  The busy period length distribution function knowledge is important for any
queue system, and for the MGINF queue. But the mathematical expressions are in
general very complicated, with a few exceptions, involving usually infinite
sums and multiple convolutions. So, in this work are deduced some bounds for
the MMINF system busy period length distribution function, meaning the second M
exponential service time, which analytic expressions are simpler than the exact
one. As a consequence, also some bounds for the MMINF system busy cycle length
distribution function are presented.
