function L = L_MM1_queue(lambda,mu,N)
% L_MM1_QUEUE - The average number of customers in steady-state in a M/M/1 queue with capacity N
%   
% Written by:
% -- 
% John L. Weatherwax                2007-09-10
% 
% email: wax@alum.mit.edu
% 
% Please send comments and especially bug reports to the
% above email address.
% 
%-----

rho = lambda/mu; 
L   = (rho/(1-rho))*( N*rho^(N+1) - (N+1)*rho^N + 1 )/( 1 - rho^(N+1) );