This paper describes the use of SDL for defining User Models for a test and measurement system whose purpose is to perform load tests of the control unit of an ISDN-PBX with realistic signalling traffic. The generation of realistic signalling traffic is based on the emulation of real users by User Models. The functional behaviour of a User Model is defined by an SDL process using a subset of the SDL syntax. The use of this type of User Models allows, besides the creation of messages according to distribution functions, to process messages received from the system under test and therefore to react appropriately on them, like a real user would do it. Normally several User Models are used together for a load test, so that the generated traffic is a realistic mixture of a variety of different user categories. The User Models are transformed to data structures for execution by the load test system. These data structures are optimized for efficiency in order to reach the target call rate of at least 30000 calls per hour on a standard workstation. The temporal behaviour of the User Models is defined separately by means of Event Generators which send signals to the User Models according to statistical distribution functions.


Environment simulation ISDN-PBX performance testing SDL traffic generator 


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Copyright information

© IFIP International Federation for Information Processing 2000

Authors and Affiliations

  • Thomas Steinert
    • 1
  • Georg Rößler
    • 2
  1. 1.Institute of Communication Networks and Computer EngineeringUniv. of StuttgartStuttgartGermany
  2. 2.Tenovis GmbH & Co. KGFrankfurt am MainGermany

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