A Framework for Policy-based Admission Control

The IETF working groups such as Integrated Services (called "intserv") and RSVP [1] have developed extensions to the IP architecture and the best-effort service model so that applications or end users can request specific quality (or levels) of service from an internetwork in addition to the current IP best-effort service. Recent efforts in the Differentiated Services Working Group are also directed at the definition of mechanisms that support aggregate QoS services. The int-serv model for these new services requires explicit signaling of the QoS (Quality of Service) requirements from the end points and provision of admission and traffic control at Integrated Services routers. The proposed standards for RSVP [RFC 2205] and Integrated Services [RFC 2211, RFC 2212] are examples of a new reservation setup protocol and new service definitions respectively. Under the int-serv model, certain data flows receive preferential treatment over other flows; the admission control component only takes into account the requester’s resource reservation request and available capacity to determine whether or not to accept a QoS request. However, the int-serv mechanisms do not include an important aspect of admission control: network managers and service providers must be able to monitor, control, and enforce use of network resources and services based on policies derived from criteria such as the identity of users and applications, traffic/bandwidth requirements, security considerations, and time-