Feedback Control of Multiloop Abr Traac in Presence of Cbr/vbr Traac Transmission

Existing works on ABR feedback control design basically neglected the eeect of multiple feedback loop delays and high-priority CBR/VBR traac transmission. With multiloop delays, the already existing low-frequency high-magnitude oscillations of ABR traac within each loop can become much worsened. With CBR/VBR priority traac, the original control stability conditions can be ruined. This paper proposes a new ABR feedback control scheme where the eeects of multiloop delays and high-priority traac transmission are built into the control model. A so-called General Prediction Control (GPC) method is then applied to the control model for oscillation elimination and control stability. Our control objective is to minimize the unused link capacity subject to no congestion, where the ABR traac is adapted to the low-frequency variation of high-priority traac ow for high eeciency. Simulation study shows a signiicant improvement on achievable throughput as well as on control stability.