  Explicit results are derived using simple and exact methods for the joint and
marginal queue-length distributions for the M/M/c queue with two non-preemptive
priority levels. Equal service rates are assumed. Two approaches are
considered. One is based on numerically robust quadratic recurrence relations.
The other is based on a complex contour-integral representation that yields
exact closed-form analytical expressions, not hitherto available in the
literature, that can also be evaluated numerically with very high accuracy.
