The Erlang blocking formulas are the easiest (and probably best)
way to measure communications line usage, and to estimate how many
lines are needed to satisfy the demand.  It is equally well suited
to many other applications where some number of people are requesting
a limited resource, but unfortunately it's little known outside of
the telecommunications industry.  I presented a paper at two symposia
on it, and submitted a program which solved the various formulas to
previous RSX SIG tapes.  I'm putting it on the VAX SIG tape as it's
recently been used by some other people.  There is also the beginning
of a revised version of the paper that explains what you use this
stuff for. The original (more complete) paper is in [DTRSIG.ACCOUNTING].

B. Z. Lederman
ITT World Communications
67 Broad St. 28th Floor
New York, NY 10004-2464