I. Introduction
The diverse service requirements of emerging Internet applications foster the need for flexible and scalable IP quality-of-service (QoS) schemes. Two IP QoS solutions proposed by the Internet Engineering Task Force (IETF) are integrated services (IntServ) and differentiated services (DiffServ). The IntServ model [2] provides QoS guarantees for individual flows through resource reservation and admission control mechanisms. The reservations are requested using the resource reservation protocol (RSVP). IntServ requires each IP router on the transmission path to reserve resources for each flow, maintain per-flow state information, and check each data packet in transit to ensure service requirements. The overhead of maintaining per-flow state information and checking each packet of the flow for resource management makes IntServ not scalable and not workable administratively [3].