VP Network Designer, a software tool that automates the tasks involved in the transaction of service orders in VP leased line services, is introduced here in this paper. The tool is composed of two functions: VP Design Explorer which, given a request for VP establishment, determines a disjoint backup and target VP routes to support fault tolerance under VP-APS scheme; Network Resource Administrator which provides data administering functions, useful in maintaining a clear insight into the state of the network. The paper focuses on the implementation of VP Design Explorer. A scheme, proposed as disjoint VP routes search, is used to evaluate a pair of VP routes that guarantee duct level independence. The scheme is based on an integer programming modeling approach, and is proved to be effective for evaluating disjoint paths in a hierarchical network. VP Design Explorer is equipped with an additional feature where, under conditions of resource shortage, it presents a set of additional resources that are necessary to satisfy VP demand, together with the VP routes that become possible by the additions. Formulation of the problem is attained through an extension of the disjoint VP routes search scheme. A prototype of VP Network Designer is presented and its performance tested using computer simulations. The tool is found to achieve a computational time performance in the order of seconds and minutes, for evaluating disjoint VP routes search problems under real life ATM network conditions.