The frame size is an important decision and the optimum value depends on the error rate of the link as well as the distribution of errors. Small frames have high protocol overhead but have the advantage that when an error occurs only a small number of bits are lost.
Large frames have lower protocol overhead but when one is lost a large number of bits are lost.
It is really the Gaussian error that determines the size of the frame that should be used. The burst errors affect the large and small frames almost the same, because a number of continuous frames will be in error. There is a need to compromise the throughput by picking a fixed frame size. The frame size was chosen to be 12 cells long, which is a good compromise for the types of errors that are investigated here. If there is only one link then there could be a optimum-sized frame, or even an adaptive frame size as is already implemented on other applications.