Sensitivity of Blocking Probability in the Generalized Engset Model for OBS

The generalized Engset model can be applied to evaluate the blocking probability at an optical cross connect (OXC) of bufferless optical burst switching (OBS) system. For tractability, previous studies assumed that burst transmission time (on-time) and time intervals between bursts provided by the same input channel (off-time) are exponentially distributed. Here we aim to study the sensitivity of blocking probability to the shape of these distributions. Extensive numerical results demonstrate that the blocking probability is not very sensitive to on- and off-time distributions in general. We observe that higher variance of on- and off-time distributions may lead to better performance.