ABR with bursty traffic sources

Available bit rate (ABR) service category defined by the ATM Forum Traffic Management Specification 4.0 uses feedback rate control. Such methods work well under many conditions but cannot react to very fast changes in load if the control delay is too long and changes in the load are large. A natural question is how well ABR-sources can use the spare capacity left over by the VBR/CBR-sources if control delays are long and the VBR-sources are bursty in two realistic patterns: either bursty and periodic sources or sources with a self-similar appearance. The performance of ABR has been studied extensively both with analysis and with simulations but the traffic sources, both for VBR and ABR, have usually been either too nice, often persistent, or the burstiness of the sources has been removed by arrival buffers. This paper presents some questions of the efficacy of ABR in the presence of these two kinds of bursty sources. Some simple improvements are proposed with the aim of solving the performance problems in these cases.