Why are undersized RX frames dropped when using the H-tile Hard IP for Ethernet Intel® FPGA IP or the E-tile Hard IP for Ethernet Intel® FPGA IP cores in MAC mode.

When using either the H-tile Hard IP for Ethernet Intel® FPGA IP or the E-tile Hard IP for Ethernet Intel® FPGA IP cores in MAC mode, undersized frames can be dropped by the RX MAC adapter without being reported in the RX MAC dropped frame counter.

If two frames are received back to back, and the frame starts are less than five ethernet blocks apart, the first of the two frames will be dropped, but not reported in the dropped frame counter.

Prior to version 18.1 of the Intel® Quartus® Prime Software, no workaround is available.

This problem has been fixed starting in version 18.1 of the Intel® Quartus® Prime Software by the addition of an RX MAC Adaptor dropped frame counter.