In this paper we introduce and investigate a new" path optimization problem which we denote as the All Hops Optimal Path AHOP problem. The problem involves identifying, for all hop counts, the optimal, i.e., minimumweight, path between a given source and destination. Our interest in such a problem originated in the context of Quality-of-Service QoS routing in networks. A goal of QoS routing is to improve a network's ability to satisfy user requirements by selecting paths for individual requests, which are based on both the network state and the request requirements, e.g., minimum bandwidth or maximum end-to-end delay constraints. In addition, in order to ensure e cient network operation, it is desirable that the paths also use the minimum possible amount of network resources, e.g., minimize the number of links hops used. As a results of these additional constraints, the path selection computation increases in complexity, and it becomes important to amortize this increase ove...