We address several aspects related to managing re-entrant lines in a unifie
d manner - capacity allocation, inventory management and production control
. Our approach to study these systems is through simulation based optimizat
ion. Simulation offers the flexibility to model the complexities adequately
while the gradient computation (via Infinitesimal Perturbation Analysis (I
PA)) helps identify good solutions quickly. Our framework is a discrete tim
e capacitated multiple product production-inventory system operating under
a base stock policy. We analyze several different production and capacity a
llocation rules. We develop expressions for and validate the appropriate de
rivatives. These derivatives can then be used in an optimization tool which
enables the determination of optimal parameters for the several policies p
roposed. We also present a summary of insights obtained through an extensiv
e computational study.