TABLE OF CONTENTS Tests fall into two main types.
Deterministic (calls are generated with constant inter-arrival times)
This type of test is designed in such a way that the behaviour of the system is very precisely determined. It enables testing of whether:
the overload control logic is working correctly,
parameter values are being correctly assigned,
measurements (for statistics) are being correctly calculated.
Realistic load and configuration
These types of test are designed to determine the behaviour of the overload control when the test set-up is configured to mimic a more realistic network configuration, including the random nature of real traffic. Optimal or nearoptimal parameter values would be used. It enables a determination of whether the observed behaviour sufficiently closely matches that determined by modelling (discrete event simulation), and hence whether the code implements the end-to-end overload control design faithfully.
In each of the above two cases, it is the end-to-end behaviour of the control that is being tested, and therefore such tests should cover both the overload detection and the restriction schemes.
The generic overload control requirements described in section 7.5 imply the following non-obvious testing and modelling facilities:
call generators able to mimic the call state machine at source nodes, including the relevant parts of the overload control (if real switches are not available);
equipment able to measure response times and calling rates (before and after restriction at source nodes, and admitted and rejected at the target node) on a second-by-second basis required to observe the fast...
