Adaptive Charging Accounting and Billing system ... - Semantic Scholar

0 downloads 0 Views 140KB Size Report
(MMS) and value added services (VAS). The introduction of IP based services will enable the creation of an open market, with a large number of independent ...
Adaptive Charging Accounting and Billing system for the support of advanced business models for VAS provision in 3G systems Maria Koutsopoulou, Nancy Alonistioti, Evangelos Gazis, Alexandros Kaloxylos National and Kapodistrian University of Athens, School of Sciences, Department of Informatics and Telecommunications, Communication Networks Laboratory, 157 84 Athens, Greece emails: {mkoutsop | nancy | gazis | agk}@di.uoa.gr

ABSTRACT In the framework of the design of a flexible service provision platform for 3G systems and beyond, an integrated system for enabling advanced Charging, Accounting and Billing has been introduced. The CAB system is adaptive to VAS charging requirements and network/business environment concepts. Part of the system has been developed in the frame of IST-MOBIVAS project1. I.

INTRODUCTION

rd With the evolution of 3 generation mobile communications, new challenges are imminent both for network providers and independent service providers. The evolution of UMTS, which combines the IP world with the telecommunication services, is leading to innovative new products and services, such as multimedia message services (MMS) and value added services (VAS). The introduction of IP based services will enable the creation of an open market, with a large number of independent Value Added Service Providers (VASPs), who will deploy their services through a limited number of UMTS network providers. This is also a challenge for the mobile operators to increase their revenue. The service provision in 2G systems is tightly coupled with the mobile operator. In the currently proposed business models a user has typically subscriptions with a mobile operator and a number of Value Added Service Providers (VASPs). The user receives several separate bills: one from the operator that charges the volume of traffic the user transfers through the network (or the duration one 1

This work was partially supported by the IST project MOBIVAS (IST-1999-10206, web home page http://mobivas.cnl.di.uoa.gr.) The content of this paper expresses solely the opinion of the authors.

is connected to it), and the others from the VASPs that charge usually based on a monthly subscription fee. Contrary to the existing approaches, there is an increasing demand for more flexible and adaptable service provision to mobile users without additional contracts and subscriptions with the independent VASPs, as well as the generation of only one itemised bill for all services [1]. This evolution creates new aspects to be addressed. Charging2, accounting3 and billing4 are certainly very important aspects for service provision, since the advanced business models to be adopted, produce a completely new scene for the involved players. Existing protocol standards limit the operator in deploying flexible billing schemes. Moreover, the VASPs are required to use additional functionality to monitor the exchanged traffic and issue fair bills for the users. In order to tackle the aforementioned problems we propose in this paper, an integrated system named CAB (Charging, Accounting and Billing System) that has the overall control for the charging, accounting and billing under the administrative domain of a third trusted party. Since mobile operators have a significant part of the required equipment, it is possible that the operator could also act as a third trusted party between the users and the VASPs, resulting that the user will receive only one itemized bill for all services. Specific extensions in the existing components’ functionality are necessary. In addition, there is need for open generic interfaces between the CAB, 2

Charging is the function whereby data exchange information is processed in order to determine the usage for which the user will be billed. 3 Accounting is the process of revenue sharing amongst operators in case of roaming and also the revenue that is due to the VASPs for the usage of their services. 4 Billing is the function whereby the records generated by the charging function are transformed into bills requiring payment.

the operator and the service providers in order to enable operator and VASPs to make use of CAB information, as well as to configure its functionality through an open standardized interface (e.g., OSA API). The rest of this paper is organized as follows. In section 2 we describe the generic architecture proposed for flexible service provision and in section 3 the system for Charging, Billing and Accounting is introduced. In section 4, we present briefly the VASPs categories and the suitability of the proposed architecture for each VASP category while in section 5, we examine the OSA requirements and which of them are fulfilled by the introduced system. Section 6 concludes the paper. II.

