In the typical Resource Reservation Protocol (RSVP)/Intserv model@ applications request a specific Intserv service type and quantify the resources required for that service. For certain applications@ the determination of service parameters is best left to the discretion of the network administrator. For example@ ERP applications are often mission critical and require some form of prioritized service@ but cannot readily specify their resource requirements. To serve such applications@ we introduce the notion of the 'Null Service'. The Null Service allows applications to identify themselves to network Quality of Service (QoS) policy agents@ using RSVP signaling. However@ it does not require them to specify resource requirements. QoS policy agents in the network respond by applying QoS policies appropriate for the application (as determined by the network administrator). This mode of RSVP usage is particularly applicable to networks that combine differentiated service (diffserv) QoS mechanisms with RSVP signaling [intdiff]. In this environment@ QoS policy agents may direct the signaled application's traffic to a particular diffserv class of service.