This read-only Counter32 counts hardware errors recorded on the whole monitored link (both ports combined) during this 15-minute long-term sample, with 4294967294 meaning the count is unknown. An admin treats a rising HardwareErrors count as a signal to inspect physical layer issues, such as failing NICs or cabling, on the whole monitored link (both ports combined) rather than looking at software or protocol causes. For example, a steady increase in HardwareErrors across consecutive 15-minute long-term samples on the whole monitored link (both ports combined), even while traffic volume stays flat, points toward a degrading physical interface rather than congestion.