Cost Allocation in Communication Networks In hub networks there are a fixed number of interconnected facilities - the hubs. Each hub provides access to the network to a given number of non-hub clients, locations or users. Hub and spoke type arrangements by airlines are an example of such networks. They are also commonly found in communications. Hub networks are advantageous when there are economies of scale in provision of services as, when such economies exist, costs to each user of the network can be reduced through their participation and cooperation in the operation of the network. For this to occur, however, users must receive their `fair share` of the cost reductions resulting from the exploitation of economies of scale. In this proposal, the PI intends to develop computationally tractable means for determining fair cost allocations among users of hub or hub-like networks. Both game theoretic and heuristic approaches will be employed in the development of these allocation procedures.