Consider a system where the interarrival times have an arbitrary distribution F, and there is a single server whose service distribution is G. Let Dn denote the amount of time the nth customer spends waiting in queue. Interpret Sn, Tn so that Dn+1 =

Dn + Sn − Tn, if Dn + Sn − Tn 0 0, if Dn + Sn − Tn < 0