Driving computer interconnection networks closer to saturation minimizes cost/performance and power consumption, but requires efficient congestion control to prevent catastrophic performance degradation during traffic peaks or "hot spot" traffic patterns. The InfiniBand™ Architecture provides such congestion control, but lacks guidance for setting its parameters. At its adoption, it was unproven that there were any settings that would work at all, avoid instability or oscillations. This paper reports on a simulation-driven exploration of that parameter space which verifies that the architected scheme can, in fact, work properly despite inherent delays in its feedback mechanism.