Performance of dynamic resources allocation with QoS guarantees for MPEG VBR video traffic transmission over ATM networks

摘要

Most of the new and interesting services that can be implemented over the B-ISDN networks include the transmission of variable bit rate (VBR) video traffic. Generally, the nature of this kind of services implies the need of a high quality of service (QoS). Unfortunately, to provide this high QoS to the VBR video traffic with a high efficiency in bandwidth utilization is not a trivial problem. This is due to the bursty nature of the VBR video traffic on different time scales. This traffic behavior is named self-similarity. In order to improve channel utilization, some services with bandwidth renegotiation have been proposed. In this work, a new mechanism to accomplish bandwidth renegotiation over ATM networks for VBR video traffic is presented. The mechanism is based on a previous characterization of the MPEG VBR video traffic at the group of pictures (GoP) level by means of a bidimensional Markov modulated fluid process (MMFP). A new element, with supervision and control functions, is proposed and validated. Moreover, the achieved benefits in terms of the bandwidth gain that can be expected with the renegotiation system are analytically computed using the fluid flow approximation. Finally, the applicability of the supervisor and controller elements and its parameters are studied using four long MPEG VBR sequences.