rules. For example, a son may be restricted to call only his parents. Consequently, at a first step805, a SAUCF may match the Target NAI against the Subscriber Trusted Group (parents) NAIs. If a match is not found then service access is denied820as shown in step4.b645inFIG. 6. If a match is found, then the SAUCF may match the allowed communication times by the requesting subscriber with the requesting time of the subscriber at a step810. If a match is not found then service access is denied820as shown in step4.b645inFIG. 6. For example, if the requesting subscriber is a son who is calling his mother at 3 pm but is only allowed to call his parents between 5 pm and 7 pm, then service access is denied to him. At a next step815, a SAUCF matches the requested content against the disallowed content for the subscriber. If a match is found (content disallowed) then service access is denied820as shown in step4.b645inFIG. 6. For example, if a subscriber requests streaming video from a particular website, and the trusted group has assigned the particular website as disallowed content, and then the subscriber is denied service820. However, if a match is not found, the SAUCF may continue by applying Security and Privacy Service rules825.

At a next step905, the SAUCF determines whether to apply Security and Privacy rules based on whether a Privacy Request AVP is present (See Table 1). It may then match the Location, Presence, or Identity parameter against the setting for the subscriber's trusted group. If a match is found then service access is denied920as shown in step4.b645inFIG. 6. Next, the SAUCF may apply Service Authorization and Utilization rules. At a next step910, the SAUCF matches the Service ID against the Service ID allowed for the subscriber. If a match is found and the Target Service Content parameter is present (See Table 1), then the SAUCF matches the Target Service Content against the disallowed content for the subscriber at a next step915. If a match is found then service access is denied920as shown in step4.b645inFIG. 6. However, if a match is not found the SAUCF may continue to apply further service authorization and utilization rules925.

A set of steps1005-1025apply further exemplary service authorization and utilization rules. At a next step1005, the SAUCF applies service utilization bonuses if it determines that the subscriber has not exceeded its service utilization quota. For example, if a Charging Request is present and a Charged Service ID does not match the Service ID, then the SAUCF checks if the Requested-Service-Units parameter (See Table 1) is present and a charge discount is applicable. If so, then a bonus is applied. Note that checking whether the Charging Request is present and a Charged Service ID does not match the Service ID shows that the SAUCF is a proxy for the OCS and that any charging requests are handled by the OCS. Further, it ensures that the “Subscriber Service Utilization Account” is accessed by either the SAUCF or the OCS but not both. At a next step1010, if the Requested Service Units or Used Service Unit AVP are present (See Table 1) then they are mapped to the Ru interface as shown inFIG. 12to send to the Subscriber Service Utilization Account. At a next step1015, the SAUCF determines whether the Subscriber Service Utilization Account can satisfy the requested service. If not, then the requested service is denied1020. If so, then the SAUCF may apply “Trusted Group” charge service rules1025.

A set of steps1105-1120implement exemplary “Trusted Group” charge service rules. At a next step1105, the SAUCF determines whether a “Trusted Group” charge discount is applicable. At a next step1110, the SAUCF then applies the discount. At a next step1115, the request message is forwarded to the OCS. At a next step1125, the service is allowed as shown in Step4.a(640) inFIG. 7.

As discussed previously, the Ru (Real Time Utilization) interface is a modified Diameter application that allows network elements to query the service usage credit balance (held in a network element called the “Subscriber Service Utilization Account”) for a given subscriber, and provide the ability to withdraw and deposit into the balance. The “Subscriber Service Utilization Account” allows definition of service utilization “buckets” based on “bundled services”. For instance, a “message bundled service” bucket for a subscriber has messages defined as MMS and SMS.

The table below describes a modified set of Diameter AVP commands that may be supported by the Real Time Service Utilization Diameter application.

FIG. 12shows the service utilization messages received by the SAUCF are mapped to the Ru Interface. The Ru interface is between the SAUCF1205and the Subscriber Service Utilization Account1210. For example, a Service Authorization Request and a Requested Service Units message1215received by the SAUCF1205are mapped to the Ru interface as a Service Utilization Withdrawal message1220to the Subscriber Service Utilization Account1210. Another example is that a Service Authorization Request and a Used Service Units message1225received by the SAUCF are mapped to the Ru interface as a Service Utilization Deposit message1230to the Subscriber Service Utilization Account1210.

