This Counter32 is a free-running, cumulative tally of PCIe Access Control Services (ACS) violations recorded against this PCIe endpoint's access-control enforcement since the counter was last reset by a reboot or reseat; concretely, a peer-to-peer transaction between PCIe functions was blocked because it violated the configured ACS isolation/redirection rules. Because it never wraps back to zero on its own, an admin uses it as the lifetime baseline against which the 15-minute/hourly/daily/weekly gauges on this same row are compared to spot fresh activity. A blade that shipped with this counter at 0 and now reads 187 has accumulated 187 such faults since it was last powered up, which on a healthy riser should stay at 0.