Effective inventory management is essential for improving the operational efficiency of distribution networks comprising a central distribution center (DC) and multiple retailers. This study investigates inventory replenishment strategies under three distinct decision-making structures within a distribution network: (1) decentralized without information sharing, (2) decentralized with information sharing, and (3) centralized control. A simulation model is developed to imitate the dynamic behavior of the network, capturing the operational interdependencies among members. The model tracks inventory levels and calculates total inventory management cost, including shortage, holding, over-storage, and ordering costs. Simulation results reveal how decision structures and information visibility influence replenishment logic and overall cost performance. The findings provide valuable insights into the trade-offs between autonomy, coordination, and cost efficiency in supply chain decision-making.