FIG. 13is a flow chart illustrating an exemplary application of service utilization bonuses. Discounts may be defined in the SAUCF as part of the charging rules. Discounts in the SAUCF apply both to the price of the service as well as the number of units utilized for that service. For the number of units utilized for that service the discount becomes a cumulative bonus. For example, sending an MMS message may cost 10 cents and sending MMS messages to members of the family produces a 50% discount. Then sending the first MMS message costs 5 cents and sending the second also costs 5 cents but the subscriber has gained an additional MMS message as a bonus. That is, the subscriber sent two MMS messages but consumed only one. Note that the SAUCF accumulates bonuses on a per service basis. So if the 50% discount continues to apply and the subscriber sends 2 MMS messages and 2 SMS messages than the subscriber will only have consumed one MMS and one SMS messages, respectively. The SAUCF may need to maintain a per-subscriber, per-service counter called a Service-Units-Bonus to support the cumulative bonus for service unit discounts as shown inFIG. 13. At a step1305. a Service-Units-Bonus counter is initialized with a value of zero (0%) units for this subscriber for this service. Each time a service unit is consumed the discount is applied. A service unit may be considered consumed when a one time service utilization or charging event is received (1310) or when a service session is over (1315). Thus, at a step1302, the SAUCF determines whether a completed service unit has been consumed. If so then it applies the bonus at a step1325, for example, Service-Units-Bonus=Service-Units-Bonus+Discount-Rate. At a step1330the SAUCF sets the value of “Service-Utilization-Deposit” to zero. At a step1335the SAUCF determines whether Service-Units-Bonus greater than or equal to 100%. If so, then at a step1340value of “Service-Utilization-Deposit” is incremented by 1 unit. At step1345, Service-Units-Bonus=Service-Units-Bonus−100%. However, if Service-Units-Bonus is less than 100%, then the SAUCF sends a “Service-Utilization-Deposit” to the Subscriber Service Utilization Account at step1350.

A service unit is consumed when a one time service utilization or charging event occurs or when a service session is over. A one time service utilization or charging event may be the following: (a) A Service-Authorization-Request AVP with a Requested-Service-Units AVP is received by the SAUCF and the unit-type is (a) One-Time-Event; or (b) A Credit Control (RFC4006) request with “Event-Request” AVP is received. A service session is over when the following occurs: (a) the SAUCF keeps track of units consumed for Service-Authorization-Requests by tracking the “Granted-Service-Units” returned by the Subscriber Service Utilization Account; (b) the SAUCF keeps track of chargeable consumed units by tracking the “Granted-Units” returned by the On Line Charging System; (c) a service session is over when a Service-Authorization-Request AVP with a Requested-Service-Units AVP is received by the SAUCF and the unit-type is Final-Request and “Used-Service-Units” AVP; and (d) a chargeable service session is over when a Credit Control message is received with a request type of “Terminate” and Used-Units. Note that time constraints may also be included in the calculation of the discount. For example, time constraints may indicate when discounts apply.

The SAUCF may also apply charging discounts to a subscriber for being a member of Trusted Groups. The SAUCF may apply special discounts that cover multiple services tied to certain communication constraints such as the constraint of communication within a “trusted group”. This is not possible by utilizing an On Line Charging System (OCS) alone. An exemplary application of Trusted-Group discounts may be that the SAUCF on receipt of a Charge-Request AVP may do the following: (1) retrieve the price for this service from the OCS; (2) send a Credit Control message with Price-Inquiry AVP to the OCS for this Charged-Service-ID; (3) apply the Trusted-Group discount for this subscriber using price returned in the Credit Control Answer message; (4) Compute Discount=Service Price*Trusted Group Discount Rate; and (5) send a Credit Control message with Refund AVP which reflects the Discount: