The sustainable cell rate concept for usage parameter control and connection admission control functions at an ATM UNI

In the process of bringing ATM traffic control into reality, the ATM Forum has proposed to adopt the sustainable cell rate (SCR) and its cell delay variation tolerance (CDVT_SCR) as traffic descriptors, besides the peak cell rate (PCR) and its cell delay variation tolerance (CDVT_PCR). The introduction of the SCR and the CDVT_SCR aims at obtaining a more efficient multiplexing of source traffic streams than PCR can provide. In this paper we provide guidelines for the choice of the SCR and CDVT_SCR values. We evaluate the impact of specific SCR and CDVT_SCR values on the usage parameter control (UPC) performance in case of measured MPEG and LAN traffic. A main result is the definition of conservative CAC rules at the access multiplexer that are easily implementable and yield guaranteed performance. The potential for further efficiency improvements is also explored