Improvements to the InfiniBand Congestion Control Mechanism

The InfiniBand Congestion Control mechanism (IB CC) is able to reduce the negative consequences of congestion in many situations. However, its effectiveness depends on a set of parameters that must be set by administrators. If the parameters are not appropriately configured, IB CC could negatively impact network performance. Additionally, no one has been able to find a universal parameter setting that can fit all situations. These difficulties prevent IB CC from being widely used. In this paper we propose several enhancements to the existing IB CC. First, our improved IB CC significantly reduces parameter configuration. Second, the congestion will be removed quickly. Third, a new utilization-driven approach and a new Link Bandwidth Availability Report (LBAR) approach are implemented to guide sending interfaces on how and when to adjust their injection rates. These adjustments are aware of the actual network condition, rather than relying on preconfigured parameters, as in the existing IB CC. Simulation results have demonstrated that our improved IB CC is able to reduce the congestion consequences efficiently and can adapt to various network topologies and traffic patterns.