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Verification of a GPRS Charging System in a Simulated Test Environment. Author: Kirsi Koskenheimo Supervisor: Prof. Raimo Kantola. Contents. Background and Goals Flexible Charging in GGSN Simulated Test Environment Simulations and Results Conclusions Further Development.
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Verification of a GPRS Charging System in a Simulated Test Environment Author: Kirsi Koskenheimo Supervisor: Prof. Raimo Kantola
Contents • Background and Goals • Flexible Charging in GGSN • Simulated Test Environment • Simulations and Results • Conclusions • Further Development
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?
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
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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
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
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
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.
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.
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
Thank You • Comments? • Questions?
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
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)