8 Related Work

There are two major problems with current designs for VBR service a it is inherently hard to compactly and completely describe VBR tra c sources and b sustained peaks in the source rate substan tially degrade the performance We propose a new scheme Renegoti ated CBR RCBR that augments CBR service with fast renegotiation and bu er monitoring Analysis shows that the scheme is easily imple mentable and solves the problems above In more general terms we be lieve that a clean system design must rely on tra c management poli cies that clearly separate call level burst level and cell level time scales RCBR works well because it makes intelligent use of this time scale sep aration