We present a monotone waveform relaxation algorithm which produces very tig
ht upper and lower bounds of the transient response of a class of systems d
escribed by nonlinear differential-algebraic equations (DAEs) that satisfy
certain Lipschitz conditions. The choice of initial iteration is critical a
nd we give two methods of finding it. We show that the class of systems in
which monotone convergence of waveform relaxation is possible is actually l
arger than previously reported. Numerical experiments are given to confirm
the monotonicity of convergence of the algorithm.