In the highest expert level, IP Plus, the maximum speeds can be achieved. We are now talking about the nominal or stress level test. At nominal speed, the test is performed at the speed of the pin function. At even higher speeds and/or extended parameters, we speak of the stress-level test. In this case, the specification is even exceeded. The tests in this level show whether your assembly is already working in the limit range or is close to the failure limit.
A typical test application is a Bit Error Rate Test at highspeed interfaces. IP Plus level programming is performed at highest speeds (> MBytes/s), because the programming data are transferred via the communication interface (e.g. Ethernet) as well.