Principle (Buffering): The throughput of a closed line is non-decreasing in the size of any buffer.
The principle states that increasing the size of any buffer in the line
cannot cause throughput to decrease. The reason is that throughput is
proportional to the fraction of time the bottleneck station is busy. Whenever
a buffer gets full and blocks a station from working, it creates the possibility
of either blocking or starving the bottleneck. Increasing the size
of the buffer, therefore, decreases the likelihood of blocking and/or starving
and hence increases the fraction of time the bottleneck will be busy.