Applies to ONTAP 9 FAS / AFF Systems CRC errors reporting on a single port Answer Cyclic Redundancy Check (CRC) errors are generally a layer 1 issue caused by a faulty port on the device or bad or inc...Applies to ONTAP 9 FAS / AFF Systems CRC errors reporting on a single port Answer Cyclic Redundancy Check (CRC) errors are generally a layer 1 issue caused by a faulty port on the device or bad or incompatible Ethernet cable or SFP. If network interface is stable and just rarely indicating CRC errors from ifstat -a output, in most cases those CRC errors are nothing to do with protocol layer performance issue. Additional Information additionalInformation_text