Verification of a GPRS Charging System in a Simulated Test Environment

1. Verification of a GPRS Charging System in a Simulated Test Environment Author: Kirsi Koskenheimo Supervisor: Prof. Raimo Kantola

2. Contents • Background and Goals • Flexible Charging in GGSN • Simulated Test Environment • Simulations and Results • Conclusions • Further Development

3. Background and Goals • Problem • GGSN (Gateway GPRS Support Node) support starting at Finland • Lack of knowledge about node, simulators and charging • How to solve it • Familiarize with GGSN, simulators and flexible charging • Setting up a test network • GGSN • Outline (charging node simulator) • Trembler (SGSN & MS/UE simulator) • Sgsnemu (SGSN emulator) • Dummynet (delay, queue and bandwidth limitation simulator) • Ethereal (network protocol analyzer) • Investigate the suitability of simulated test environment to testing of flexible charging • What is possible to test with simulators in test environment?

4. Flexible Charging in GGSN • Until now, PS charging often based on flat rate (monthly fee) • Flat rate pricing not enough especially on QoS network • Traditional charging volume and byte based • 3GPP specification of Flow Based Charging (FBC) • Possibility to separately charge services that use the same bearer • Identification of charging data • Based on QoS • Based on traffic destination • Charging rules • Separate rules based on Access Point Name (APN) • Separate rules for UL and DL • Separate rules for users

5. Free Area Portal home Search News Area News Promotions Customer Care Sports Business Internet Area International Rest of the Internet Ring tones Clips Games Downloads Area Different Browsing Areas

6. Ericsson solution: Service Aware Charging & Control (SACC) Enables charging based on different price levels Pre- and Postpaid Charging Byte- and Block-Based Charging Time- and Volume-Based Charging (kuva) Flexible Charging in GGSN

7. Simulated Test Environment

8. Simulations and Results • Determination of Test Cases • Cover a wide range of GGSN charging • Focus on prepaid users • Tested functionalities • Traffic filtering • Identification of Prepaid users • Charging at different time of day (ToD) • Service authorization (roaming, time) • Byte- and Block-Based charging • Time- and Volume-Based charging

9. Simulations and Results • Problems faced • Lack of components • (Not possible to generate all situations that exist in real life) • Not possible to filter traffic • Some exact messages • Not possible to perform with used simulators • Charging Data Records (CDR) • No stable system

10. Simulations and Results • Results • Simulated test environment is applicable to the testing of SACC charging • Basic SACC functions were tested successfully with simulators. • Traffic was filtered correctly • Prepaid users were identified correctly • Rating was dependent of ToD • Services could be authorized successfully • Services could be charged correctly based on time or volume • Services could be charged correctly based on byte or block • Basic functionalities can be more easily performed with simulators than with real charging nodes • More complex testing can also be executed but it requires more knowledge of charging and coding.

11. Conclusions • A diverse test environment was set up, although all testing possibilities were not used. • Knowledge of the SACC solution, the simulators and GGSN configuration was obtained • The features that can be tested in the simulated test environment were found and tested. • The created test environment enables more versatile testing than what was performed in this thesis.

12. Further Development • More specific testing • Specific message creation • In hexadecimal format • Different rates for specific days (e.g. weekends) • In hexadecimal format • Use of other PCs and simulators • Sgsnemu • Traffic generation • Dummynet • Propagation delays

13. Thank You • Comments? • Questions?

15. Additional Slides

16. PRS/CRF CCS/CCF EUS SURP GGSN/TPF SRAP/Gx SCAP/Gy CCF = Credit Control Function CCS = Credit Control Server CRF = Charging Rules Function EUS = External Update Server GGSN = Gateway GPRS Support Node PRS = Policy and Rating Server SCAP = Service Charging Application Protocol SRAP = Service Rating Application Protocol SURP = Subscription Update Request Protocol TPF = Traffic Plane Function 3GPP Specification vs. Ericsson Solution

17. Time-Based Block Charging Inactivity time period: 3 blocks (B) User is charged in: B1, B2, B3, B4, B9 User will not be charged for: B5, B6, B7, B8 (time between the 2nd and the 3rd charging event is larger than 3B)

18. Volume-Based Block Charging