Abstract - One of the more challenging and yet unresolved issues
which is paramount to the success of ATM networks is that of congestion
control for Available Bit Rate (ABR) traffic. Unlike other ATM service
categories, ABR provides a feedback mechanism, allowing interior nodes
to dictate source rates. Previous work has demonstrated how linear adaptive
control theory can be utilized to create a stable and efficient control
system for the purposes of ATM ABR congestion control. This paper investigates
our recently proposed adaptive controller that uses a finite impulse response
(FIR) filter to approximately invert the FIR plant. Specifically,
convergence issues are addressed in depth. In doing so, a proof is
provided for the convergence of the Normalized Least Mean Square (NLMS)
adaptive algorithm employing a DC tap (drift tap), allowing the proof to
extend beyond the (often-assumed) zero-mean case. Using a set of
reasonable assumptions, parameter convergence in the mean and mean square
is proven. Other issues pertaining to the stability of this controller
are presented.
Download On the Convergence of a Direct Adaptive Controller for ATM ABR Congestion Control (pdf, 230 KB)