ARCHITECTURE

In a typical UMTS network, a mobile user can access a value added service (VAS) offered by the operator or by a VASP. For the communication between the involved entities (i.e., user and VASP), the user establishes a PDP context [2] with the network. In other words, the user sets up a tunnel through the UTRAN (UMTS Terrestrial Radio Access Network) the SGSN (Serving GPRS Support Node) and the GGSN (Gateway GPRS Support Node) [3] [4]. Throughout the communication of a mobile user with a VASP, the SGSN and GGSN components collect charging information and transfer it to the Charging Gateway Functionality (CGF). The CGF as defined in [5] provides a mechanism to transfer charging information (Call Detail Records - CDRs) from the SGSN and GGSN nodes to the Billing system. The third generation mobile networks’ elements (GSNs nodes) collect and process significant information such as the Access Point Name Network Identifier5 (APN NI), the QoS values (requested by the user and negotiated by the network), the corresponding data volume counts (up-link and down-link packets) etc. Although these attributes can be exploited to design new flexible billing schemes, they are insufficient in addressing the problem of service differentiation. Whenever a PDP context to a VASP is established, the user can transfer through it several different application flows towards different services of the same VASP. However, the SGSN and GGSN nodes cannot distinguish these flows, since they all are identfied with the same PDP identifier and APN NI. Moreover existing standards do not allow the GSNs nodes to have information for layers above the IP (e.g., usage of TCP or UDP, RTP or HTTP flows).

5

The APN NI indicates the external network for which the PDP context is established.

The need of such information drives the development and deployment of new architectures, which should be able to provide network flow reporting with the required details for the services usage (service type, application port, protocol etc.). We call these systems Metering Devices (MDs). In Figure 1, a generic architecure for flexible service provision is introduced. The MD, as shown in Figure 1, should be placed in the edge of the core network in order to monitor all incoming or outgoing traffic. The MD could actually be a Layer 4 SmartSwitch-Router [6] that processes traffic over the IP layer and could provide the required information to an appropriate charging component. An alternative solution could be the deployment of the IPmeter approach [7] where all traffic is monitored by a device that is not involved in routing tasks.

VASP Service Manager VASP

CGF UTRAN

SGSN

GGSN

MD

VASP VASP

CAB

MD: Metering Device CAB: Charging Accounting Billing VASP: Value Added Service Provider

Figure 1: Generic Architecture for flexible service provision In addition, the MD is a dynamicaly configurable metering device, meaning that it collects meter data and generates charging records, called Value Added Service Records (VASDRs), only for specific flows specified by meter configuration information (metering scope). For this purpose we also introduce a new component called Service Manager [8], which is aware of the existence of VASPs and VASs (in terms of IP address, Port number etc.). The Service Manager is responsible for configuring the MD based on VAS specific requirements. Furthermore, the Service Manager can provide on demand a detailed description of the VASs (e.g., media types, encoding etc) and even a user friendly description of the respective billing scheme for the users. Furthermore, the MD can be configured to meter different flow attributes for selected flows (metered flow attributes) and generate VASDRs in specific intervals for each one (meter granularity). The transmission of the VASDRs from the MD to the

CAB can be initiated either by the MD (push model) or by the CAB (pull model). The CAB component communicates also with the CGF, from which it receives CDRs related to the core and access network chargeable events, in order to re-use existing functionality and to minimize modifications in the other network components (i.e., SGSN, GGSN). III.

THE INTRODUCED SYSTEM FOR CHARGING, BILLING AND ACCOUNTING

The CAB system, which has been fully specified in an SDL model and contains the charging, billing and accounting processes, fulfils the requirements for flexible charging, fair billing and generation of one itemised bill for all services [9]. Figure 2 illustrates the SDL model at block level of the CAB system.

