IBM IBM IBM In this document we focus on RSVP-based resource reservations in a heterogeneous environment which includes ATM networks. We describe a method for establishing 'shortcuts' through an ATM network which avoids the performance penalty associated with level 3 processing in a 'classical RSVP over ATM' approach. For the case of guaranteed service we show how to map the RSVP flow characteristics to ATM call parameters, and thus enable end-to-end performance guarantees. We also discuss the extensions to RSVP and to ATM signaling required for the implementation of these solutions.