A linear dynamic model for design of stable explicit-rate ABR control schemes

This paper focuses on the important stability issue of ABR traffic control with explicit-rate schemes. We develop a novel design approach with three advantages. First, the ABR rate is only adapted to the low-frequency variation of the underlying VBR traffic, which effectively prevents network congestion with much improved control stability. Second, a linear dynamic model is presented which makes the optimal control theory readily applied to the design of ABR control. Third, the control of different ABR loops is uncoupled, which significantly simplifies the control scheme. With this approach, stability analysis for the controlled network becomes feasible with the knowledge of VBR traffic characteristics. We propose a new explicit-rate ABR control scheme, called the H/sub 2/ scheme, which has the same level of design complexity as the existing schemes but with rigorously proved stability. The stability problem of the existing explicit rate schemes is also considered.