Figure 2: SDL model of the CAB component The charging process receives the resource usage records, i.e. CDRs and VASDRs, from the respective network components. After processing these records, the charging process triggers: The billing process, which selects and instantiates the appropriate pricing and tariffing models from the CAB internal database or alternatively it queries the corresponding entity aware for the current pricing policies for the specific service usage. To this end, dynamic reconfiguration is enabled based on policy information provided by the VASP for the specific VAS in use. This action can be performed either through the Service Manager, or through an open API, based on the architecture or business model adopted.

The accounting process, which activates the appropriate accounting model in order to apportion revenue between the contributing players. In order to produce an itemized bill for all consumed services, the charging process must correlate the various resource usage records and determine the IMSI key – the mobile subscriber’s unique identifier. Currently, correlation of the CDRs with the VASDRs takes places on the basis of the mobile terminal’s IP address, while other alternatives remain under investigation. IV.

CHARGING BILLING AND ACCOUNTING ADAPTIVE TO EACH VHE - VASP CATEGORY

The Virtual Home Environment (VHE) [10] is a concept for personal service environment portability across network boundaries and between terminals. In VHE concept classification of different types of relationships between a VASP and a home or visited network are investigated.. The following types of relationships are identified: 1. The VASP is a Home Environment VASP (HEVASP) to the home network. This implies that there is a privileged relationship between the VASP and the home network for specific services and users. This may be supported by OSA when the VASP is a 3rd party service provider The level of privilege is likely to be higher than for a P-VASP. 2. The VASP is a privileged VASP (P-VASP) to the home or visited network. This implies that there is a privileged relationship between the VASP and the home or visited network for specific services and users. The level of privilege is likely to be lower than for a HEVASP and may vary between different PVASPs for the same or similar services. 3. The VASP is a non privileged VASP (NPVASP) to the home or visited network. This implies that there is no privileged relationship between the VASP and the home or visited network for this service and this user. The user may or may not have subscribed to the service, and has a direct business relationship with the NP-VASP. Moreover, the VASP does not use OSA for the specific user and service. When the VASP is a Home Environment VASP (HE-VASP), the home network has the responsibility for the charging and billing process. Therefore, the home network’s components collect information not only for the usage of its resources but also for the service usage. The home network is also responsible for the accounting of the revenue that is due to the HE-VASP.

In case that the VASP is a privileged VASP (PVASP), the home network permits the service to use particular capabilities but the full control of services remains to the P-VASPs. Thus, the service provider undertakes the charging and billing of the users for the service usage. When the VASP is a non privileged VASP (NPVASP), there is no privileged relationship between home network and service provider. Therefore, the NP-VASP should calculate the charge for its service usage and get directly revenue from the user. The assumptions that have been made during the design of the CAB system streamline with the requirements for flexible Charging models. In the first case, the home network provides charging and billing as a service to 3rd parties (HE-VASP). The CAB collects charging records from the network’s components (i.e., CGF, MD) and calculates separately the transport and the service part [11]. The home network bills the users and credits the HE-VASPs according to the agreements between them.

service provider identifies how the user should be charged for the usage of the service, the revenue for the call is split between the network operator and the service provider, the operator is enabled to provide charging/billing as a service to 3rd parties (service providers), monitor account access, etc. Table 1 illustrates the crucial requirements for the OSA Charging API and how they are fulfilled from the introduced system. It is apparent that some extensions are necessary in the APIs to be supported by the CAB in order to cover all the requirement (i.e., allow service provider to add information to network based charging records and to query the current account balance).

CAB & OSA interworking OSA requires:

The service provision by a NP-VASP is possible over the proposed platform and the CAB calculates only the transport charge for the allocation and usage of its network resources. The service bill is issued by the service provider, since the home network is not authorized to do that. In addition, the MD will not be configured to monitor the traffic to and from a NP-VASP, since there is no agreement between network operator and NP-VASP. Thus it cannot provide charging information to the CAB for such services usage. In case of a P-VASP, the network operator has a business agreement with the P-VASP, so the MD could monitor the incoming and outgoing traffic related to these services and generate charging records. Although the charging and billing is not responsible for the service charge, these charging records might be used or alternatively discarded by the MD. The CAB calculates the transport charge, while the service provider should estimate the service charge. In order the P-VASP to be able to use flexible billing schemes for the service usage, metering devices such as L4+ systems should be used to monitor the outgoing traffic from the PVASP network. Another possibility is the utilization of the charging information provided by the network’s components. In such case, a new interface between CAB and P-VASPs should be defined. V.

