Why does the 10-Gbps Ethernet MAC IP core not assert avalon_st_rx_error[4] when the actual payload length does not match the value of the length or type field?

If type/length field is smaller than the actual payload size, avalon_st_rx_error[4] which indicates a Invalid Payload Length is not asserted. 10-Gbps Ethernet MAC IP core only asserts avalon_st_rx_error[4] when all of the following conditions are met:

• Length/Type field is between 46 and 1500 for standard frames, 42 and 1500 for VLAN frame or 38 to 1500 for VLAN stacked frame
• The actual payload length is greater than the length/type field

This is due to accept frames with excessive padding. The IEEE std 802.3-2002 is ambiguous on how a device should handle frames with excessive padding. The UNH IOL recommends that a device accepts these frames.