A new multiple QoS control scheme with equivalent-window CAC in ATM networks

This paper proposes a multiple QoS control scheme that combines the head-of-line priority (HOLP) discipline with equivalent-window connection admission control (CAC). The proposed scheme can support the different cell loss ratios of both delay-sensitive traffic in high-priority buffers and delay-tolerant traffic in low-priority buffers. The CAC scheme extends a measurement-based CAC algorithm for a single buffer to the low-priority buffer with the HOLP discipline to provide the cell loss ratio objective. We introduce an equivalent window for monitoring low-priority cell streams. The equivalent window size equals the period within which the number of times the low-priority buffer is scanned to read cells is constant. Thus the equivalent window size varies with the high-priority queueing state. Numerical results indicate that the proposed QoS control scheme using the equivalent-window CAC can utilize network resources more effectively than the conventional control scheme which is Virtual Path (VP) separation for different cell loss requirement services. In addition, it is confirmed that the proposed scheme provides conservative admissible loads. Thus, this proposed scheme can achieve large statistical gains while providing both high-priority and low-priority cell loss ratio objectives. The proposed scheme will be very useful for cost-effective multimedia services that have different QoS requirements.