CAB ADAPTIVE TO THE ARCHITECTURE CONCEPTS

OSA

The CAB system fulfils most of the requirements for the OSA Charging API [12], namely: the

CAB fulfils:

• The service provider to define how much the subscriber should be charged for the usage of the service

• Dynamic reconfiguration of tariffs by the VASP through the VASM

• The charges for the call should be split between the involved parties

• Separation of transport and service charges

• The revenue for the call is split between the network operator and the service provider

• The accounting process calculates the portion that is due the VASP

• Ability to the services to add information to network based charging records

• With small extensions the CAB could provide an interface to the VASPs in order to add charging information

Table 1: CAB and OSA interworking The integration of the CAB as a network service capability server of the OSA architecture is investigated. The interface between the CAB and OSA that handles the method calls defined in the OSA charging API is currently under implementation. The full integration of CAB to the OSA Framework as a SCF of the network will enable offering charging information to authorised applications. VI.

CONCLUSIONS

In order to enable flexible service provision in 3G systems, the introduction of an adaptive charging, accounting and billing system is required. The CAB system presented in our paper is able to support advanced business models and is adaptive to VAS specific requirements, various charging models and architectures. Moreover, open APIs for reconfiguration purposes are under consideration.

VII.

REFERENCES

[1] M.Koutsopoulou, C. Farmakis, E. Gazis, “Subscription Management and Charging for Value Added Services in UMTS Networks”, IEEE Semiannual Vehicular Technology Conference VTC2001, May 2001, Rhodes, Greece [2] 3G TS 23.060: "3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; General Packet Radio Service (GPRS); Service description; Stage 2 (3G TS 23.060 version 3.5.0)" [3] 3G TS 23.002: "3rd Generation Partnership Project; Technical Specification Group Services and Systems Aspects; Network architecture (3G TS 23.002 version 3.2.0)" [4] 3G TR 23.922: "3rd Generation Partnership Project; Technical Specification Group Services and Systems Aspects; Architecture for an All IP network (3G TR 23.922 version 1.0.0)" [5] 3G TS 22.115: "3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Service aspects; Charging and Billing (3G TS 22.115 version 3.2.0 Release ’99)" [6] Layer 4 Switching: An Overview, http://www.enterasys.com/technologies/smarts witch-router

[7] Ipmeter White Paper, 2000, http://www.ipmeter.com/doc/whitepaper/t1.ht m [8] N. Alonistioti, E. Gazis, M. Koutsopoulou, S. Panagiotakis, “An application platform for downloadable VASs provision to mobile users”, IST Mobile Communications Summit 2000, Galway, Ireland, October 2000, pp. 309-314 [9] M.Koutsopoulou, E. Gazis, A. Kaloxylos, " A Novel Billing Scheme for UMTS Networks", International Symposium on 3rd Generation Infrastructure and Services, Athens, Greece, July 2001 [10] 3G TS 23.127: "3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Virtual Home Environment (3G TS 23.127 version 5.0.0)" [11] V. Gazis, M. Koutsopoulou, C. Farmakis, A. Kaloxylos, "A Flexible Charging and Billing Approach for the Emerging UMTS Network Operator Role", ATS 2001, Seattle, Washington, USA, April 2001 [12] 3G TS 22.127: "3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Service aspects; Service Requirement for the Open Services Access (OSA); Stage 1 (3G TS 22.127 version 4.0.0)"