Reload cost trees and network design

In this paper we consider the notion of “reload costs” in network design. Reload costs occur in telecommunication networks using diverse technologies. For example, one of the products offered by commercial satellite service providers and their partners is a virtual private network (VPN) that can offer voice, video and data connectivity between all of the geographically dispersed locations of large corporate, government and military organizations. Typically, these VPNs are made up of satellite links and fiber optic cables. The use of diverse technologies at different junctions of the VPN results in an extra cost component (i.e., in addition to typical routing costs) that is associated with the equipment required to seamlessly bind them together. These interface costs are referred to as reload costs and depend on the technologies being connected. Moreover, these costs can sometimes dominate other costs such as the regular routing costs.