A Constraint Logic Programming based Decision Support System for Network Traffic Management G. Martini, C. Moiso, M. Porta CSELT Centro Studi E Laboratori Telecomunicazioni via Reiss Romoli 274, 10148 Torino (Italy) Ph.: +39-11-2286780; Fax: +39-11-2286909 Abstract One of the problems in network traffic management is to select the correct actions to improve the network performance in order to control network congestions caused by external factors, such as faults or overloads. The controls to apply are decided by the network operators that must hold a lot of data and requirements in consideration. This paper presents an experimental decision support system, whose purpose is to assist the network operators in the selection of the set of expansive controls called Temporary Alternative Routing (TAR) that is the best one w.r.t. a given optimum criterion. The system has been realized adopting an Advanced Information Processing technique that allows to integrate symbolic rules and linear program models: the Constraint Logic Programming (CLP) paradigm. The implementation language is a new CLP language, called VEL (i.e. Constraints And Logic in Italian), whose peculiarity is a set of optimization primitives well integrated with the CLP paradigm. At present, the system is under testing as a component of the network management module in a simulated environment. Keywords : Network Traffic Management, Constraint Logic Programming.