Abstract. In this paper we propose a new router architecture that combines both flexibility and performance. This router architecture aims at combining the best of two worlds: the commercial routers, which have a proven track for stability and performance but lack the flexibility of routers with open source operation system. The latter is particularly flexible because the source code is accessible for analysis and modification purposes as opposed to the traditional commercial routers, whose software can be altered by their manufacturers only. Motivation and State-of-the-ArtThe exponential growth of Internet traffic has yielded a dramatic development effort of the IP routers technology. Moreover, the deployment of value-added IP service offerings (ranging from a QoS-based access to the Internet to real-time services, like IP videoconferencing) has lead to an important development of specific capabilities (traffic conditioning, marking, scheduling and metering) that are supported by someif not all -the routers of the Internet. The consequence of the activation of such enhanced capabilities is twofold: a demand for an increase of the routers' switching performances together with the availability of multi-functional and multi-service routers.Other important concerns deal with IP security, multicast, and Virtual Private Networks services. Therefore, the IP routers that are exploited in a multi-service environment need to be flexible enough in order to address current and future requirements.For the past decade, Linux has received considerable interest not only from the research community, but also from the industry. An extensive description of Linux features and related bibliography can be found in [1]. Recently, an implementation for DiffServ over MPLS [2] has been released by some of the authors of this paper.