"For packet-oriented interfaces, the number of inbound\npackets that contained errors preventing them from being\ndeliverable to a higher-layer protocol. For character-\noriented or fixed-length interfaces, the number of\ninbound transmission units that contained errors\npreventing them from being deliverable to a higher-layer\nprotocol.\n\nDiscontinuities in the value of this counter can occur\nat re-initialization of the management system, and at\nother times as indicated by the value of\n'last-clear'." . . . . "Reference : RFC 2863: The Interfaces Group MIB - ifInErrors" .