In this paper we investigate issues related to the integration of QoS capabilities in the framework of IP switching technology. First, we propose an architecture which includes the RSVP protocol with minimal impact on the original structure and protocols of IP switching. This leads us to further investigate the queueing and scheduling mechanisms adopted both at the routing and the switching level in order to guarantee effective support of Guaranteed (GS) and Best-Effort (BE) services. Based on the observation that GS service typically results in network underutilization, we then introduce a new service class (BR) that provides flows with long-term rate guarantees without impacting GS flows and while exploiting their unused bandwidth. Second, we propose a possible implementation of this new service and we analyze it with the help of simulation. Finally we briefly discuss scalability problems in an integrated services model.