This field records how much the counter for FCoE frames received with an error condition, such as a corrupted encapsulation header or an invalid embedded FC frame changed during the specific collection interval this historical record captured — a frozen snapshot of that one interval's increase, not a live running total. For a network admin, a jump here on a specific vHBA's FCoE interface is one of the first places to check when a host reports intermittent SAN path failures. For example, 9 frames in the last interval on this specific FCoE path would already be worth a closer look, since this counter should normally sit at or near zero.