This read-only PerfCounter64 captures a rate-limited Instantaneous Bit Rate sample for this flow point, i.e. the throughput reading taken after the configured policer had acted on the traffic. It gives an administrator the post-shaping counterpart to cmFlowPointHistoryIBR, useful for a quick side-by-side check of how much a flow point's rate is being trimmed by policy. For example, pulling both IBR and IBRRl for the same bin on a video-service flow point lets an engineer estimate how much bandwidth the policer is shaving off during that sample.