This paper discusses three topics: (1) monotonicity properties of the transition probabilities for the initially empty \(\text{M}_t/ \text{G}/ \infty\) queue, and qualitative similarities with the M/M/1 queue; (2) a comparison of such probabilities for \(\text{M/M/}m/m\) and \(\text{M/M/}\infty\) queues; and (3) decomposition formulae for operating characteristics of the \(\text{M/M/}m/m+d\) queue. There is only brief mention of retrial systems.