The network design to support a digital data service (DDS) is a major design issue for telecommunications organizations. Typically, the DDS network consists of three components - hubs, end-offices, and customer locations. The hubs are the primary nodes that form the backbone infrastructure. The customers are connected by leased lines to the local end-office and the end- offices are in turn connected to the hubs. Typically, the customers are always connected to one end-office and each end-office is connected to one hub or node, thereby creating a star topology in the local access network. There are costs involved in setting up and operating the hub, the links connecting the hubs, links from the end-office to hub, and links from the customer to the end- office. The network designer is primarily interested in designing a network infrastructure that meets the customers’requirements at minimum cost.