Performance Analysis of Concurrent PCOs in TTCN-3

This paper deals with a study and a mathematical model of concurrent Points of Control and Observation (PCOs) realized in Testing and Test Control Notation version 3 (TTCN-3). We study test scenarios that are gaining importance as TTCN-3 is emerging as a notation suitable for conducting load tests too. We investigate communication between parallel test components (PTCs) and analyze race conditions between the queues underlying the implemented PCOs. This way, we build an analytic model to investigate behavior of PCOs under stress conditions and to assess possible latencies messages in a TTCN-3 based load test system might suffer. We present a discrete-time Quasi Birth-Death process to predict performance indices of test components and we propose to use the results to avoid indefinite postponement in the communication of PTCs. Also, we aim to use the model for calculating traffic intensity limits under which it is feasible to use TTCN-3 for load testing. Furthermore, we present the output of the model together with an example load test scenario that is vulnerable to that types of